RARE DISEASE
Mucopolysaccharidosis type 4
Mucopolysaccharidosis type 4
Mucopolysaccharidosis type 4
Synonyms: MPS4, MPSIV, Morquio disease, Mucopolysaccharidosis type IV
Synonyms: MPS4, MPSIV, Morquio disease, Mucopolysaccharidosis type IV
Synonyms: MPS4, MPSIV, Morquio disease, Mucopolysaccharidosis type IV
Drug discovery
1
drug
With orphan designation
Overview
Mucopolysaccharidosis type IV (MPS IV/Morquio syndrome) is an autosomal recessive lysosomal storage disorder caused by deficient GALNS (IVA) or GLB1 (IVB) enzymes, leading to keratan/chondroitin sulfate accumulation. It manifests with severe skeletal dysplasia, short stature, spinal instability, joint hypermobility, cardiopulmonary compromise, and corneal clouding, while preserving cognition. Life-threatening complications include cervical spinal cord compression and tracheal obstruction [1][11][12][15].
Therapies
IVA: Weekly IV elosulfase alfa (ERT) improves endurance/respiratory function [6][8][13]; hematopoietic stem cell transplantation (HSCT) has limited skeletal benefits [8][16]
Surgical: Spinal fusion for cervical instability, tracheal reconstruction, and joint surgeries [8][12][17]
Supportive: Multidisciplinary care for respiratory, cardiac, and pain management [8][12][15]
Categories: rare bone diseases, rare developmental anomalies during embryogenesis, rare genetic diseases, rare inborn errors of metabolism, rare ophthalmic disorders, rare transplant-related disorders
Research Papers
230 drug discovery papers about Mucopolysaccharidosis type 4, with 5 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
230 drug discovery papers about Mucopolysaccharidosis type 4, with 5 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
2026-07-27 | Early Versus Late Enzyme Replacement Therapy in Siblings With Morquio A Syndrome: Insights Into Therapeutic Timing.
Enzyme replacement therapy (ERT) with elosulfase alfa is the only approved treatment for mucopolysaccharidosis type IVA. This case report delineates the 5-year outcomes of ERT in two Korean siblings with mucopolysaccharidosis type IVA, with the younger sibling initiating treatment at 0.8 years of age and the older one at 5.4 years. Both patients exhibited a progressive decline in their height standard deviation scores, with trajectories paralleling the natural history curves of the disease. At 5.2 years of age, persistent skeletal dysplasia was evident in both siblings. However, the younger sibling demonstrated attenuated disease severity, lacking cervical myelopathy or spinal stenosis requiring C1 laminoplasty. Cardiorespiratory assessment revealed normalized left ventricular mass index z-scores, stable ejection fractions, and the absence of valvular pathology. Overall, these findings suggest that early ERT attenuates severe spinal and upper body manifestations but does not prevent lower limb skeletal progression, highlighting the need for early therapeutic initiation along with orthopedic intervention to preserve cardiorespiratory parameters and functional independence.
2026-05-04 | Development of Small-Molecule Allosteric Modulators of Beta-Galactosidase (β-Gal) for the Treatment of GM1 Gangliosidosis and Morquio B.
GM1 gangliosidosis and Morquio B are rare lysosomal storage disorders (LSDs) with significant unmet medical needs. These disorders result from mutations in the galactosidase beta 1 (GLB1) gene, leading to impaired β-galactosidase (β-Gal) activity and toxic substrate accumulation. The lack of approved disease-modifying therapies for GM1 gangliosidosis and Morquio B, along with the challenges of achieving effective central nervous system delivery, has driven interest in small-molecule pharmacological chaperones (PCs) to restore β-Gal stability and function. Using Gain Therapeutics' Magellan™ platform, a novel allosteric binding site on β-Gal was identified, enabling the discovery of a new class of Structurally Targeted Allosteric Regulators (STARs). Medicinal chemistry optimization produced a structurally unique STAR compound series, demonstrating broad β-Gal stabilizing effects. The therapeutic potential of these compounds was evaluated in vitro using a canine fibroblast model of GM1 gangliosidosis, where they were shown to significantly reduce toxic GM1 ganglioside accumulation. Immunocytochemistry-based assays confirmed substrate clearance and provided reliable structure-activity relationships, guiding further compound development. Notably, STARs achieved greater substrate clearance than the competitive PC N-nonyl-deoxygalactonojirimycin (NN-DGJ) under the conditions tested, as demonstrated by immunocytochemistry-based assays. While these findings are encouraging, further in vivo studies are required to validate the therapeutic efficacy of these few STAR compounds, particularly in addressing the neurodegenerative aspects of GM1 gangliosidosis. This study underscores the potential of the Magellan platform in identifying STAR molecules and provides a strong foundation for further optimization and preclinical validation in GLB1-related disorders, particularly GM1 gangliosidosis.
2026-04-28 | Long-Term Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Mucopolysaccharidosis IVA: A 10-Year Follow-Up from a Single-Center Experience in China.
Allogeneic hematopoietic stem cell transplantation (HSCT) is a potential approach for pediatric mucopolysaccharidosis IVA (MPS IVA). However, delayed diagnosis and higher transplant-related complications have limited its broader use. This study investigated treatment-related benefit and up to 10-year outcomes following HSCT in children with MPS IVA. Study Design We retrospectively analyzed 19 pediatric patients with a severe phenotype of MPS IVA who underwent HSCT between January 2015 and July 2025. N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity, height growth, and organ dysfunction (cardiac, auditory, and visual) was evaluated to analyze the benefit of HSCT. The donor sources include human leukocyte antigen (HLA)-matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT, n = 5), HLA-matched unrelated donor PBSCT (MUD-PBSCT, n = 7), and single-unit unrelated umbilical cord blood transplantation (UD-UCBT, n = 7). The overall survival rate was 94.7% (18/19), apart from 1 mortality due to pulmonary infection. All surviving patients achieved full donor engraftment and durable restoration of GALNS activity. There is no severe graft-versus-host disease (GVHD) was observed. The majority of patients exhibited no deterioration in auditory, visual, respiratory, or cardiac function. During the long-term follow-up period, our cases showed a continued linear growth post-HSCT. Here we demonstrated the data of our HSCT experience in MPS IVA with the safety and efficacy of HSCT. More data with an expanded patient cohort are imperative to delineate the capacity of HSCT to repair severe skeletal manifestations in MPS IVA.
2026-03-30 | Ultrasound-guided one-point puncture lumbosacral plexus block combined with laryngeal mask airway general anesthesia for thigh amputation in a patient with mucopolysaccharidosis: a case report.
Mucopolysaccharidosis (MPS) is a group of rare inherited lysosomal storage disorders caused by deficiencies of specific enzymes, leading to abnormal accumulation of glycosaminoglycans in tissues throughout the body. It is often associated with a difficult airway, cervical spine instability, restrictive pulmonary dysfunction, and cardiovascular pathologies, which significantly increase perioperative risks. This manuscript reports a case of a 36-year-old male MPS patient (clinical phenotype highly suggestive of type IV) who underwent right mid-to-upper thigh amputation for a pathological fracture of the right femur. Given his potential difficult airway (Mallampati class III, thyromental distance <6 cm), mild kyphosis, and restrictive pulmonary dysfunction, the anesthetic plan consisted of an ultrasound-guided one-point puncture, dual-target lumbosacral plexus block (35 mL of 0.15% ropivacaine) combined with supraglottic airway (laryngeal mask airway, LMA) under general anesthesia. The block successfully provided an L2-S3 sensory level and served as the basis for postoperative multimodal analgesia. The surgery lasted 2 h with 500 mL blood loss, requiring 2 units of red blood cells. Hemodynamics remained stable, and no additional muscle relaxants were administered. The patient regained consciousness and the LMA was removed 10 min postoperatively. The Numerical Rating Scale (NRS) pain scores at 2, 6, 12, and 24 h postoperatively were 2, 3, 2, and 1, respectively. Functional exercise began on postoperative day 1 without major complications. The patient was discharged 15 days after surgery and was hospitalized for a total of 18 days. With strict patient selection and thorough preparation of emergency airway protocols, combining an LMA with an ultrasound-guided one-point puncture lumbosacral plexus block can be a safe and feasible individualized anesthetic strategy for lower limb proximal surgery in MPS patients. This approach helps avoid intubation risks, reduces opioid consumption, and promotes early recovery. However, due to the considerable difficulty of airway management in patients with MPS, elective surgery requires multidisciplinary consultation and comprehensive airway assessment to ensure perioperative safety.
2026-03-14 | AAV Gene Therapy for MPS IVA with Induction of Immune Tolerance via Oral Administration of Epitope Peptides of N-Acetylgalactosamine-6-sulfate Sulfatase.
Mucopolysaccharidosis IVA (MPS IVA) is caused by the accumulation of undegraded glycosaminoglycans due to the deficiency of the N-acetylgalactosamine-6-sulfate sulfatase (GALNS) enzyme. MPS IVA manifests as progressive systemic skeletal dysplasia. Gene therapy (GT) is potentially a one-time treatment in which the enzyme is continuously produced, circulated, and delivered to target tissues. However, immune responses to gene products can diminish therapeutic efficacy. We hypothesized that oral delivery of tolerogenic peptides induces immune tolerance to human GALNS (hGALNS) in MPS IVA mice, enhancing therapeutic efficacy. Neonatal mice deficient in mouse GALNS (mGALNS) were treated orally with three T-cell/B-cell epitope peptides or hGALNS protein on alternate days from day 3 after birth to day 20 before intravenous injection with AAV9 vectors encoding human GALNS on day 30. The results are encouraging, with anti-hGALNS antibodies undetectable in the plasma of orally administered peptide groups. hGALNS enzyme activities in plasma and tissues were higher in the orally treated groups than in the non-tolerized control group. Keratan sulfate levels in plasma, liver, and bone were normalized. Complete correction for heart vacuolization was achieved in peptide-treated groups, and partial correction for bone pathology was observed in all GT-treated groups. Overall, oral tolerance induction using immunodominant peptides promises to significantly enhance the efficacy of AAV-GT for MPS IVA.
2026-07-27 | Early Versus Late Enzyme Replacement Therapy in Siblings With Morquio A Syndrome: Insights Into Therapeutic Timing.
Enzyme replacement therapy (ERT) with elosulfase alfa is the only approved treatment for mucopolysaccharidosis type IVA. This case report delineates the 5-year outcomes of ERT in two Korean siblings with mucopolysaccharidosis type IVA, with the younger sibling initiating treatment at 0.8 years of age and the older one at 5.4 years. Both patients exhibited a progressive decline in their height standard deviation scores, with trajectories paralleling the natural history curves of the disease. At 5.2 years of age, persistent skeletal dysplasia was evident in both siblings. However, the younger sibling demonstrated attenuated disease severity, lacking cervical myelopathy or spinal stenosis requiring C1 laminoplasty. Cardiorespiratory assessment revealed normalized left ventricular mass index z-scores, stable ejection fractions, and the absence of valvular pathology. Overall, these findings suggest that early ERT attenuates severe spinal and upper body manifestations but does not prevent lower limb skeletal progression, highlighting the need for early therapeutic initiation along with orthopedic intervention to preserve cardiorespiratory parameters and functional independence.
2026-05-04 | Development of Small-Molecule Allosteric Modulators of Beta-Galactosidase (β-Gal) for the Treatment of GM1 Gangliosidosis and Morquio B.
GM1 gangliosidosis and Morquio B are rare lysosomal storage disorders (LSDs) with significant unmet medical needs. These disorders result from mutations in the galactosidase beta 1 (GLB1) gene, leading to impaired β-galactosidase (β-Gal) activity and toxic substrate accumulation. The lack of approved disease-modifying therapies for GM1 gangliosidosis and Morquio B, along with the challenges of achieving effective central nervous system delivery, has driven interest in small-molecule pharmacological chaperones (PCs) to restore β-Gal stability and function. Using Gain Therapeutics' Magellan™ platform, a novel allosteric binding site on β-Gal was identified, enabling the discovery of a new class of Structurally Targeted Allosteric Regulators (STARs). Medicinal chemistry optimization produced a structurally unique STAR compound series, demonstrating broad β-Gal stabilizing effects. The therapeutic potential of these compounds was evaluated in vitro using a canine fibroblast model of GM1 gangliosidosis, where they were shown to significantly reduce toxic GM1 ganglioside accumulation. Immunocytochemistry-based assays confirmed substrate clearance and provided reliable structure-activity relationships, guiding further compound development. Notably, STARs achieved greater substrate clearance than the competitive PC N-nonyl-deoxygalactonojirimycin (NN-DGJ) under the conditions tested, as demonstrated by immunocytochemistry-based assays. While these findings are encouraging, further in vivo studies are required to validate the therapeutic efficacy of these few STAR compounds, particularly in addressing the neurodegenerative aspects of GM1 gangliosidosis. This study underscores the potential of the Magellan platform in identifying STAR molecules and provides a strong foundation for further optimization and preclinical validation in GLB1-related disorders, particularly GM1 gangliosidosis.
2026-04-28 | Long-Term Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Mucopolysaccharidosis IVA: A 10-Year Follow-Up from a Single-Center Experience in China.
Allogeneic hematopoietic stem cell transplantation (HSCT) is a potential approach for pediatric mucopolysaccharidosis IVA (MPS IVA). However, delayed diagnosis and higher transplant-related complications have limited its broader use. This study investigated treatment-related benefit and up to 10-year outcomes following HSCT in children with MPS IVA. Study Design We retrospectively analyzed 19 pediatric patients with a severe phenotype of MPS IVA who underwent HSCT between January 2015 and July 2025. N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity, height growth, and organ dysfunction (cardiac, auditory, and visual) was evaluated to analyze the benefit of HSCT. The donor sources include human leukocyte antigen (HLA)-matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT, n = 5), HLA-matched unrelated donor PBSCT (MUD-PBSCT, n = 7), and single-unit unrelated umbilical cord blood transplantation (UD-UCBT, n = 7). The overall survival rate was 94.7% (18/19), apart from 1 mortality due to pulmonary infection. All surviving patients achieved full donor engraftment and durable restoration of GALNS activity. There is no severe graft-versus-host disease (GVHD) was observed. The majority of patients exhibited no deterioration in auditory, visual, respiratory, or cardiac function. During the long-term follow-up period, our cases showed a continued linear growth post-HSCT. Here we demonstrated the data of our HSCT experience in MPS IVA with the safety and efficacy of HSCT. More data with an expanded patient cohort are imperative to delineate the capacity of HSCT to repair severe skeletal manifestations in MPS IVA.
2026-03-30 | Ultrasound-guided one-point puncture lumbosacral plexus block combined with laryngeal mask airway general anesthesia for thigh amputation in a patient with mucopolysaccharidosis: a case report.
Mucopolysaccharidosis (MPS) is a group of rare inherited lysosomal storage disorders caused by deficiencies of specific enzymes, leading to abnormal accumulation of glycosaminoglycans in tissues throughout the body. It is often associated with a difficult airway, cervical spine instability, restrictive pulmonary dysfunction, and cardiovascular pathologies, which significantly increase perioperative risks. This manuscript reports a case of a 36-year-old male MPS patient (clinical phenotype highly suggestive of type IV) who underwent right mid-to-upper thigh amputation for a pathological fracture of the right femur. Given his potential difficult airway (Mallampati class III, thyromental distance <6 cm), mild kyphosis, and restrictive pulmonary dysfunction, the anesthetic plan consisted of an ultrasound-guided one-point puncture, dual-target lumbosacral plexus block (35 mL of 0.15% ropivacaine) combined with supraglottic airway (laryngeal mask airway, LMA) under general anesthesia. The block successfully provided an L2-S3 sensory level and served as the basis for postoperative multimodal analgesia. The surgery lasted 2 h with 500 mL blood loss, requiring 2 units of red blood cells. Hemodynamics remained stable, and no additional muscle relaxants were administered. The patient regained consciousness and the LMA was removed 10 min postoperatively. The Numerical Rating Scale (NRS) pain scores at 2, 6, 12, and 24 h postoperatively were 2, 3, 2, and 1, respectively. Functional exercise began on postoperative day 1 without major complications. The patient was discharged 15 days after surgery and was hospitalized for a total of 18 days. With strict patient selection and thorough preparation of emergency airway protocols, combining an LMA with an ultrasound-guided one-point puncture lumbosacral plexus block can be a safe and feasible individualized anesthetic strategy for lower limb proximal surgery in MPS patients. This approach helps avoid intubation risks, reduces opioid consumption, and promotes early recovery. However, due to the considerable difficulty of airway management in patients with MPS, elective surgery requires multidisciplinary consultation and comprehensive airway assessment to ensure perioperative safety.
2026-03-14 | AAV Gene Therapy for MPS IVA with Induction of Immune Tolerance via Oral Administration of Epitope Peptides of N-Acetylgalactosamine-6-sulfate Sulfatase.
Mucopolysaccharidosis IVA (MPS IVA) is caused by the accumulation of undegraded glycosaminoglycans due to the deficiency of the N-acetylgalactosamine-6-sulfate sulfatase (GALNS) enzyme. MPS IVA manifests as progressive systemic skeletal dysplasia. Gene therapy (GT) is potentially a one-time treatment in which the enzyme is continuously produced, circulated, and delivered to target tissues. However, immune responses to gene products can diminish therapeutic efficacy. We hypothesized that oral delivery of tolerogenic peptides induces immune tolerance to human GALNS (hGALNS) in MPS IVA mice, enhancing therapeutic efficacy. Neonatal mice deficient in mouse GALNS (mGALNS) were treated orally with three T-cell/B-cell epitope peptides or hGALNS protein on alternate days from day 3 after birth to day 20 before intravenous injection with AAV9 vectors encoding human GALNS on day 30. The results are encouraging, with anti-hGALNS antibodies undetectable in the plasma of orally administered peptide groups. hGALNS enzyme activities in plasma and tissues were higher in the orally treated groups than in the non-tolerized control group. Keratan sulfate levels in plasma, liver, and bone were normalized. Complete correction for heart vacuolization was achieved in peptide-treated groups, and partial correction for bone pathology was observed in all GT-treated groups. Overall, oral tolerance induction using immunodominant peptides promises to significantly enhance the efficacy of AAV-GT for MPS IVA.
Access all drug discovery papers and probability of success in trials forecasts:
Access all drug discovery papers and probability of success in trials forecasts:
Drug Discovery Landscape
1 orphan drug designation for Mucopolysaccharidosis type 4.
1 orphan drug designation for Mucopolysaccharidosis type 4.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase | proteins | FDA | 2008-09-10 | — | Vivendy Therapeutics LTD |
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