Sanfilippo syndrome

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Sanfilippo syndrome
Synonyms	Mucopolysaccharidosis type III (MPS III)
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Specialty	Medical genetics
Symptoms	Developmental delay, behavioral problems, sleep disturbances, hearing loss, vision problems
Complications	N/A
Onset	Early childhood
Duration	Progressive
Types	Type A, Type B, Type C, Type D
Causes	Genetic mutation
Risks	Autosomal recessive inheritance
Diagnosis	Genetic testing, urine test for glycosaminoglycans
Differential diagnosis	Other mucopolysaccharidoses, autism spectrum disorder
Prevention	N/A
Treatment	Supportive care, enzyme replacement therapy (experimental)
Medication	N/A
Prognosis	Poor, with progressive neurological decline
Frequency	1 in 70,000 births
Deaths	Varies, often in teenage years or early adulthood

Sanfilippo syndrome, also known as Mucopolysaccharidosis type III (MPS III), is a genetic disorder that primarily affects the central nervous system. It is one of the mucopolysaccharidoses, a group of lysosomal storage disorders caused by the body's inability to break down glycosaminoglycans (GAGs), specifically heparan sulfate.

Etiology

Sanfilippo syndrome is caused by mutations in one of four genes, each responsible for producing an enzyme involved in the degradation of heparan sulfate. These genes are:

• SGSH (Sanfilippo syndrome type A)
• NAGLU (Sanfilippo syndrome type B)
• HGSNAT (Sanfilippo syndrome type C)
• GNS (Sanfilippo syndrome type D)

The mutations lead to a deficiency in the corresponding enzyme, resulting in the accumulation of heparan sulfate in the lysosomes of cells, particularly affecting the brain and nervous system.

Clinical Presentation

Symptoms of Sanfilippo syndrome typically appear in early childhood and may include:

• Developmental delay
• Behavioral problems
• Sleep disturbances
• Progressive intellectual disability
• Seizures
• Hearing loss
• Vision problems

As the disease progresses, children may lose the ability to speak, walk, and perform other basic functions.

Diagnosis

Diagnosis of Sanfilippo syndrome is based on clinical evaluation, family history, and genetic testing. Enzyme assays can be performed to measure the activity of the deficient enzyme in blood or skin cells. Genetic testing can confirm the specific mutation responsible for the disorder.

Management

There is currently no cure for Sanfilippo syndrome. Management focuses on supportive care to improve quality of life and may include:

• Physical therapy
• Occupational therapy
• Speech therapy
• Behavioral therapy
• Seizure management

Research is ongoing into potential treatments, including enzyme replacement therapy, gene therapy, and substrate reduction therapy.

Prognosis

Sanfilippo syndrome is a progressive disorder with a variable prognosis. Most individuals with the condition experience a decline in cognitive and motor skills, with life expectancy often reduced to the second or third decade of life.

Epidemiology

Sanfilippo syndrome is a rare disorder, with an estimated incidence of 1 in 70,000 births. It affects both males and females equally and occurs in all ethnic groups.

See also

• Lysosomal storage disease
• Mucopolysaccharidosis
• Genetic disorder