Hypophosphatasia is an inherited metabolic disease of the bones which causes reduced activity of the tissue-non-specific alkaline phosphatase (TNSALP) as the result of a mutation of the TNSALP gene. The disease is rare, and its main characteristics are poor mineralization of the bones and teeth, lower activity of alkaline phosphatase in the serum, a very varied clinical picture and prognosis in a range from intrauterine death to early loss of teeth, as the only sign of the disease. Hypophosphatasia is divided into seven clinical forms: perinatal lethal, infantile semi-lethal, mild childhood and adult are the four main types. Alongside these there are also perinatal non-lethal, odontohypophosphatasia and the rarest type – pseudohypophosphatasia. Pseudohypophosphatasia is defined as a form identical to infantile hypophosphatasia but with normal alkaline phosphatase in the serum. In this study, the clinical picture in all forms of hypophosphatasia is described, with a detailed presentation of radiological findings and biochemical and other tests on which diagnosis is based. Better understanding of hypophosphatasia could contribute to earlier and more frequent diagnosis of this disease.

Keywords: HYPOPHOSPHATASIA – genetics, diagnosis, radiography; BONE DISEASES, METABOLIC – genetics, diagnosis, radiography;
ALKALINE PHOSPHATASE – blood, genetics
Category: Review
Volume: Vol. 51, No 2, april - june 2007
Authors: I. Ligutić, I. Barišić, J. Vrdoljak, D. Antičević
Reference work: