Hypophosphatasia

**Semantic type:** Disease or Syndrome

**Definition:** A rare, serious metabolic disorder caused by mutations in the gene encoding tissue non-specific alkaline phosphatase (TNSALP) activity. It is characterized by low activity of TNSALP in the serum. The signs and symptoms vary significantly and include death in utero, failure to thrive, premature loss of deciduous teeth, early loss of the adult dentition, hypercalcemia, osteomalacia, skeletal defects, renal stones, and movement disorders.