Hypophosphatasia is a rare inborn error of metabolism characterized by defective bone and teeth mineralization due to deficiency of tissue-nonspecific isoenzyme of alkaline phosphatase activity. Intrauterine bone mineralization is markedly reduced in affected fetuses. Herein, we present a perinatal lethal form of hypophosphatasia associated with skelatal deformity and hypercalcemia whose prenatal diagnosis could not be made and to discuss this rare disorder in a newborn with skelatal deformity. This case illustrates the importance of prenatal care, diagnosis of the index case and the need for more careful prenatal evaluation of subsequent pregnancies.

Keywords: hypophosphatasia, perinatal lethal, alkaline phosphatase