What is Sanfilippo Syndrome?
What is Sanfilippo Syndrome?Sanfilippo Syndrome, or mucopolysaccharidosis type III or MPS III, is a rare genetic disorder. The disease often manifests early in life and affects the central nervous system (the brain and spinal cord). Sanfilippo Syndrome causes systemic symptoms and neurodegeneration, including early-onset dementia.
Types of Sanfilippo Syndrome
TypesThere are four subtypes of Sanfilippo Syndrome, which are:
- MPS IIIA. The most common form of the disease usually causes symptom onset earlier in life and a short life expectancy (most patients do not live beyond the teenage years). Mutations of the SGSH gene cause IIIA.
- MPS IIIB. Caused by mutations in the NAGLU gene, patients with this form of the disease have a slightly longer life expectancy than those with type IIIA.
- MPS IIIC. Patients with this form of Sanfilippo Syndrome, caused by mutations in the HGSNAT gene, may rarely live to early adulthood.
- MPS IIID. The rarest form of the disease, this subtype, is caused by mutations in the GNS gene.
Stages of Sanfilippo Syndrome
StagesThere are three stages of Sanfilippo Syndrome:
- Stage I: Occurs between the ages of three and six years. Early motor skill development is delayed. Speaking skills may never manifest or are lost. Diagnosis can be difficult at this stage because children may not have signs of the condition.
- Stage II: This stage usually comes about between the ages of five and ten, and is marked by irregular sleep, dementia, and aggressive or hyperactive behavior.
- Stage III: After age 10, children with Sanfilippo Syndrome can have balance issues and stunted growth. Most children will be nonverbal at this stage.
Signs & Symptoms of Sanfilippo Syndrome
SymptomsSymptoms of Sanfilippo Syndrome vary widely depending on the disease’s subtype and the affected child’s age. Most symptoms develop in early childhood.
Symptoms can include:
- Behavioral problems
- Delayed or regressed speech
- Trouble sleeping
- Developmental regression
- Seizures
- Coarse facial features
- Movement disorders
- Difficulty communicating
Symptoms occurring at later stages of the disease include:
- Hearing loss
- Visual impairment
- Arthritis
- Respiratory issues
What Causes Sanfilippo Syndrome?
CausesSanfilippo Syndrome is a genetic disorder. It is passed on in an autosomal recessive pattern, meaning a child must receive one defective gene responsible for the disease from each parent to be affected. These defective genes result in a shortage of enzymes to break down certain sugar molecules. These molecules then build up in the body and cause health problems.
Risk Factors
Risk FactorsSince Sanfilippo Syndrome is an inherited disorder, a family history of the disease increases the risk that you will pass it on to a child. However, many families have not identified a history of the disorder. Male and female children are affected equally since the disease is not linked to the sex chromosome.
Prevention
PreventionUnfortunately, there is no way to prevent Sanfilippo Syndrome if a child has inherited the defective genes responsible. Genetic testing prior to becoming pregnant can help you understand your risk of passing on Sanfilippo Syndrome and other genetic disorders.
Trust NewYork-Presbyterian for Sanfilippo Syndrome Care
NewYork-Presbyterian has a world-renowned pediatric team that can help guide you and your child through a care plan for Sanfilippo Syndrome. Our Division of Genetics also sees couples for preconception genetic testing (carrier screening). Our physicians understand the importance of prompt diagnosis and individualized treatment in giving your child the best quality of life and prognosis possible.