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GTR Home > Conditions/Phenotypes > Hypophosphatasia

Summary

Excerpted from the GeneReview: Hypophosphatasia
Hypophosphatasia is characterized by defective mineralization of growing or remodeling bone, with or without root-intact tooth loss, in the presence of low activity of serum and bone alkaline phosphatase. Clinical features range from stillbirth without mineralized bone at the severe end to pathologic fractures of the lower extremities in later adulthood at the mild end. While the disease spectrum is a continuum, seven clinical forms of hypophosphatasia are usually recognized based on age at diagnosis and severity of features: Perinatal (severe): Characterized by pulmonary insufficiency and hypercalcemia Perinatal (benign): Prenatal skeletal manifestations that slowly resolve into one of the milder forms Infantile: Onset between birth and age six months of clinical features of rickets without elevated serum alkaline phosphatase activity Severe childhood (juvenile): Variable presenting features progressing to rickets Mild childhood: Low bone mineral density for age, increased risk of fracture, and premature loss of primary teeth with intact roots Adult: Characterized by stress fractures and pseudofractures of the lower extremities in middle age, sometimes associated with early loss of adult dentition Odontohypophosphatasia: Characterized by premature exfoliation of primary teeth and/or severe dental caries without skeletal manifestations

Genes See tests for all associated and related genes

  • Also known as: AP-TNAP, APTNAP, HOPS, HPPA, HPPC, HPPI, HPPO, TNALP, TNAP, TNS-ALP, TNSALP, ALPL
    Summary: alkaline phosphatase, biomineralization associated

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