HYPOPHOSPHATASIA--PERINATAL (LETHAL) and INFANTILE ONSET TYPES

Alkaline Phosphotase Deficiency; Perinatal Lethal Hypophosphatasia; Hypophosphatasia Perinatal Lethal Form; Perinatal Rathburn Disease; Phosphoethanolaminuria; Hypophosphatasia Lethal Form; Hypophosphatasia Infantile Onset; Rathburn's Disease

Hypophosphatasia is a rare, inherited metabolic disorder that affects the development of bones and teeth. There are several forms of this disorder, with the perinatal (lethal) and infantile onset types being the most severe.

Diagnostic testing: Diagnostic testing consisting of subnormally low activity of tissue non-specific alkaline phosphatase (TNALP) enzyme in serum; bone imaging of the bones shows severe demineralization, especially in the metaphyses (the wider part at the extremity of the shaft of a long bone).

Physical findings:

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  A near absence of skeletal mineralization;

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  Fractures;

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  Skin-covered spurs of the knees and elbow;

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  Large fontanels (space between the bones of the skull);

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  Shortened bones;

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  Chest deformities;

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  Muscle weakness;

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  Hypercalcemia (higher than normal level of calcium in your blood); and

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  Multiple congenital abnormalities, leading to respiratory failure.

ICD-9: 275.3

For perinatal (lethal) onset hypophosphatasia, death occurs either in-utero or within the first months of life. Infantile onset hypophosphatasia presents within the first year of life, and has 50% mortality. The cause of death is usually due to respiratory failure. Perinatal (benign) hypophosphatasia type is characterized by prenatal skeletal manifestations that slowly resolve into the milder childhood and adult onset hypophosphatasia types, which have variable clinical courses.

Currently there is no cure or definitive treatment for this disorder.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation:

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

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  Laboratory testing for identified enzyme changes; or

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  Imaging documenting decreases in bone mineralization.

Suggested Listings for Evaluation:

REMARKS

Evaluate the perinatal (lethal) onset type of hypophospatasia, under listing 110.08 A.