Nationwide survey of neonatal mass-screening for congenital adrenal hyperplasia in Japan

Abstract Introduction: Neonatal mass-screening for 21-hydroxylase deficiency (21-OHD) congenital adrenal hyperplasia (CAH) conducted in 51 laboratories throughout Japan was surveyed, and the screening data on a total of 4 085 448 neonates screened by March 1992 were collected. Methods: 17-OHP in disc blood was measured by ELISA. Specimens were initially assayed without ether extraction (direct assay). The combination of a percentile and concentration level was used for cut-off (the first cut-off ) in assessing the 17-OHP value measured by direct assay by 47 laboratories. In 43 laboratories, samples with values higher than the cut-off level were extracted in ether and 17-OHP measured again. Infants with 17-OHP values in the ether extract higher than the second cut-off level were either referred to a hospital or contacted for a second specimen. Results: A total of 217 patients with 21-OHD were detected. The incidence of the disease detected by newborn mass-screening was 1 18 827 live births (95% confidence interval 1 12 265–1/29 626), which was more than double the incidence by case survey ( 1 43 764). Derived heterozygote incidence and gene frequency were 1 69 ( 1 56 – sol1 87 ) and 0.007 (0.006–0.009), respectively. The ratio of male to female was 1.13, which was significantly higher than that by case survey (0.60). The ratio of salt-wasting to simple virilizing form was 4.3, which was significantly higher than that reported from other countries or from case survey in Japan (1.2). The incidences from newborn screening in Shikoku Islands ( 1 6785 ) and its adjacent Chyugoku Area ( 1 10 804) were significantly higher ( P Discussion: These results suggest that about half of the patients with CAH in Japan were missed prior to newborn screening and that most of them were male and/or had severe salt-wasting disease. It is concluded that nationwide neonatal screening in Japan is a important procedure for early detection of 21-OHD CAH.