I CELL DISEASE

ALTERNATE NAMES

Mucolipidosis Type II; MLType II; Inclusion Cell disease; Mucolipidosis II Alpha/Beta; ML II; Mucolipidosis 2; ML 2; GNPTA; Leroy Disease; N-acetylglucosamine 1 phosphotransferase deficiency; ML disorder type 2

DESCRIPTION

I Cell Disease is a rare genetic disorder in which the body lacks a critical metabolic enzyme to break down long chains of sugar molecules. The characteristic findings of I cell disease include psychomotor deterioration, short stature, multiple musculoskeletal abnormalities, characteristic coarse facial features with bulging eyes, low nasal bridge and overgrown gums (gingival hyperplasia), corneal clouding, and organomegaly.

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

Diagnostic testing: Genetic tests for mutations in the IDUA gene, testing for the GNPTAB gene, GNPTA gene that leads to a deficiency in the enzyme UDP-N- acetylglucosamine 1 phosphotransferase, and elevated serum levels of lysosomal enzymes.

Physical findings: Growth failure; thickened skin with distinct facial features; generalized hypotonia. Musculoskeletal abnormalities include contractures in all large joints, thoracic chest wall deformity, kyphosis, clubfeet, deformed long bones, and dislocation of the hips. Cardiac involvement is seen with thickening and insufficiency of the mitral and aortic valves. Progressive mucosal thickening narrows the airways and stiffening of the thoracic cage resulting in respiratory insufficiency.

ICD-9: 272.7

ONSET AND PROGRESSION

Developmental delay and growth failure are the first signs of I Cell Disease, and present in the first year of life. As the child develops, difficulties with motor coordination are evident and manifests with rapid and progressive deterioration. Heart disease and complications of pneumonia are the major causes of death.

TREATMENT

There is no current cure for I Cell Disease. Treatment is supportive. Bone marrow transplantation may be used to delay or correct neurological deterioration. Intravenous treatment with pamidronate may prevent break down of bone tissue, decrease bone pain, and increase mobility.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for evaluation:

• Clinical history and examination that describes diagnostic features of the impairment

• Laboratory tests showing results of genetic testing for mutations in the IDUA gene

• Evidence of neurodevelopmental delay

Suggested Listings for Evaluation:

DETERMINATION

LISTING

REMARKS

Meets Listing

110.08 B

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