SANFILIPPO SYNDROME

ALTERNATE NAMES

Mucopolysaccaridoses III; MPS III; Sanfilippo Type III;

Oligophrenic Polydystrophy; Polydystrophic Oligophrenia

DESCRIPTION

Sanfilippo syndrome is a type of Mucopolysaccaridoses III (MPS III), a lysomal storage disease, which is caused by the absence or malfunctioning of certain enzymes needed to break down molecules called glycosaminoglycans (mucopolysaccharidoes) – long chains of sugar carbohydrates in each of our cells that help build bone, cartilage, tendons, corneas, skin, connective tissue and joints. Individuals with MPS III either do not produce enough of one of the enzymes or they produce enzymes that do not work properly. Over time, these sugar chains collect in the cells, blood and connective tissues resulting in permanent, progressive cellular damage that affects the individual’s appearance, physical abilities, organ and system functioning, and, in most cases mental development. There are four main types of Sanfilippo syndrome:

• Sanfilippo A, the most severe of the MPS III disorders, is caused by the missing or altered enzyme heparan N-sulfatase. Children with this disease have the shortest survival rate among those with the MPS III disorders.

• Sanfilippo B is caused by the missing or deficient enzyme alpha-N-acetylglucosaminidase.

• Sanfilippo C results from the missing or altered enzyme acetyl-CoAlpha-glucosaminide acetyltransferase.

• Sanfilippo D is caused by the missing or deficient enzyme N-acetylglucosamine 6-sulfatase.

The symptoms of Sanfilippo syndrome include: neurological damage, intellectual disability or developmental delay, behavioral problems, hearing loss, corneal degeneration, coarse or rough facial features, short stature, dysplasia, thickened skin, enlarged liver or spleen, hernias, excessive body hair growth, claw-like hands, joint stiffness, carpal tunnel syndrome, respiratory infections, sleep apnea and heart disease. The disorder is seen in about 1 in 70,000 births. Unlike other forms of MPS III, symptoms appear after the first year of life. A decline in learning ability typically occurs between ages 2 and 6. The child may have normal growth during the first few years, but final height is below average. Delayed development is followed by deteriorating mental status.

DIAGNOSTIC

TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING

Blood culture, echocardiogram, slit lamp eye exam, skin fibroblast culture, and x-rays of the bones. Diagnosis can be made through clinical examination and urine tests. Enzyme assays are also used. Prenatal diagnosis using amniocentesis and chorionic villus sampling can verify if a fetus either carries a copy of the defective gene or is affected with the disorder.

ICD-9: 277.5 Mucopolysaccharidosis

ONSET AND PROGRESSION

The syndrome causes significant neurological symptoms, including severe intellectual disability. IQs may be below 50. Most persons with Sanfilippo syndrome live into their teenage years. Some individuals live longer, while others with severe forms die at an earlier age. Symptoms appear most severe in persons with Sanfilippo A syndrome.

TREATMENT

Currently there is no known treatment. Medical care is directed at treating systemic conditions and improving the person's quality of life. Physical therapy and daily exercise may delay joint problems and improve the ability to move. 

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation: Clinical examination that describes diagnostic features of the impairment and laboratory studies are needed to confirm the diagnosis. Laboratory tests showing results of genetic testing, enzyme study tests, urine tests, and MRI or CT scan.

Suggested Listings for Evaluation:

DETERMINATION

LISTING

REMARKS

Meets Listing

Medical Equals

110.08 B

Evaluate most severe forms with early childhood onset under 110.08 B; for less severe, late onset forms, evaluate under the affected body systems.