RARE DISEASE
Waardenburg syndrome type 1
Waardenburg syndrome type 1
Waardenburg syndrome type 1
Synonyms: WS1, Waardenburg syndrome type I
Synonyms: WS1, Waardenburg syndrome type I
Synonyms: WS1, Waardenburg syndrome type I
Drug discovery
70
papers
On emerging therapies
Overview
Waardenburg Syndrome Type 1 Clinical Overview
Waardenburg syndrome type 1 (WS1) is an autosomal dominant disorder caused by PAX3 gene mutations, characterized by congenital sensorineural hearing loss (69% of cases), dystopia canthorum (widened intercanthal distance), and pigmentary anomalies (heterochromia iridis, white forelock, premature graying). Diagnosis requires two major criteria (e.g., hearing loss, dystopia) or one major plus two minor criteria (synophrys, hypoplastic alae nasi). Rare complications include spina bifida. Penetrance is ~85% [1][2][10][14].
Therapies
Categories: rare developmental anomalies during embryogenesis, rare genetic diseases, rare ophthalmic disorders, rare otorhinolaryngological diseases, rare skin diseases
Research Papers
70 drug discovery papers about Waardenburg syndrome type 1. Recent publications:
70 drug discovery papers about Waardenburg syndrome type 1. Recent publications:
categories:
Small molecules
cell therapies
2024-07-26 | Auditory and speech outcomes of cochlear implantation in patients with Waardenburg syndrome: a meta-analysis.
This study aims to assess the potential efficacy of cochlear implantation as a treatment for patients with Waardenburg syndrome (WS) and to guide clinical work by comparing the effect of auditory and speech recovery after cochlear implantation in patients with WS and non-WS. PubMed, the Cochrane Library, CNKI, and Wanfang Data were sources for retrieving literature on cochlear implantation in WS, and clinical data meeting the inclusion criteria were meta-analyzed using RevMan5.41. A total of nine articles were included in this study, including 132 patients with WS and 815 patients in the control group. Meta-analysis showed that there are no significant differences in the scores for categories of audit performance (CAP), speech intelligibility rating (SIR), and parents' evaluation of aural/oral performance of children (PEACH) between the WS group and the control group. Cochlear implantation demonstrates comparable auditory and speech recovery outcomes for WS patients and non-WS patients.
2023-11-20 | Cochlear implantation in Waardenburg syndrome: Systematic review and meta-analysis.
Waardenburg syndrome (WS) is a genetic condition associated with moderate to profound sensorineural hearing loss. The aim of this review is to characterize cochlear implant (CI) outcomes in patients with a confirmed clinical diagnosis of WS. MEDLINE, Ovid EMBASE, and Cochrane Library. All reports describing defined sets of patients with WS who underwent CI and subsequent evaluation of clinical outcomes were included. To harmonize outcome data between studies that used different measures, a binary variable Favored CI was developed to capture success of procedures (1 = favored, 0 = unfavored) based on original authors' description, commentary, discussion, and conclusions. Expert reviewers independently reviewed and selected articles, extracted data and scored Favored CI values. Synthetic and analytic meta-analyses were implemented using standard analytic techniques. Twenty articles meeting inclusion criteria provided data on 192 WS patients and 210 CIs. The mean age at CI was 3.8 years (95% confidence interval [95%CI]; 3.1-4.5 years), and the mean duration of follow up was 5.2 years (95% CI; 3.4-7.0 years). Surgical complications were rare (11/210 implants, 5.2%) where gusher was the most common complication. CIs yielded favorable hearing outcomes in 90% (95% CI; 84-94%) of cases, and appear successful for those with temporal bone anomalies (p = 0.04). Quantitative synthesis of the study data demonstrates that in the majority of patients with WS, CI yield favorable hearing outcomes and low rates of surgical complications. CI has shown to provide clinical benefits in patients with WS.
2011-08-19 | Functional melanocytes derived from human pluripotent stem cells engraft into pluristratified epidermis
Melanocytes are essential for skin homeostasis and protection, and their defects in humans lead to a wide array of diseases that are potentially extremely severe. To date, the analysis of molecular mechanisms and the function of human melanocytes have been limited because of the difficulties in accessing large numbers of cells with the specific phenotypes. This issue can now be addressed via a differentiation protocol that allows melanocytes to be obtained from pluripotent stem cell lines, either induced or of embryonic origin, based on the use of moderate concentrations of a single cytokine, bone morphogenic protein 4. Human melanocytes derived from pluripotent stem cells exhibit all the characteristic features of their adult counterparts. This includes the enzymatic machinery required for the production and functional delivery of melanin to keratinocytes. Melanocytes also integrate appropriately into organotypic epidermis reconstructed in vitro. The availability of human cells committed to the melanocytic lineage in vitro will enable the investigation of those mechanisms that guide the developmental processes and will facilitate analysis of the molecular mechanisms responsible for genetic diseases. Access to an unlimited resource may also prove a vital tool for the treatment of hypopigmentation disorders when donors with matching haplotypes become available in clinically relevant banks of pluripotent stem cell lines.
2010-04-26 | Dysplasia of the cerebellum in Waardenburg syndrome: outcomes following cochlear implantation.
This study provides the first description of isolated cerebellar dysplasia associated with Waardenburg syndrome (WS) and includes a review of cochlear implant outcomes in 42 WS patients. A 1-year-old male infant presented with speech delay, iris heterochromia, profound hearing loss, and an asymmetric, underdeveloped right occipital skull on CT imaging. Brain MRI demonstrated a hypoplastic right cerebellum, no hydrocephalus, normal auditory nerves and brainstem. He underwent successful bilateral sequential cochlear implantation. Cochlear implants remain a reasonable habilitative option for WS patients with congenital deafness, including those with cerebellar abnormalities.
2007-02-13 | The developmental biology of melanocytes and its application to understanding human congenital disorders of pigmentation.
In the past 15 years, a fruitful interplay between the description of mutations associated with human congenital disorders of pigmentation, the discovery of the molecular basis of murine coat color mutants, and the elucidation of determinants of melanocyte development from the neural crest has led to rapid advancement in the understanding of these disorders and the developmental biology underlying them. The insight gained about these human disorders from similar mouse models has facilitated progress that might not otherwise have occurred so rapidly. Clearly more work remains to be done, especially on the discovery of additional genes in humans that underlie the majority of WS2 cases not attributable to mutations in MITF. Sensitized genetic screens, using random mutagenesis in combination with existing mutant coat color alleles, may help uncover additional genes regulating melanocyte development in mice. Such studies would provide examples whose human homologues could be tested for mutations in patients who have pigmentation disorders that are currently unclassifiable. Intervention in developmental disorders is a challenging prospect. Nonetheless, it is imaginable that additional studies of the determinants of melanocyte survival during and after development could lead to strategies designed to maintain or replace functionally defective melanocytes, especially in localized regions such as the inner ear. The growing interest among investigators in the melanocyte as a model cellular system, with striking phenotypes across species, ensures that the field of melanocyte development and the studies of congenital disorders of pigmentation will remain vibrant in the foreseeable future.
proteins
2026-02-13 | SOX10 Mutation of Waardenburg Syndrome With Hypogonadism: A Report of 2 Cases.
Waardenburg syndrome (WS) is a complex genetic disorder primarily characterized by auditory and pigmentary abnormalities, resulting from neural crest cell migration disorders. We reported 2 genetically confirmed SOX10-mutant WS cases illustrating critical management principles. Both patients underwent early auditory intervention (case 1: cochlear implantation at age 3; case 2: hearing aids from age 2), resulting in preserved age-appropriate language acquisition. Each case manifested delayed puberty with biochemical evidence of hypogonadotropic hypogonadism, necessitating gonadotropin therapy to potentiate virilization and preserve fertility. Multidisciplinary care and emerging therapeutic approaches offer hope for better management. Further studies are warranted to improve the diagnosis, treatment, and quality of life of patients with WS.
2011-06-15 | The MADS box transcription factor MEF2C regulates melanocyte development and is a direct transcriptional target and partner of SOX10
Waardenburg syndromes are characterized by pigmentation and autosensory hearing defects, and mutations in genes encoding transcription factors that control neural crest specification and differentiation are often associated with Waardenburg and related disorders. For example, mutations in SOX10 result in a severe form of Waardenburg syndrome, Type IV, also known as Waardenburg-Hirschsprung disease, characterized by pigmentation and other neural crest defects, including defective innervation of the gut. SOX10 controls neural crest development through interactions with other transcription factors. The MADS box transcription factor MEF2C is an important regulator of brain, skeleton, lymphocyte and cardiovascular development and is required in the neural crest for craniofacial development. Here, we establish a novel role for MEF2C in melanocyte development. Inactivation of Mef2c in the neural crest of mice results in reduced expression of melanocyte genes during development and a significant loss of pigmentation at birth due to defective differentiation and reduced abundance of melanocytes. We identify a transcriptional enhancer of Mef2c that directs expression to the neural crest and its derivatives, including melanocytes, in transgenic mouse embryos. This novel Mef2c neural crest enhancer contains three functional SOX binding sites and a single essential MEF2 site. We demonstrate that Mef2c is a direct transcriptional target of SOX10 and MEF2 via this evolutionarily conserved enhancer. Furthermore, we show that SOX10 and MEF2C physically interact and function cooperatively to activate the Mef2c gene in a feed-forward transcriptional circuit, suggesting that MEF2C might serve as a potentiator of the transcriptional pathways affected in Waardenburg syndromes.
2001-03-29 | Regulation of Pax3 transcriptional activity by SUMO-1-modified PML.
Pax3 is an evolutionarily conserved transcription factor that plays a major role in a variety of developmental processes. Mutations in Pax3 lead to severe malformations as seen in human Waardenburg syndrome and in the Splotch mutant mice. The transcriptional activity of Pax3 was recently shown to be repressed by Daxx whereas the oncogenic fusion protein Pax3-FKHR is unresponsive to this repressive action. Here we demonstrate that Daxx-mediated repression of Pax3 can be inhibited by the nuclear body (NB)-associated protein PML. Interestingly, this suppression of Daxx properties correlates with its recruitment to the NBs. Factors such as arsenicals and interferons that enhance NB formation, trigger both the targeting of Daxx to these nuclear structures and the relief of the repressive activity of Daxx. Conversely, lack of structurally intact NBs profoundly impairs Pax3 transcriptional activity, likely by increasing the pool of available nucleoplasmic Daxx. Moreover, a PML mutant that can not be modified by the ubiquitin-related SUMO-1 modifier is no more able to interact with Daxx. Consistently, such a mutant fails both to inhibit the Daxx repressing effect on Pax3 and to induce its accumulation into the NBs. Taken together, these results argue that SUMO-1 modified PML can derepress Pax3 transcriptional activity through sequestration of the Daxx repressor into the NBs and suggest a role for these nuclear structures in the transcriptional control by Pax proteins. Oncogene (2001) 20, 1 - 9.
gene therapies
2025-10-27 | Mild features of partial PAX3 deletion in patients with prenatal Waardenburg syndrome: a case report and literature review.
Waardenburg syndrome (WS) is a group of autosomal dominant hereditary disorders characterized by auditory-pigmentary abnormalities. Haploinsufficiency of paired box 3 (PAX3) gene is one of the known pathogenic mechanisms. However, clinical phenotypes are difficult to predict precisely in fetuses harboring PAX3 haploinsufficiency. In this study, we report a family with a PAX3 deletion encompassing exons 1-4, in which clinical manifestations ranged from normal to mild abnormalities. A 22-year-old woman (gravida 2, para 0) was referred to our prenatal center at 18 weeks of gestation due to a history of congenital spina bifida in her previous pregnancy. Chromosomal analysis had been performed on fetal tissue from the terminated pregnancy and on amniotic fluid obtained during the current pregnancy. A rare partial deletion of PAX3 gene was identified and confirmed to be of paternal origin. A diagnosis of WS was established based on the clinical features of the father. However, the newborn from the second pregnancy exhibited normal phenotypes after birth. This work suggests that deletions encompassing the promoter and functional domains of PAX3 gene functionally represent a haploinsufficiency mechanism, which leads to variable clinical manifestations. These findings broaden our understanding of copy number variation analysis and genetic counseling in prenatal settings. In addition, PAX3 gene should be considered a candidate gene in cases presenting with auditory-pigmentary abnormalities or neural tube defects of unknown etiology.
2025-08-01 | Full length transcriptomic profiling reveals insights into the white coat phenotype in Waardenburg syndrome mice harboring the Mitf R324del mutation.
Waardenburg syndrome (WS) is distinguished by depigmented patches of hair and skin, striking blue eyes and sensorineural hearing loss. Studies on alternative splicing (AS) in the abnormal pigmentation in skin in WS are currently poorly understood. In this study, we conducted comprehensive full-length transcriptome sequencing analysis on abdominal skin tissues from mice harboring the Mitf p.R324del mutation and wild-type controls. Our analysis revealed 3619 differentially expressed genes (DEGs), with 1916 upregulated and 1703 downregulated. Notably, pigment-associated genes and related signaling pathways were significantly enriched. Additionally, we identified extensive AS events in the skin tissue of Mitf mutant mice, including 97 A3, 85 A5, 101 AF, 42 AL, 8 MX, 44 RI, and 184 SE events (P < 0.05), suggesting AS events may contribute to the pigment distribution patterns in Mitf p.R324del mutation mice. Furthermore, we observed downregulation of Dct, Mlana, and Snai2, which indicates that Mitf mutations disrupt neural crest cells into melanocytes, melanosome structure, and melanin biosynthesis. Overall, our results support that variation in gene expression and AS are important and complementary mechanisms governing pigmentation defects in WS.
2025-05-15 | The Diverse Genetic Landscape of Hearing Impairment in South African Families.
To elucidate the genetic etiology of hearing impairment (HI) in South Africa, 45 nonsyndromic HI (NSHI) and syndromic HI (SHI) families with ≥ 2 affected members were analyzed. Exome and sanger sequencing were used to identify causal genes. For NSHI, 14 of 24 families segregated variants in NSHI genes, that is, CDH23, GJB2, MITF, MYO7A, MYO15A, PCDH15, POU3F4, REST, SLC26A4, TMPRSS3, and WFS1. For the 21 SHI families, 14 have Waardenburg syndrome, two Branchio-Oto-Renal syndromes, and one each with Bartter, Chudley-McCullough, Deafness-Albinism, MYH9-related disorder, and Pendred syndromes. The cause of SHI was determined for 14 families, with EDN3, EDNRB, GPSM2, MITF, MYH9, SLC12A1, and SLC26A4 underlying the syndrome in a single family, EYA1 in two families, and PAX3 in five families. For the NSHI and SHI genes, 52.9% and 35.7% of the variants, respectively, have not been reported in disease etiology. Additionally, two Waardenburg families segregated variants in NSHI genes, BDP1 and MYO6, but these findings need to be validated. This study enhances the understanding of the genetic landscape of HI in South Africa, revealing a high level of locus and allelic heterogeneity. Studying diverse populations provides new insights into HI etiology that, in turn, can improve genetic diagnosis and personalized management.
2025-04-18 | A novel noncanonical splicing pathogenic variant in PAX3 associated with Waardenburg Syndrome type 1 in an Iranian family
Abstract Background Waardenburg syndrome type 1 (WS1) is an uncommon autosomal dominant (AD) genetic disorder. The primary cause of WS1 has been shown to be the pathogenic variants of PAX3 , which encodes a protein that belongs to the paired box family (Paired Box 3). Variable manifestations of sensorineural hearing impairment, pigmentation abnormalities, and other clinical signs have been observed in individuals with WS1. Here, we report an Iranian pedigree affected by WS1, which was caused by a novel pathogenic splicing variant in PAX3 . Materials and methods WS1 was diagnosed in a 5-year-old girl according to the Waardenburg Syndrome Consortium criteria. According to a thorough family history, four relatives were affected. Exome sequencing (ES), combined with Sanger sequencing, was used in genetic studies. Results We identified a novel noncanonical splicing variant, NM_181458.4: c.86-3C > G, in PAX3 . In addition, the patient’s father was heterozygous for this variant. Conclusions This study highlights phenotypic variability in Iranian WS1 patients and demonstrates that ES has enabled us to better understand genetic diagnosis and expand the range of WS1 genetic variants.
2024-04-27 | Clinical and Genetic Correlation in Neurocristopathies: Bridging a Precision Medicine Gap.
Neurocristopathies (NCPs) encompass a spectrum of disorders arising from issues during the formation and migration of neural crest cells (NCCs). NCCs undergo epithelial-mesenchymal transition (EMT) and upon key developmental gene deregulation, fetuses and neonates are prone to exhibit diverse manifestations depending on the affected area. These conditions are generally rare and often have a genetic basis, with many following Mendelian inheritance patterns, thus making them perfect candidates for precision medicine. Examples include cranial NCPs, like Goldenhar syndrome and Axenfeld-Rieger syndrome; cardiac-vagal NCPs, such as DiGeorge syndrome; truncal NCPs, like congenital central hypoventilation syndrome and Waardenburg syndrome; and enteric NCPs, such as Hirschsprung disease. Additionally, NCCs' migratory and differentiating nature makes their derivatives prone to tumors, with various cancer types categorized based on their NCC origin. Representative examples include schwannomas and pheochromocytomas. This review summarizes current knowledge of diseases arising from defects in NCCs' specification and highlights the potential of precision medicine to remedy a clinical phenotype by targeting the genotype, particularly important given that those affected are primarily infants and young children.
small molecules
2025-06-25 | [Mechanisms of enhanced noise susceptibility in waardenburg syndrome Sox10 p.S100Rfs*9 mutant mice].
Objective:To investigate the impact of Waardenburg syndrome（WS） -associated Sox10 p.S100Rfs*9 mutation on inner ear function and its mechanism in noise-induced hearing impairment. Methods:A mice model carrying the Sox10 p.S100Rfs*9 mutation was established using CRISPR-Cas9 gene editing technology. Auditory phenotypes were assessed under baseline conditions and after noise exposure（96 dB SPL, 2 hours）. Auditory brainstem response（ABR） tests were performed to evaluate hearing function, combined with immunofluorescence staining of cochlear basilar membrane whole-mounts to observe hair cells and ribbon synapses. Transcriptome sequencing was conducted to analyze molecular mechanisms. Results:Sox10 p.S100Rfs*9 heterozygous mice exhibited normal hearing thresholds with characteristic ventral pigmentation abnormalities under baseline conditions. Following noise exposure, mutant mice showed significantly higher ABR thresholds at 24 000 Hz compared to wild-type controls（[60.00±6.12]vs[48.13±4.28]dB SPL, P<0.000 1）, and a significant reduction in ribbon synapses（CtBP2-positive puncta） in the basal turn（[55.0±2.3]vs[64.8±3.3]per inner hair cell, P=0.006 6）, while hair cell morphology and number remained intact. Transcriptome analysis revealed altered expression of genes involved in immune regulation, membrane structures, ion channels, and neuroactive ligand-receptor interactions. Conclusion:The Sox10 p.S100Rfs*9 mutation does not alter baseline hearing function but significantly increases inner ear susceptibility to noise damage, primarily manifested as enhanced ribbon synapse vulnerability, especially in high-frequency regions. This gene-environment interaction reveals that Sox10 haploinsufficiency may compromise noise tolerance by affecting synaptic stability and inner ear protective mechanisms. These findings provide new perspectives on the phenotypic heterogeneity in WS patients and theoretical basis for individualized noise protection strategies for patients carrying SOX10 mutations.
2022-02-11 | Acetylation reprograms MITF target selectivity
Abstract The ability of transcription factors to discriminate between different classes of binding sites associated with specific biological functions underpins effective gene regulation in development and homeostasis. How this is achieved is poorly understood. The microphthalmia-associated transcription factor MITF is a lineage-survival oncogene that plays a crucial role in melanocyte development and melanoma. MITF suppresses invasion, reprograms metabolism and promotes both proliferation and differentiation. How MITF distinguishes between differentiation and proliferation-associated targets is unknown. Here we show that compared to many transcription factors MITF exhibits a very long (>100s) residence time which is reduced by p300/CBP-mediated MITF acetylation at K206. While K206 acetylation also decreases genome-wide MITF DNA-binding affinity, it preferentially directs DNA binding away from differentiation-associated CATGTG motifs toward CACGTG elements. The results reveal an acetylation-mediated switch that suppresses differentiation and provides a mechanistic explanation of why a human K206Q MITF mutation is associated with Waardenburg syndrome.
2021-04-05 | Expression of unfolded protein response markers in the pheochromocytoma with Waardenburg syndrome: a case report.
It is clinically emergent to further understand the pathological mechanism to advance therapeutic strategy for endocrine tumors. A high amount of secretory protein with tumorigenic triggers are thought to induce unfolded protein response in endoplasmic reticulum in endocrine tumors, but its evidence is limited. A 40-year-old woman had an approximately 10-year history of intermittent headaches. After the incidental detection of a mass in her right adrenal gland by CT scan, she was admitted to our hospital. She had been diagnosed as type 1 Waardenburg syndrome with the symptoms of dystopia canthorum, blue iris, and left sensorineural hearing loss. Urinary catecholamine levels were markedly elevated. 123I-MIBG scintigraphy showed uptake in the mass in her adrenal gland. After the adrenalectomy, her headaches disappeared and urinary catecholamine levels decreased to normal range within 2 weeks. Genome sequencing revealed germline mutation of c.A175T (p.Ile59Phe) in transcription factor PAX3 gene and somatic novel mutation of c.1893_1898del (p. Asp631_Leu633delinsGlu) in proto-oncogene RET in her pheochromocytoma. RNA expression levels of RET were increased 139 times in her pheochromocytoma compared with her normal adrenal gland. Those of unfolded protein response markers, Bip/GRP78, CHOP, ATF4, and ATF6, were also increased in the pheochromocytoma. We report a rare case of pheochromocytoma with type 1 Waardenburg syndrome. This is the first case to show the activation of unfolded protein response in the pheochromocytoma with the novel somatic mutation in RET gene. Our findings may support that unfolded protein response is activated in endocrine tumors, which potentially could be a candidate of therapeutic target.
2014-08-14 | Targeting melanocyte and melanoma stem cells by 8-hydroxy-2-dipropylaminotetralin
Monobenzyl ether of hydroquinone (MBEH) is cytotoxic towards melanocytes. Its treatment efficacy is limited by an inability to eradicate stem cells. By contrast, 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-DPAT) affects melanocyte stem cell survival. MBEH and 8-DPAT were added to melanocytes and melanoma cells to compare cytotoxicity. Stem cell content among viable cells was determined by fluorocytometry using markers CD34, Pax3, and CD271. Immunostaining was used to identify stem cells in skin explants treated with MBEH or 8-DPAT ex vivo. Mice were exposed to MBEH or 8-DPAT and scanned for depigmentation before harvesting skin. MBEH exposure prompted a relative increase in stem cells among cultured melanocytes and melanoma cells, as treatment preferentially eliminated differentiated cells and spared the stem cells. Viability of this remaining, enriched stem cell population was however rapidly reduced by exposure to 8-DPAT within melanocyte and melanoma cell cultures. In human skin explants, the abundance of melanocyte stem cells was also visibly reduced after 8-DPAT treatment, in contrast to tissue exposed to MBEH. Meanwhile, significant depigmentation of the mouse pelage and loss of differentiated melanocytes was observed in vivo in response to topical application of MBEH, but not 8-DPAT. Prolonged application of the latter agent instead appeared to effectively reduce the abundance of melanocyte stem cells in the dermis. This furthers the idea that MBEH and 8-DPAT target complementary cell populations. Results indicate that combination treatment may demonstrate superior therapeutic activity by eliminating both differentiated and tumor initiating populations.
2014-05-29 | [Hereditary hypomelanocytoses: the role of PAX3, SOX10, MITF, SNAI2, KIT, EDN3 and EDNRB genes].
Hypo- and hyperpigmentation disorders are the most severe dermatological diseases observed in patients from all over the world. These disorders can be divided into melanoses connected with disorders of melanocyte function and melanocytoses connected with melanocyte development. The article presents some hereditary hypomelanocytoses, which are caused by abnormal melanoblast development, migration and proliferation as well as by abnormal melanocyte viability and proliferation. These disorders are represented by Waardenburg syndrome, piebaldism and Tietz syndrome, and are caused by different mutations of various or the same genes. The types of mutations comprise missense and nonsense mutations, frameshifts (in-frame insertions or deletions), truncating variations, splice alterations and non-stop mutations. It has been demonstrated that mutations of the same gene may cause different hypopigmentation syndromes that may have similar phenotypes. For example, mutations of the MITF gene cause Waardenburg syndrome type 2A as well as Tietz syndrome. It has also been demonstrated that mutations of different genes may cause an identical syndrome. For example, mutations of MITF, SNAI2 and SOX10 genes are observed in Waardenburg syndrome type II and mutations of EDNRB, EDN3 and SOX10 genes are responsible for Waardenburg syndrome type IV. In turn, mutation of the KIT gene and/or heterozygous deletion of the SNAI2 gene result in piebaldism disease. The knowledge of the exact mechanisms of pigmentary disorders may be useful in the development of new therapeutic approaches to their treatment.
cell therapies
2024-07-26 | Auditory and speech outcomes of cochlear implantation in patients with Waardenburg syndrome: a meta-analysis.
This study aims to assess the potential efficacy of cochlear implantation as a treatment for patients with Waardenburg syndrome (WS) and to guide clinical work by comparing the effect of auditory and speech recovery after cochlear implantation in patients with WS and non-WS. PubMed, the Cochrane Library, CNKI, and Wanfang Data were sources for retrieving literature on cochlear implantation in WS, and clinical data meeting the inclusion criteria were meta-analyzed using RevMan5.41. A total of nine articles were included in this study, including 132 patients with WS and 815 patients in the control group. Meta-analysis showed that there are no significant differences in the scores for categories of audit performance (CAP), speech intelligibility rating (SIR), and parents' evaluation of aural/oral performance of children (PEACH) between the WS group and the control group. Cochlear implantation demonstrates comparable auditory and speech recovery outcomes for WS patients and non-WS patients.
2023-11-20 | Cochlear implantation in Waardenburg syndrome: Systematic review and meta-analysis.
Waardenburg syndrome (WS) is a genetic condition associated with moderate to profound sensorineural hearing loss. The aim of this review is to characterize cochlear implant (CI) outcomes in patients with a confirmed clinical diagnosis of WS. MEDLINE, Ovid EMBASE, and Cochrane Library. All reports describing defined sets of patients with WS who underwent CI and subsequent evaluation of clinical outcomes were included. To harmonize outcome data between studies that used different measures, a binary variable Favored CI was developed to capture success of procedures (1 = favored, 0 = unfavored) based on original authors' description, commentary, discussion, and conclusions. Expert reviewers independently reviewed and selected articles, extracted data and scored Favored CI values. Synthetic and analytic meta-analyses were implemented using standard analytic techniques. Twenty articles meeting inclusion criteria provided data on 192 WS patients and 210 CIs. The mean age at CI was 3.8 years (95% confidence interval [95%CI]; 3.1-4.5 years), and the mean duration of follow up was 5.2 years (95% CI; 3.4-7.0 years). Surgical complications were rare (11/210 implants, 5.2%) where gusher was the most common complication. CIs yielded favorable hearing outcomes in 90% (95% CI; 84-94%) of cases, and appear successful for those with temporal bone anomalies (p = 0.04). Quantitative synthesis of the study data demonstrates that in the majority of patients with WS, CI yield favorable hearing outcomes and low rates of surgical complications. CI has shown to provide clinical benefits in patients with WS.
2011-08-19 | Functional melanocytes derived from human pluripotent stem cells engraft into pluristratified epidermis
Melanocytes are essential for skin homeostasis and protection, and their defects in humans lead to a wide array of diseases that are potentially extremely severe. To date, the analysis of molecular mechanisms and the function of human melanocytes have been limited because of the difficulties in accessing large numbers of cells with the specific phenotypes. This issue can now be addressed via a differentiation protocol that allows melanocytes to be obtained from pluripotent stem cell lines, either induced or of embryonic origin, based on the use of moderate concentrations of a single cytokine, bone morphogenic protein 4. Human melanocytes derived from pluripotent stem cells exhibit all the characteristic features of their adult counterparts. This includes the enzymatic machinery required for the production and functional delivery of melanin to keratinocytes. Melanocytes also integrate appropriately into organotypic epidermis reconstructed in vitro. The availability of human cells committed to the melanocytic lineage in vitro will enable the investigation of those mechanisms that guide the developmental processes and will facilitate analysis of the molecular mechanisms responsible for genetic diseases. Access to an unlimited resource may also prove a vital tool for the treatment of hypopigmentation disorders when donors with matching haplotypes become available in clinically relevant banks of pluripotent stem cell lines.
2010-04-26 | Dysplasia of the cerebellum in Waardenburg syndrome: outcomes following cochlear implantation.
This study provides the first description of isolated cerebellar dysplasia associated with Waardenburg syndrome (WS) and includes a review of cochlear implant outcomes in 42 WS patients. A 1-year-old male infant presented with speech delay, iris heterochromia, profound hearing loss, and an asymmetric, underdeveloped right occipital skull on CT imaging. Brain MRI demonstrated a hypoplastic right cerebellum, no hydrocephalus, normal auditory nerves and brainstem. He underwent successful bilateral sequential cochlear implantation. Cochlear implants remain a reasonable habilitative option for WS patients with congenital deafness, including those with cerebellar abnormalities.
2007-02-13 | The developmental biology of melanocytes and its application to understanding human congenital disorders of pigmentation.
In the past 15 years, a fruitful interplay between the description of mutations associated with human congenital disorders of pigmentation, the discovery of the molecular basis of murine coat color mutants, and the elucidation of determinants of melanocyte development from the neural crest has led to rapid advancement in the understanding of these disorders and the developmental biology underlying them. The insight gained about these human disorders from similar mouse models has facilitated progress that might not otherwise have occurred so rapidly. Clearly more work remains to be done, especially on the discovery of additional genes in humans that underlie the majority of WS2 cases not attributable to mutations in MITF. Sensitized genetic screens, using random mutagenesis in combination with existing mutant coat color alleles, may help uncover additional genes regulating melanocyte development in mice. Such studies would provide examples whose human homologues could be tested for mutations in patients who have pigmentation disorders that are currently unclassifiable. Intervention in developmental disorders is a challenging prospect. Nonetheless, it is imaginable that additional studies of the determinants of melanocyte survival during and after development could lead to strategies designed to maintain or replace functionally defective melanocytes, especially in localized regions such as the inner ear. The growing interest among investigators in the melanocyte as a model cellular system, with striking phenotypes across species, ensures that the field of melanocyte development and the studies of congenital disorders of pigmentation will remain vibrant in the foreseeable future.
proteins
2026-02-13 | SOX10 Mutation of Waardenburg Syndrome With Hypogonadism: A Report of 2 Cases.
Waardenburg syndrome (WS) is a complex genetic disorder primarily characterized by auditory and pigmentary abnormalities, resulting from neural crest cell migration disorders. We reported 2 genetically confirmed SOX10-mutant WS cases illustrating critical management principles. Both patients underwent early auditory intervention (case 1: cochlear implantation at age 3; case 2: hearing aids from age 2), resulting in preserved age-appropriate language acquisition. Each case manifested delayed puberty with biochemical evidence of hypogonadotropic hypogonadism, necessitating gonadotropin therapy to potentiate virilization and preserve fertility. Multidisciplinary care and emerging therapeutic approaches offer hope for better management. Further studies are warranted to improve the diagnosis, treatment, and quality of life of patients with WS.
2011-06-15 | The MADS box transcription factor MEF2C regulates melanocyte development and is a direct transcriptional target and partner of SOX10
Waardenburg syndromes are characterized by pigmentation and autosensory hearing defects, and mutations in genes encoding transcription factors that control neural crest specification and differentiation are often associated with Waardenburg and related disorders. For example, mutations in SOX10 result in a severe form of Waardenburg syndrome, Type IV, also known as Waardenburg-Hirschsprung disease, characterized by pigmentation and other neural crest defects, including defective innervation of the gut. SOX10 controls neural crest development through interactions with other transcription factors. The MADS box transcription factor MEF2C is an important regulator of brain, skeleton, lymphocyte and cardiovascular development and is required in the neural crest for craniofacial development. Here, we establish a novel role for MEF2C in melanocyte development. Inactivation of Mef2c in the neural crest of mice results in reduced expression of melanocyte genes during development and a significant loss of pigmentation at birth due to defective differentiation and reduced abundance of melanocytes. We identify a transcriptional enhancer of Mef2c that directs expression to the neural crest and its derivatives, including melanocytes, in transgenic mouse embryos. This novel Mef2c neural crest enhancer contains three functional SOX binding sites and a single essential MEF2 site. We demonstrate that Mef2c is a direct transcriptional target of SOX10 and MEF2 via this evolutionarily conserved enhancer. Furthermore, we show that SOX10 and MEF2C physically interact and function cooperatively to activate the Mef2c gene in a feed-forward transcriptional circuit, suggesting that MEF2C might serve as a potentiator of the transcriptional pathways affected in Waardenburg syndromes.
2001-03-29 | Regulation of Pax3 transcriptional activity by SUMO-1-modified PML.
Pax3 is an evolutionarily conserved transcription factor that plays a major role in a variety of developmental processes. Mutations in Pax3 lead to severe malformations as seen in human Waardenburg syndrome and in the Splotch mutant mice. The transcriptional activity of Pax3 was recently shown to be repressed by Daxx whereas the oncogenic fusion protein Pax3-FKHR is unresponsive to this repressive action. Here we demonstrate that Daxx-mediated repression of Pax3 can be inhibited by the nuclear body (NB)-associated protein PML. Interestingly, this suppression of Daxx properties correlates with its recruitment to the NBs. Factors such as arsenicals and interferons that enhance NB formation, trigger both the targeting of Daxx to these nuclear structures and the relief of the repressive activity of Daxx. Conversely, lack of structurally intact NBs profoundly impairs Pax3 transcriptional activity, likely by increasing the pool of available nucleoplasmic Daxx. Moreover, a PML mutant that can not be modified by the ubiquitin-related SUMO-1 modifier is no more able to interact with Daxx. Consistently, such a mutant fails both to inhibit the Daxx repressing effect on Pax3 and to induce its accumulation into the NBs. Taken together, these results argue that SUMO-1 modified PML can derepress Pax3 transcriptional activity through sequestration of the Daxx repressor into the NBs and suggest a role for these nuclear structures in the transcriptional control by Pax proteins. Oncogene (2001) 20, 1 - 9.
gene therapies
2025-10-27 | Mild features of partial PAX3 deletion in patients with prenatal Waardenburg syndrome: a case report and literature review.
Waardenburg syndrome (WS) is a group of autosomal dominant hereditary disorders characterized by auditory-pigmentary abnormalities. Haploinsufficiency of paired box 3 (PAX3) gene is one of the known pathogenic mechanisms. However, clinical phenotypes are difficult to predict precisely in fetuses harboring PAX3 haploinsufficiency. In this study, we report a family with a PAX3 deletion encompassing exons 1-4, in which clinical manifestations ranged from normal to mild abnormalities. A 22-year-old woman (gravida 2, para 0) was referred to our prenatal center at 18 weeks of gestation due to a history of congenital spina bifida in her previous pregnancy. Chromosomal analysis had been performed on fetal tissue from the terminated pregnancy and on amniotic fluid obtained during the current pregnancy. A rare partial deletion of PAX3 gene was identified and confirmed to be of paternal origin. A diagnosis of WS was established based on the clinical features of the father. However, the newborn from the second pregnancy exhibited normal phenotypes after birth. This work suggests that deletions encompassing the promoter and functional domains of PAX3 gene functionally represent a haploinsufficiency mechanism, which leads to variable clinical manifestations. These findings broaden our understanding of copy number variation analysis and genetic counseling in prenatal settings. In addition, PAX3 gene should be considered a candidate gene in cases presenting with auditory-pigmentary abnormalities or neural tube defects of unknown etiology.
2025-08-01 | Full length transcriptomic profiling reveals insights into the white coat phenotype in Waardenburg syndrome mice harboring the Mitf R324del mutation.
Waardenburg syndrome (WS) is distinguished by depigmented patches of hair and skin, striking blue eyes and sensorineural hearing loss. Studies on alternative splicing (AS) in the abnormal pigmentation in skin in WS are currently poorly understood. In this study, we conducted comprehensive full-length transcriptome sequencing analysis on abdominal skin tissues from mice harboring the Mitf p.R324del mutation and wild-type controls. Our analysis revealed 3619 differentially expressed genes (DEGs), with 1916 upregulated and 1703 downregulated. Notably, pigment-associated genes and related signaling pathways were significantly enriched. Additionally, we identified extensive AS events in the skin tissue of Mitf mutant mice, including 97 A3, 85 A5, 101 AF, 42 AL, 8 MX, 44 RI, and 184 SE events (P < 0.05), suggesting AS events may contribute to the pigment distribution patterns in Mitf p.R324del mutation mice. Furthermore, we observed downregulation of Dct, Mlana, and Snai2, which indicates that Mitf mutations disrupt neural crest cells into melanocytes, melanosome structure, and melanin biosynthesis. Overall, our results support that variation in gene expression and AS are important and complementary mechanisms governing pigmentation defects in WS.
2025-05-15 | The Diverse Genetic Landscape of Hearing Impairment in South African Families.
To elucidate the genetic etiology of hearing impairment (HI) in South Africa, 45 nonsyndromic HI (NSHI) and syndromic HI (SHI) families with ≥ 2 affected members were analyzed. Exome and sanger sequencing were used to identify causal genes. For NSHI, 14 of 24 families segregated variants in NSHI genes, that is, CDH23, GJB2, MITF, MYO7A, MYO15A, PCDH15, POU3F4, REST, SLC26A4, TMPRSS3, and WFS1. For the 21 SHI families, 14 have Waardenburg syndrome, two Branchio-Oto-Renal syndromes, and one each with Bartter, Chudley-McCullough, Deafness-Albinism, MYH9-related disorder, and Pendred syndromes. The cause of SHI was determined for 14 families, with EDN3, EDNRB, GPSM2, MITF, MYH9, SLC12A1, and SLC26A4 underlying the syndrome in a single family, EYA1 in two families, and PAX3 in five families. For the NSHI and SHI genes, 52.9% and 35.7% of the variants, respectively, have not been reported in disease etiology. Additionally, two Waardenburg families segregated variants in NSHI genes, BDP1 and MYO6, but these findings need to be validated. This study enhances the understanding of the genetic landscape of HI in South Africa, revealing a high level of locus and allelic heterogeneity. Studying diverse populations provides new insights into HI etiology that, in turn, can improve genetic diagnosis and personalized management.
2025-04-18 | A novel noncanonical splicing pathogenic variant in PAX3 associated with Waardenburg Syndrome type 1 in an Iranian family
Abstract Background Waardenburg syndrome type 1 (WS1) is an uncommon autosomal dominant (AD) genetic disorder. The primary cause of WS1 has been shown to be the pathogenic variants of PAX3 , which encodes a protein that belongs to the paired box family (Paired Box 3). Variable manifestations of sensorineural hearing impairment, pigmentation abnormalities, and other clinical signs have been observed in individuals with WS1. Here, we report an Iranian pedigree affected by WS1, which was caused by a novel pathogenic splicing variant in PAX3 . Materials and methods WS1 was diagnosed in a 5-year-old girl according to the Waardenburg Syndrome Consortium criteria. According to a thorough family history, four relatives were affected. Exome sequencing (ES), combined with Sanger sequencing, was used in genetic studies. Results We identified a novel noncanonical splicing variant, NM_181458.4: c.86-3C > G, in PAX3 . In addition, the patient’s father was heterozygous for this variant. Conclusions This study highlights phenotypic variability in Iranian WS1 patients and demonstrates that ES has enabled us to better understand genetic diagnosis and expand the range of WS1 genetic variants.
2024-04-27 | Clinical and Genetic Correlation in Neurocristopathies: Bridging a Precision Medicine Gap.
Neurocristopathies (NCPs) encompass a spectrum of disorders arising from issues during the formation and migration of neural crest cells (NCCs). NCCs undergo epithelial-mesenchymal transition (EMT) and upon key developmental gene deregulation, fetuses and neonates are prone to exhibit diverse manifestations depending on the affected area. These conditions are generally rare and often have a genetic basis, with many following Mendelian inheritance patterns, thus making them perfect candidates for precision medicine. Examples include cranial NCPs, like Goldenhar syndrome and Axenfeld-Rieger syndrome; cardiac-vagal NCPs, such as DiGeorge syndrome; truncal NCPs, like congenital central hypoventilation syndrome and Waardenburg syndrome; and enteric NCPs, such as Hirschsprung disease. Additionally, NCCs' migratory and differentiating nature makes their derivatives prone to tumors, with various cancer types categorized based on their NCC origin. Representative examples include schwannomas and pheochromocytomas. This review summarizes current knowledge of diseases arising from defects in NCCs' specification and highlights the potential of precision medicine to remedy a clinical phenotype by targeting the genotype, particularly important given that those affected are primarily infants and young children.
small molecules
2025-06-25 | [Mechanisms of enhanced noise susceptibility in waardenburg syndrome Sox10 p.S100Rfs*9 mutant mice].
Objective:To investigate the impact of Waardenburg syndrome（WS） -associated Sox10 p.S100Rfs*9 mutation on inner ear function and its mechanism in noise-induced hearing impairment. Methods:A mice model carrying the Sox10 p.S100Rfs*9 mutation was established using CRISPR-Cas9 gene editing technology. Auditory phenotypes were assessed under baseline conditions and after noise exposure（96 dB SPL, 2 hours）. Auditory brainstem response（ABR） tests were performed to evaluate hearing function, combined with immunofluorescence staining of cochlear basilar membrane whole-mounts to observe hair cells and ribbon synapses. Transcriptome sequencing was conducted to analyze molecular mechanisms. Results:Sox10 p.S100Rfs*9 heterozygous mice exhibited normal hearing thresholds with characteristic ventral pigmentation abnormalities under baseline conditions. Following noise exposure, mutant mice showed significantly higher ABR thresholds at 24 000 Hz compared to wild-type controls（[60.00±6.12]vs[48.13±4.28]dB SPL, P<0.000 1）, and a significant reduction in ribbon synapses（CtBP2-positive puncta） in the basal turn（[55.0±2.3]vs[64.8±3.3]per inner hair cell, P=0.006 6）, while hair cell morphology and number remained intact. Transcriptome analysis revealed altered expression of genes involved in immune regulation, membrane structures, ion channels, and neuroactive ligand-receptor interactions. Conclusion:The Sox10 p.S100Rfs*9 mutation does not alter baseline hearing function but significantly increases inner ear susceptibility to noise damage, primarily manifested as enhanced ribbon synapse vulnerability, especially in high-frequency regions. This gene-environment interaction reveals that Sox10 haploinsufficiency may compromise noise tolerance by affecting synaptic stability and inner ear protective mechanisms. These findings provide new perspectives on the phenotypic heterogeneity in WS patients and theoretical basis for individualized noise protection strategies for patients carrying SOX10 mutations.
2022-02-11 | Acetylation reprograms MITF target selectivity
Abstract The ability of transcription factors to discriminate between different classes of binding sites associated with specific biological functions underpins effective gene regulation in development and homeostasis. How this is achieved is poorly understood. The microphthalmia-associated transcription factor MITF is a lineage-survival oncogene that plays a crucial role in melanocyte development and melanoma. MITF suppresses invasion, reprograms metabolism and promotes both proliferation and differentiation. How MITF distinguishes between differentiation and proliferation-associated targets is unknown. Here we show that compared to many transcription factors MITF exhibits a very long (>100s) residence time which is reduced by p300/CBP-mediated MITF acetylation at K206. While K206 acetylation also decreases genome-wide MITF DNA-binding affinity, it preferentially directs DNA binding away from differentiation-associated CATGTG motifs toward CACGTG elements. The results reveal an acetylation-mediated switch that suppresses differentiation and provides a mechanistic explanation of why a human K206Q MITF mutation is associated with Waardenburg syndrome.
2021-04-05 | Expression of unfolded protein response markers in the pheochromocytoma with Waardenburg syndrome: a case report.
It is clinically emergent to further understand the pathological mechanism to advance therapeutic strategy for endocrine tumors. A high amount of secretory protein with tumorigenic triggers are thought to induce unfolded protein response in endoplasmic reticulum in endocrine tumors, but its evidence is limited. A 40-year-old woman had an approximately 10-year history of intermittent headaches. After the incidental detection of a mass in her right adrenal gland by CT scan, she was admitted to our hospital. She had been diagnosed as type 1 Waardenburg syndrome with the symptoms of dystopia canthorum, blue iris, and left sensorineural hearing loss. Urinary catecholamine levels were markedly elevated. 123I-MIBG scintigraphy showed uptake in the mass in her adrenal gland. After the adrenalectomy, her headaches disappeared and urinary catecholamine levels decreased to normal range within 2 weeks. Genome sequencing revealed germline mutation of c.A175T (p.Ile59Phe) in transcription factor PAX3 gene and somatic novel mutation of c.1893_1898del (p. Asp631_Leu633delinsGlu) in proto-oncogene RET in her pheochromocytoma. RNA expression levels of RET were increased 139 times in her pheochromocytoma compared with her normal adrenal gland. Those of unfolded protein response markers, Bip/GRP78, CHOP, ATF4, and ATF6, were also increased in the pheochromocytoma. We report a rare case of pheochromocytoma with type 1 Waardenburg syndrome. This is the first case to show the activation of unfolded protein response in the pheochromocytoma with the novel somatic mutation in RET gene. Our findings may support that unfolded protein response is activated in endocrine tumors, which potentially could be a candidate of therapeutic target.
2014-08-14 | Targeting melanocyte and melanoma stem cells by 8-hydroxy-2-dipropylaminotetralin
Monobenzyl ether of hydroquinone (MBEH) is cytotoxic towards melanocytes. Its treatment efficacy is limited by an inability to eradicate stem cells. By contrast, 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-DPAT) affects melanocyte stem cell survival. MBEH and 8-DPAT were added to melanocytes and melanoma cells to compare cytotoxicity. Stem cell content among viable cells was determined by fluorocytometry using markers CD34, Pax3, and CD271. Immunostaining was used to identify stem cells in skin explants treated with MBEH or 8-DPAT ex vivo. Mice were exposed to MBEH or 8-DPAT and scanned for depigmentation before harvesting skin. MBEH exposure prompted a relative increase in stem cells among cultured melanocytes and melanoma cells, as treatment preferentially eliminated differentiated cells and spared the stem cells. Viability of this remaining, enriched stem cell population was however rapidly reduced by exposure to 8-DPAT within melanocyte and melanoma cell cultures. In human skin explants, the abundance of melanocyte stem cells was also visibly reduced after 8-DPAT treatment, in contrast to tissue exposed to MBEH. Meanwhile, significant depigmentation of the mouse pelage and loss of differentiated melanocytes was observed in vivo in response to topical application of MBEH, but not 8-DPAT. Prolonged application of the latter agent instead appeared to effectively reduce the abundance of melanocyte stem cells in the dermis. This furthers the idea that MBEH and 8-DPAT target complementary cell populations. Results indicate that combination treatment may demonstrate superior therapeutic activity by eliminating both differentiated and tumor initiating populations.
2014-05-29 | [Hereditary hypomelanocytoses: the role of PAX3, SOX10, MITF, SNAI2, KIT, EDN3 and EDNRB genes].
Hypo- and hyperpigmentation disorders are the most severe dermatological diseases observed in patients from all over the world. These disorders can be divided into melanoses connected with disorders of melanocyte function and melanocytoses connected with melanocyte development. The article presents some hereditary hypomelanocytoses, which are caused by abnormal melanoblast development, migration and proliferation as well as by abnormal melanocyte viability and proliferation. These disorders are represented by Waardenburg syndrome, piebaldism and Tietz syndrome, and are caused by different mutations of various or the same genes. The types of mutations comprise missense and nonsense mutations, frameshifts (in-frame insertions or deletions), truncating variations, splice alterations and non-stop mutations. It has been demonstrated that mutations of the same gene may cause different hypopigmentation syndromes that may have similar phenotypes. For example, mutations of the MITF gene cause Waardenburg syndrome type 2A as well as Tietz syndrome. It has also been demonstrated that mutations of different genes may cause an identical syndrome. For example, mutations of MITF, SNAI2 and SOX10 genes are observed in Waardenburg syndrome type II and mutations of EDNRB, EDN3 and SOX10 genes are responsible for Waardenburg syndrome type IV. In turn, mutation of the KIT gene and/or heterozygous deletion of the SNAI2 gene result in piebaldism disease. The knowledge of the exact mechanisms of pigmentary disorders may be useful in the development of new therapeutic approaches to their treatment.
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