RARE DISEASE
Autosomal recessive dopa-responsive dystonia
Autosomal recessive dopa-responsive dystonia
Autosomal recessive dopa-responsive dystonia
Synonyms: Autosomal recessive Segawa syndrome, DYT5b, Tyrosine hydroxylase deficiency, Tyrosine hydroxylase-deficient dopa-responsive dystonia
Synonyms: Autosomal recessive Segawa syndrome, DYT5b, Tyrosine hydroxylase deficiency, Tyrosine hydroxylase-deficient dopa-responsive dystonia
Synonyms: Autosomal recessive Segawa syndrome, DYT5b, Tyrosine hydroxylase deficiency, Tyrosine hydroxylase-deficient dopa-responsive dystonia
Drug discovery
3
drugs
With orphan designations
Overview
Autosomal recessive dopa-responsive dystonia (DYT5b) is a rare neurometabolic disorder caused by tyrosine hydroxylase gene mutations, leading to catecholamine deficiency. It manifests in infancy with hypokinetic-rigid syndrome, dystonia, and autonomic disturbances. Two phenotypes exist: a classic levodopa-responsive form and a severe infantile encephalopathy with poor treatment response. Lifelong levodopa remains the cornerstone therapy, though severe cases often require careful dose titration [1][6][8].
Therapies
Categories: rare genetic diseases, rare inborn errors of metabolism, rare neurological diseases
Research Papers
41 drug discovery papers about Autosomal recessive dopa-responsive dystonia, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
41 drug discovery papers about Autosomal recessive dopa-responsive dystonia, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-04-28 | Korean Ginseng Ginsenoside Rg3 for Neurotransmitter Synthesis Enhancement
Ginsenoside Rg3 upregulates tyrosine hydroxylase and tryptophan hydroxylase expression through PKA-CREB signaling, compensating for reduced BH4 availability in 6-PTPS deficiency. The compound also enhances L-DOPA decarboxylase activity and promotes vesicular monoamine transporter function, improving overall catecholamine and serotonin synthesis efficiency.
2026-04-11 | Genetic analysis reveals phenotypic variability in three Colombian families with dopa-responsive dystonia: novel genotype-phenotype correlations
BACKGROUND: Dopa-responsive Dystonia (DRD) due to GTP cyclohydrolase 1 (GTPCH1) deficiency is a neurogenetic disorder caused by pathogenic GCH1 variants. Tetrahydrobiopterin (BH4) deficiency impairs dopamine synthesis in the basal ganglia, leading to childhood-onset dystonia with excellent response to levodopa. CASE PRESENTATION: We report eight patients from three unrelated families with GCH1 (NM_000161.3) variants: c.142 C > T; p.(Gln48*), c.241T > C; p.(Ser81Pro), and c.607G > A; p.(Gly203Arg). Two individuals homozygous for c.142 C > T showed phenotypic discordance. Mean age at onset was 7.3 years (range: 6–12), with an average diagnostic delay of 13.4 years. All symptomatic individuals responded well to low-dose levodopa. DISCUSSION: This is the first report to describe variable expressivity among individuals homozygous for p.(Gln48*). Previous literature has focused on heterozygous carriers with incomplete penetrance, and homozygous variability remains scarcely documented. CONCLUSIONS: Our findings expand the clinical and molecular spectrum of DRD and challenge the assumption that autosomal recessive GCH1 variants invariably cause a severe phenotype. This report underscores the importance of family-based genetic studies, detailed pedigrees, and careful clinical surveillance of asymptomatic carriers. A low threshold for levodopa trials is warranted, even when inheritance patterns or symptom severity deviate from classical expectations. These insights are critical to improving early recognition and timely treatment.
2025-11-14 | An Unusual Case of TH Mutation Presenting with Titubation: Movement Disorder
Introduction: Tyrosine hydroxylase (TH) is a key enzyme in catecholamine biosynthesis, playing a crucial role in dopamine (DOPA) production.Tyrosine hydroxylase deficiency has a broad clinical spectrum ranging from DOPA-responsive dystonia to severe infantile encephalopathy.Although classically presenting with hypokinesia, rigidity, and dystonia, atypical phenotypes can mimic other neurological disorders, often leading to misdiagnosis and delayed treatment.Case description: In a family of four, the patient's elder sister having an uneventful birth, had global developmental delay and presented as a cerebral palsy (CP) mimic, initial investigations and magnetic resonance imaging (MRI) Brain were normal, on suspicion of genetic abnormality, whole exome sequencing was done showing homozygous mutation in TH gene and DOPA trial was started, following which there is marked improvement.The patient, a 6-month-old male, had an uneventful birth, was neurodevelopmentally normal till 5 months of age, when parents noticed head titubation.Neurological examination revealed rhythmic oscillatory movements without signs of spasticity, dystonia, or developmental regression.more in the morning and increased crying, these movements also improved with a low dose of DOPA.Discussion: This case highlights an unusual presentation of TH deficiency with isolated titubation as an early sign.It underscores the expanding phenotypic variability of the disorder and the potential for misdiagnosis, particularly when the presentation deviates from classical motor findings.Early recognition and treatment with DOPA replacement can result in significant clinical recovery.Moreover, the presence of a similarly affected sibling earlier diagnosed as CP mimics emphasizes the need for heightened clinical suspicion and appropriate workup in familial cases of unexplained movement disorders.
2025-11-11 | Consensus Guideline for the Diagnosis and Treatment of Tyrosine Hydroxylase (TH) Deficiency.
Tyrosine hydroxylase (TH) catalyses the rate-limiting step in dopamine biosynthesis. Autosomal recessive tyrosine hydroxylase deficiency (THD) leads to clinical phenotypes reflecting the deficiency of dopamine, norepinephrine, or epinephrine in the central nervous system (CNS), presenting along a continuous spectrum from mild to severe forms of the disease. The diagnosis is suggested by the detection of low CSF homovanillic acid (HVA) and confirmed by identifying biallelic pathogenic variants in the TH gene. L-dopa/decarboxylase inhibitor (DCI) supplementation is often the first-line treatment, and most patients have a good therapeutic response. However, initiation of therapy can be challenging in patients with severe disease forms who develop L-dopa/DCI-induced dyskinesia. Therefore, alternative treatment options, such as monoamine oxidase (MAO) inhibitors, must be evaluated to optimize motor symptom control. Clinical experience suggests that early diagnosis and treatment initiation may improve the outcome. Additionally, a multidisciplinary treatment approach should be utilized to monitor neurocognitive development and other comorbidities that may occur in THD. In this consensus guideline, representatives of the International Working Group on Neurotransmitter related Disorders (iNTD) and patient advocates evaluated all the evidence available in the literature on the diagnosis and management of THD and developed recommendations using the SIGN and GRADE methodologies. Based on the limited evidence, practical recommendations have been developed to support clinical diagnosis, laboratory testing, neuroimaging, medical treatment, and non-medical interventions. Research topics for further development were identified. This guideline aims to improve the care of patients with THD worldwide and raise general awareness of this rare disease.
2025-10-22 | Phenotypic, Genotypic Characteristics, and Treatment Strategies of Pediatric Tyrosine Hydroxylase Deficiency: A Single-Center Retrospective Analysis of 51 Cases.
Tyrosine hydroxylase deficiency (THD) is a rare autosomal recessive disorder caused by impaired catecholamine biosynthesis in the brain. The rarity and heterogeneous clinical spectrum of THD often lead to misdiagnosis, and evidence-based, genotype-specific levodopa dosing protocols remain unavailable. To delineate the clinical spectrum, genetic variants, and levodopa response in a large single-center cohort of Chinese pediatric THD patients, and to explore genotype-specific dosing requirements. A retrospective analysis was performed on 51 pediatric patients diagnosed with THD at a single center in China. Data on genotype, phenotype, and treatment outcomes were reviewed. Movement disorders were present in 96.1% of cases, with developmental delay observed in 88.2%, and autonomic symptoms in 51.0%. Among the 36 identified variants, the predominant were p.R233H (37.3%), p.R153X (10.8%), and p.Q232X (6.9%). Among the 13 p.R233H carriers who showed a good response to levodopa, those with a nonsense second allele (n = 5) required a significantly higher mean levodopa dose than those with a missense second allele (n = 8) (P = 0.03). This study is the largest retrospective analysis of pediatric THD patients from a single-ethnicity cohort, summarizing the clinical and genotypic characteristics. Variant type-particularly R233H/nonsense versus R233H/missense significantly influences dose requirements, underscoring the value of genotype-guided, dynamic levodopa titration to optimize long-term outcomes.
proteins
2025-03-20 | Structural recognition and stabilization of tyrosine hydroxylase by the J-domain protein DNAJC12
Pathogenic variants of the J-domain protein DNAJC12 cause parkinsonism, which is associated with a defective interaction of DNAJC12 with tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis. In this work, we characterize the formation of the TH:DNAJC12 complex, showing that DNAJC12 binding stabilizes both TH and the variant TH-p.R202H, associated with TH deficiency. This binding delays their time-dependent aggregation in an Hsp70-independent manner, while preserving TH activity and feedback regulatory inhibition by dopamine. DNAJC12 alone barely activates Hsc70 but synergistically stimulates Hsc70 ATPase activity when complexed with TH. Cryo-electron microscopy supported by crosslinking-mass spectroscopy reveals two DNAJC12 monomers bound per TH tetramer, each embracing one of the two regulatory domain dimers, leaving the active sites available for substrate, cofactor and inhibitory dopamine interaction. Our results also reveal the key role of the C-terminal region of DNAJC12 in TH binding, explaining the pathogenic mechanism of the DNAJC12 disease variant p.W175Ter.
2018-11-27 | Translational effects and coding potential of an upstream open reading frame associated with DOPA Responsive Dystonia.
Upstream open reading frames (uORFs) have emerged as major post-transcriptional regulatory elements in eukaryotic species. In general, uORFs are initiated by a translation start codon within the 5' untranslated region of a gene (upstream ATG; uATG), and they are negatively correlated with translational efficiency. In addition to their translational regulatory role, some uORFs can code for biologically active short peptides. The importance of uATGs/uORFs is further underscored by human diseases associated with single nucleotide polymorphisms (SNPs), which disrupt existing uORFs or introduce novel uORFs. Although several functional proteins translated from naturally occurring uORFs have been described, the coding potential of uORFs created by SNPs has been ignored because of the a priori assumption that these proteins are short-lived with no likely impact on protein homeostasis. Thus, studies on SNP-created uORFs are limited to their translational effects, leaving unexplored the potential cellular consequences of a SNP/uORF-encoded protein. Here, we investigate functionality of a uATG/uORF introduced by a +142C>T SNP within the GCH1 gene and associated with a familial form of DOPA Responsive Dystonia. We report that the +142C>T SNP represses GCH1 translation, and introduces a short, frame shifted uORF that encodes a 73-amino acid peptide. This peptide is localized within the nucleus and compromises cell viability upon proteasome inhibition. Our work extends the list of uATG/uORF associated diseases and advances research on peptides translated from SNP-introduced uORFs, a neglected component of the proteome.
small molecules
2026-04-28 | Korean Ginseng Ginsenoside Rg3 for Neurotransmitter Synthesis Enhancement
Ginsenoside Rg3 upregulates tyrosine hydroxylase and tryptophan hydroxylase expression through PKA-CREB signaling, compensating for reduced BH4 availability in 6-PTPS deficiency. The compound also enhances L-DOPA decarboxylase activity and promotes vesicular monoamine transporter function, improving overall catecholamine and serotonin synthesis efficiency.
2026-04-11 | Genetic analysis reveals phenotypic variability in three Colombian families with dopa-responsive dystonia: novel genotype-phenotype correlations
BACKGROUND: Dopa-responsive Dystonia (DRD) due to GTP cyclohydrolase 1 (GTPCH1) deficiency is a neurogenetic disorder caused by pathogenic GCH1 variants. Tetrahydrobiopterin (BH4) deficiency impairs dopamine synthesis in the basal ganglia, leading to childhood-onset dystonia with excellent response to levodopa. CASE PRESENTATION: We report eight patients from three unrelated families with GCH1 (NM_000161.3) variants: c.142 C > T; p.(Gln48*), c.241T > C; p.(Ser81Pro), and c.607G > A; p.(Gly203Arg). Two individuals homozygous for c.142 C > T showed phenotypic discordance. Mean age at onset was 7.3 years (range: 6–12), with an average diagnostic delay of 13.4 years. All symptomatic individuals responded well to low-dose levodopa. DISCUSSION: This is the first report to describe variable expressivity among individuals homozygous for p.(Gln48*). Previous literature has focused on heterozygous carriers with incomplete penetrance, and homozygous variability remains scarcely documented. CONCLUSIONS: Our findings expand the clinical and molecular spectrum of DRD and challenge the assumption that autosomal recessive GCH1 variants invariably cause a severe phenotype. This report underscores the importance of family-based genetic studies, detailed pedigrees, and careful clinical surveillance of asymptomatic carriers. A low threshold for levodopa trials is warranted, even when inheritance patterns or symptom severity deviate from classical expectations. These insights are critical to improving early recognition and timely treatment.
2025-11-14 | An Unusual Case of TH Mutation Presenting with Titubation: Movement Disorder
Introduction: Tyrosine hydroxylase (TH) is a key enzyme in catecholamine biosynthesis, playing a crucial role in dopamine (DOPA) production.Tyrosine hydroxylase deficiency has a broad clinical spectrum ranging from DOPA-responsive dystonia to severe infantile encephalopathy.Although classically presenting with hypokinesia, rigidity, and dystonia, atypical phenotypes can mimic other neurological disorders, often leading to misdiagnosis and delayed treatment.Case description: In a family of four, the patient's elder sister having an uneventful birth, had global developmental delay and presented as a cerebral palsy (CP) mimic, initial investigations and magnetic resonance imaging (MRI) Brain were normal, on suspicion of genetic abnormality, whole exome sequencing was done showing homozygous mutation in TH gene and DOPA trial was started, following which there is marked improvement.The patient, a 6-month-old male, had an uneventful birth, was neurodevelopmentally normal till 5 months of age, when parents noticed head titubation.Neurological examination revealed rhythmic oscillatory movements without signs of spasticity, dystonia, or developmental regression.more in the morning and increased crying, these movements also improved with a low dose of DOPA.Discussion: This case highlights an unusual presentation of TH deficiency with isolated titubation as an early sign.It underscores the expanding phenotypic variability of the disorder and the potential for misdiagnosis, particularly when the presentation deviates from classical motor findings.Early recognition and treatment with DOPA replacement can result in significant clinical recovery.Moreover, the presence of a similarly affected sibling earlier diagnosed as CP mimics emphasizes the need for heightened clinical suspicion and appropriate workup in familial cases of unexplained movement disorders.
2025-11-11 | Consensus Guideline for the Diagnosis and Treatment of Tyrosine Hydroxylase (TH) Deficiency.
Tyrosine hydroxylase (TH) catalyses the rate-limiting step in dopamine biosynthesis. Autosomal recessive tyrosine hydroxylase deficiency (THD) leads to clinical phenotypes reflecting the deficiency of dopamine, norepinephrine, or epinephrine in the central nervous system (CNS), presenting along a continuous spectrum from mild to severe forms of the disease. The diagnosis is suggested by the detection of low CSF homovanillic acid (HVA) and confirmed by identifying biallelic pathogenic variants in the TH gene. L-dopa/decarboxylase inhibitor (DCI) supplementation is often the first-line treatment, and most patients have a good therapeutic response. However, initiation of therapy can be challenging in patients with severe disease forms who develop L-dopa/DCI-induced dyskinesia. Therefore, alternative treatment options, such as monoamine oxidase (MAO) inhibitors, must be evaluated to optimize motor symptom control. Clinical experience suggests that early diagnosis and treatment initiation may improve the outcome. Additionally, a multidisciplinary treatment approach should be utilized to monitor neurocognitive development and other comorbidities that may occur in THD. In this consensus guideline, representatives of the International Working Group on Neurotransmitter related Disorders (iNTD) and patient advocates evaluated all the evidence available in the literature on the diagnosis and management of THD and developed recommendations using the SIGN and GRADE methodologies. Based on the limited evidence, practical recommendations have been developed to support clinical diagnosis, laboratory testing, neuroimaging, medical treatment, and non-medical interventions. Research topics for further development were identified. This guideline aims to improve the care of patients with THD worldwide and raise general awareness of this rare disease.
2025-10-22 | Phenotypic, Genotypic Characteristics, and Treatment Strategies of Pediatric Tyrosine Hydroxylase Deficiency: A Single-Center Retrospective Analysis of 51 Cases.
Tyrosine hydroxylase deficiency (THD) is a rare autosomal recessive disorder caused by impaired catecholamine biosynthesis in the brain. The rarity and heterogeneous clinical spectrum of THD often lead to misdiagnosis, and evidence-based, genotype-specific levodopa dosing protocols remain unavailable. To delineate the clinical spectrum, genetic variants, and levodopa response in a large single-center cohort of Chinese pediatric THD patients, and to explore genotype-specific dosing requirements. A retrospective analysis was performed on 51 pediatric patients diagnosed with THD at a single center in China. Data on genotype, phenotype, and treatment outcomes were reviewed. Movement disorders were present in 96.1% of cases, with developmental delay observed in 88.2%, and autonomic symptoms in 51.0%. Among the 36 identified variants, the predominant were p.R233H (37.3%), p.R153X (10.8%), and p.Q232X (6.9%). Among the 13 p.R233H carriers who showed a good response to levodopa, those with a nonsense second allele (n = 5) required a significantly higher mean levodopa dose than those with a missense second allele (n = 8) (P = 0.03). This study is the largest retrospective analysis of pediatric THD patients from a single-ethnicity cohort, summarizing the clinical and genotypic characteristics. Variant type-particularly R233H/nonsense versus R233H/missense significantly influences dose requirements, underscoring the value of genotype-guided, dynamic levodopa titration to optimize long-term outcomes.
proteins
2025-03-20 | Structural recognition and stabilization of tyrosine hydroxylase by the J-domain protein DNAJC12
Pathogenic variants of the J-domain protein DNAJC12 cause parkinsonism, which is associated with a defective interaction of DNAJC12 with tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis. In this work, we characterize the formation of the TH:DNAJC12 complex, showing that DNAJC12 binding stabilizes both TH and the variant TH-p.R202H, associated with TH deficiency. This binding delays their time-dependent aggregation in an Hsp70-independent manner, while preserving TH activity and feedback regulatory inhibition by dopamine. DNAJC12 alone barely activates Hsc70 but synergistically stimulates Hsc70 ATPase activity when complexed with TH. Cryo-electron microscopy supported by crosslinking-mass spectroscopy reveals two DNAJC12 monomers bound per TH tetramer, each embracing one of the two regulatory domain dimers, leaving the active sites available for substrate, cofactor and inhibitory dopamine interaction. Our results also reveal the key role of the C-terminal region of DNAJC12 in TH binding, explaining the pathogenic mechanism of the DNAJC12 disease variant p.W175Ter.
2018-11-27 | Translational effects and coding potential of an upstream open reading frame associated with DOPA Responsive Dystonia.
Upstream open reading frames (uORFs) have emerged as major post-transcriptional regulatory elements in eukaryotic species. In general, uORFs are initiated by a translation start codon within the 5' untranslated region of a gene (upstream ATG; uATG), and they are negatively correlated with translational efficiency. In addition to their translational regulatory role, some uORFs can code for biologically active short peptides. The importance of uATGs/uORFs is further underscored by human diseases associated with single nucleotide polymorphisms (SNPs), which disrupt existing uORFs or introduce novel uORFs. Although several functional proteins translated from naturally occurring uORFs have been described, the coding potential of uORFs created by SNPs has been ignored because of the a priori assumption that these proteins are short-lived with no likely impact on protein homeostasis. Thus, studies on SNP-created uORFs are limited to their translational effects, leaving unexplored the potential cellular consequences of a SNP/uORF-encoded protein. Here, we investigate functionality of a uATG/uORF introduced by a +142C>T SNP within the GCH1 gene and associated with a familial form of DOPA Responsive Dystonia. We report that the +142C>T SNP represses GCH1 translation, and introduces a short, frame shifted uORF that encodes a 73-amino acid peptide. This peptide is localized within the nucleus and compromises cell viability upon proteasome inhibition. Our work extends the list of uATG/uORF associated diseases and advances research on peptides translated from SNP-introduced uORFs, a neglected component of the proteome.
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Drug Discovery Landscape
3 orphan drug designations for Autosomal recessive dopa-responsive dystonia, including 2 approved therapies.
3 orphan drug designations for Autosomal recessive dopa-responsive dystonia, including 2 approved therapies.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
Botulinum toxin type A [Dysport] | — | FDA | Approved | Ipsen Biopharmaceuticals, Inc. |
L-baclofen | — | FDA | — | Osmotica Pharmaceutical Corp. |
botulinum toxin type A [Botox] | — | FDA | Approved | Allergan, Inc. |
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