[Hypophosphatasia--biochemical and clinical manifestations, molecular genetic principles]

Hypophosphatasia is a rare hereditary metabolic disorder accompanying deficit of tissue nonspecific serum alkaline phosphatase. The incidence of overt forms is estimated about 1:100000 live births. In the prenatal manifestation the disease may cause severe damage to the foetus with intrauterine death. In children there is a defect of mineralization with rickets signs and the subsequent hypercalcaemia a hypercalciuria may lead to death. In adults the main manifestation is osteomalacia, skeletal deformities and fractures, early arthritis. In severe forms the heredity is autosomal recessive type. In mild forms the heredity may be dominant or recessive. In two case reports we present clinical course of the disease in two adult sisters, where diagnosis of hypophosphatasia was first time confirmed in Slovak population using molecular genetic methods.