I CELL DISEASE

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; I Cell Syndrome; Inclusion Cell Syndrome; Inclusion Cell Disease

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.

Diagnostic testing:

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  Genetic tests for mutations in the IDUA gene;

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  Testing for the GNPTAB gene;

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  Testing for the GNPTA gene that leads to a deficiency in the enzyme UDP-N- acetylglucosamine 1 phosphotransferase; and

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  Elevated serum levels of lysosomal enzymes.

Physical findings:

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  Psychomotor deterioration;

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  Short stature;

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  Characteristic coarse facial features with bulging eyes, low nasal bridge, and overgrown gums (gingival hyperplasia);

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  Corneal clouding;

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  Organomegaly (enlarged organs);

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  Growth failure;

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  Thickened skin with distinct facial features;

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  Generalized hypotonia (low muscle tone);

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  Contractures in all large joints;

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  Thoracic chest wall deformity;

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  Kyphosis (excessive outward curve of spine);

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  Clubbed feet;

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  Deformed long bones;

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  Dislocation of the hips;

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  Thickening and insufficiency of the mitral and aortic valves; and

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  Progressive mucosal thickening narrows the airways and stiffening of the thoracic cage resulting in respiratory insufficiency.

ICD-9: 272.7

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.

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:

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

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

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  Evidence of neurodevelopmental delay.

Suggested Listings for Evaluation:

REMARKS