Sanfilippo Syndrome (MPS III)
Description
Sanfilippo Syndrome, also known as Mucopolysaccharidosis Type III (MPS III), is a rare genetic disorder that affects the body‘s ability to break down complex sugars called glycosaminoglycans (GAGs). This buildup of GAGs primarily affects the brain and central nervous system, leading to a range of developmental delays, cognitive decline, and physical challenges. While there is currently no cure for Sanfilippo Syndrome, early diagnosis and management can help improve quality of life for individuals and their families.
Genes Involved
Sanfilippo Syndrome is caused by mutations in one of four genes involved in the breakdown of heparan sulfate, a type of GAG. These genes are:
- SGSH (MPS IIIA): The most common type of Sanfilippo Syndrome.
- NAGLU (MPS IIIB): Causes a less severe form of the disorder.
- HGSNAT (MPS IIIC): Often presents with a more severe course.
- GNS (MPS IIID): The rarest type of Sanfilippo Syndrome.
Recognizing the Signs and Symptoms
The signs and symptoms of Sanfilippo Syndrome typically appear in early childhood, often between the ages of 2 and 6 years. Early signs may be subtle, but as the condition progresses, the following may become noticeable:
- Developmental delays: Speech and language development may be slower than expected. Learning difficulties and intellectual disabilities may also occur.
- Behavioral issues: Children with Sanfilippo Syndrome may exhibit hyperactivity, aggression, and attention deficit issues.
- Physical features: Characteristic facial features may develop, including a coarse face with a prominent forehead, large ears, and a flattened nose bridge.
- Skeletal abnormalities: Joint stiffness, limited range of motion, and skeletal deformities can occur.
- Respiratory problems: Recurrent ear infections, enlarged tonsils, and sleep apnea are common.
- Other issues: Hernias, vision problems, and seizures may also occur.
Causes
Sanfilippo Syndrome is an inherited disorder, meaning it is passed down from parents to their children. Both parents must carry the mutated gene for their child to inherit the condition. In most cases, the mutation occurs spontaneously, meaning neither parent has the condition but carries the gene.
Inheritance/recurrence risk
Sanfilippo Syndrome is typically inherited in an autosomal recessive pattern. This means that an individual must inherit two copies of the mutated gene, one from each parent, to develop the disorder. If both parents carry the mutated gene, there is a 25% chance their child will inherit the condition. There is also a 50% chance their child will be a carrier of the mutated gene but not develop the condition, and a 25% chance their child will inherit two normal copies of the gene and be unaffected.
