Overview
Mucolipidosis type III alpha/beta (also called ML III alpha/beta, pseudo-Hurler polydystrophy, or mucolipidosis III) is a rare inherited metabolic disorder that belongs to a group of diseases called lysosomal storage disorders. In this condition, the body cannot properly move certain enzymes into the lysosomes — the parts of cells that act like recycling centers, breaking down waste materials. Without these enzymes in the right place, waste products build up inside cells throughout the body, causing damage over time. Mucolipidosis III alpha/beta is caused by changes (mutations) in the GNPTAB gene, which provides instructions for making part of a protein that helps tag enzymes so they can reach the lysosomes. When this tagging system does not work correctly, the enzymes end up in the wrong place and cannot do their job. The disease usually becomes noticeable in early childhood, often between ages 3 and 5. Common symptoms include stiff and painful joints, especially in the hands and shoulders, a curved spine (scoliosis), short stature, coarsened facial features, and heart valve problems. Some children may have mild learning difficulties. The disease progresses slowly, and most people with ML III alpha/beta survive into adulthood, though they often face increasing physical limitations. There is currently no cure, but treatment focuses on managing symptoms and improving quality of life through physical therapy, pain management, and monitoring of the heart and skeleton.
Key symptoms:
Stiff, painful joints — especially in the hands, shoulders, and hipsShort stature (being shorter than expected for age)Curved spine (scoliosis or kyphosis)Coarsened or slightly unusual facial featuresHeart valve problems, especially thickening of the aortic or mitral valveCarpal tunnel syndrome (numbness or tingling in the hands)Clouding of the cornea (the clear front part of the eye)Mild intellectual disability or learning difficulties in some peopleRestricted range of motion in jointsBone abnormalities visible on X-ray (called dysostosis multiplex)Recurrent ear infections or hearing loss in some casesHernia (bulging near the belly button or groin) in some children
Clinical phenotype terms (36)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Childhood
Begins in childhood, roughly ages 1 to 12
Treatments
No FDA-approved treatments are currently listed for Mucolipidosis type III alpha/beta.
View clinical trials →Clinical Trials
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Mucolipidosis type III alpha/beta.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Which specialists should be part of my child's care team, and how often should we see each one?,What signs of heart valve disease should I watch for at home, and when should I go to the emergency room?,Are there any clinical trials or research studies that my child might be eligible for?,What physical activities are safe, and are there any we should avoid to protect the joints?,What school accommodations or support services would you recommend?,How quickly do you expect the disease to progress, and what changes should we prepare for?,Should other family members be tested to see if they are carriers?
Common questions about Mucolipidosis type III alpha/beta
What is Mucolipidosis type III alpha/beta?
Mucolipidosis type III alpha/beta (also called ML III alpha/beta, pseudo-Hurler polydystrophy, or mucolipidosis III) is a rare inherited metabolic disorder that belongs to a group of diseases called lysosomal storage disorders. In this condition, the body cannot properly move certain enzymes into the lysosomes — the parts of cells that act like recycling centers, breaking down waste materials. Without these enzymes in the right place, waste products build up inside cells throughout the body, causing damage over time. Mucolipidosis III alpha/beta is caused by changes (mutations) in the GNPTAB
How is Mucolipidosis type III alpha/beta inherited?
Mucolipidosis type III alpha/beta follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Mucolipidosis type III alpha/beta typically begin?
Typical onset of Mucolipidosis type III alpha/beta is childhood. Age of onset can vary across affected individuals.
Which specialists treat Mucolipidosis type III alpha/beta?
1 specialists and care centers treating Mucolipidosis type III alpha/beta are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.