Disability/Illness Description:

Sanfilippo Syndrome (also known as MPS III) is a rare, progressive, and fatal disease. It  affects 1 in 70,000 children. It is a genetic condition.  Sanfilippo affects the metabolism of complex molecules.  It results in severe damage to the entire body, but most significantly to the brain.

The effects of Sanfilippo start at birth, but don’t become noticeable until 2-6 years old. As the toxins build up because of Sanfilippo, the cellular damage progresses. Relentless and devastating, Sanfilippo has 100% mortality rate, with children typically passing away in their early teens.

Mucopolysaccharidosis type III (MPS III), also known as Sanfilippo syndrome, is a progressive disorder that primarily affects the brain and spinal cord (central nervous system). It is characterized by deterioration of neurological function (neurodegeneration), resulting in many of the features of the condition. Other body systems can also be involved, although the physical features are usually mild in the early stages.

People with MPS III generally do not display any features of the condition at birth, but they begin to show signs and symptoms of the disorder during early childhood. Affected children often initially have delayed speech and behavior problems. They may become restless, destructive, anxious, or aggressive.  Some display features of autism spectrum disorder. Sleep disturbances are also very common in children with MPS III. This condition causes progressive intellectual disability and the loss of previously acquired skills (developmental regression). In later stages of the disorder, people with MPS III may develop seizures and movement disorders.

Resources and Family Support: 

Boston Children’s Lysosomal Storage Disorder (BoLD) Program Boston Children’s Lysosomal Storage Disorder (BoLD) Program is a multidisciplinary, patient centered program for children and adults with known or suspected lysosomal storage disorders.

Ben’s DreamSanfilippo Research Foundation based in Massachusetts. 

Family Support  Programs – National MPS Society

Caring for a Seriously or Chronically Ill Child Coping and advice for parents caring for a child with a serious or long-term illness KidsHealth from Nemours.

Courageous Parents Network – Information and support for families and providers caring for children with serious illness.

Other Information:

JKL Sanfilippo Research Foundation – Information for families. 

Mucopolysaccharidosis type III InformationU.S. National Library of Medicine Medline Plus

Mucopolysaccharidosis type III – Genetic and Rare DIsease Information Center 

What Causes Sanfilippo Syndrome? – Cure Sanfillipo Foundation 

What Is Sanfilippo Syndrome? – Information for parents from KidsHealth

Fact Sheet last updated on: 1/20/2021