GTR Home > Conditions/Phenotypes > Hypophosphatasia

Disease characteristics

Excerpted from the GeneReview: Hypophosphatasia
Hypophosphatasia is characterized by defective mineralization of bone and/or teeth 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. At least six clinical forms are currently recognized based on age at diagnosis and severity of features: Perinatal (lethal) hypophosphatasia characterized by respiratory insufficiency and hypercalcemia. Perinatal (benign) hypophosphatasia with prenatal skeletal manifestations that slowly resolve into the milder childhood or adult form. Infantile hypophosphatasia with onset between birth and age six months of rickets without elevated serum alkaline phosphatase activity. Childhood hypophosphatasia that ranges from low bone mineral density for age with unexplained fractures to rickets. Adult hypophosphatasia characterized by early loss of adult dentition and stress fractures and pseudofractures of the lower extremities in middle age. Odontohypophosphatasia characterized by premature exfoliation of primary teeth and/or severe dental caries as an isolated finding or as part of the above forms of hypophosphatasia.

Associated genes

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Write to the Help Desk