35 PERINATAL LETHAL FORM OF HYPOPHOSPHATASIA Hypophosphatasia is a rare and lethal metabolic bone disease characterised by low or absent serum and tissue-alkaline phosphatase activities resulting in insufficient bone mineralisation. Hypophosphatasia has been reported throughout the world and affects all races; however, it is especially prevalent in Manitoba, Canada, where about one in 25 individuals is a carrier and 1: 2.500 newborns manifest severe disease. Six forms of hypophosphatasia have been identified. The perinatal (lethal), infantile, childhood and adult types are distinguished from one another by the age at which clinical manifestations and bone lesions are recognised. Patients with dental manifestations but no skeletal disease are considered to have odontohypophosphatasia. Pseudohypophosphatasia is a rare variant of hypophosphatasia characterised by normal serum alkalinephosphatase (ALP) activity (1). The severe infantile form of hypophosphatasia is autosomal-recessively inherited and is lethal in the neonatal period (2). We report a neonate with congenital hypophosphatasia in which prenatal diagnosis could not be carried out, in spite of the termination of the mother’s former pregnancy because of abnormal skeletal development. 35 Beg m Atasay, Ayla G nlemez, Sevim nal K z late , Merih Berbero lu, Saadet Arslan Begüm Atasay, Ayla Günlemez, Sevim Ünal Kızılateş, Merih Berberoğlu, Saadet Arsan 35 Y.Ad, Y. Ad PERINATAL LETHAL FORM OF HYPOPHOSPHATASIA ––––––––––––––––––––––––– * Department of Pediatrics, Ankara University, Ankara, Turkey –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Received: Feb. 23, 2001 Accepted: May 01, 2001 JOURNAL OF ANKARA MEDICAL SCHOOL V ol 55, No 1, 2002 35-38 SUMMARY Hypophosphatasia is a rare bone disorder characterised by low or absent levels of the serum and tissue non-specific alkaline phosphatase necessary for normal bone mineralisation. The severe infantile form of the disease is autosomal-recessively inherited and is usually lethal in the neonatal period. We report a neonate with congenital hypophosphatasia in which prenatal diagnosis could not be carried out, in spite of the termination of the mother s former pregnancy due to abnormal skeletal development. This report indicates the importance of the index case and the need for more careful prenatal evaluation of subsequent pregnancies. Key Words: Hypophosphatasia, Neonate. ÖZET Perinatal Letal Hipofosfatazya Hipofosfatazya, normal kemik mineralizasyonu i in gerekli olan serum ve doku alkalen fosfataz enzim aktivitesinin azalmas veya olmamas ile karekterli nadir bir kemik hastal d r. Yenido an d neminde l mle sonu lanan hastal n a r infantil formunda kal t m otozomal resesiftir. Burada bir nceki gebeli i iskelet anomalisi nedeniyle sonland r lm ancak sonraki gebelikte prenatal tan yap lmam bir konjenital hipofosfatazya olgusu, prenatal tan n n vurgulanmas amac ile sunulmaktad r. Anahtar Kelimeler: Hipofosfatazya, Yenido an