MPS IIIA: A Rare Inherited Neurodegenerative Disorder


Mucopolysaccharidosis type IIIA (MPS IIIA), or Sanfilippo syndrome type A, is a rare inherited neurodegenerative disorder. Children with MPS IIIA do not produce enough enzyme activity to break down a substance in the body called heparan sulfate.

As heparan sulfate accumulates, it affects the normal functions of the body and, in particular, the brain. The lack of enzyme activity is due to a defective gene that would normally instruct the cells of the body to make a functional enzyme. The defective gene is called N-sulfoglucosamine sulfohydrolase (SGSH).

Signs and symptoms usually become apparent in early childhood and include speech problems, development delays, challenging behaviors, extreme hyperactivity and poor sleep.

MPS IIIA has a worldwide incidence of up to 1.62 per 100,000 live births.

The Science Behind Gene Therapy in Development for MPS IIIA

LYS-SAF302, for MPS IIIA is under clinical development by researchers at Lysogene, a Paris-based biotechnology company. Sarepta and Lysogene formed a license agreement for LYS-SAF302.

This program aims to address the underlying cause of MPS IIIA: a genetic mutation that prevents the production of an enzyme that breaks down excess sugar in the body, particularly in the brain cells. The goal is to replace a faulty gene with a potentially functional copy of the gene. By replacing the defective gene, it is hoped that the body will start making sufficient quantities of the critical enzyme and, therefore, slow or halt the progression of the disease. 

Clinical Trials

A clinical trial for LYS-SAF302 is currently underway.

MPS IIIA Resources

Patient Advocacy Groups

The groups below represent a few of the organizations that help connect patients and families to education, research, support services, and the broader MPS IIIA community.


Mucopolysaccharidosis Type IIIA Resources


Additional Resources