Hypophosphatasia

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.