RESUMEN
Research of the frequency of 21-OH enzyme deficiency, autosomal recessive disease, caused by aberrations in the short arm of chromosome 6 was performed in order to prevent CAH (Congenital Adrenal Hyperplasia) manifested by: 1) possible cerebral damage 2) errors of sex attribution 3) behavioral hyperandrogenism 4) metabolic damage. Radioimmunoassay was used where there is competition between a radioactive and a non-radioactive antigens for a fixed number of antibody binding sites. In an 18 month period of screening 6,000 newborns we found one positive case of CAH which we confirmed by dosaging steroids such as, 4-androstenedione, testosterone, ACTH, PRA and electrolytic activity on the serum. We ascertained that an incidence of 1:6,000 in a 18 month period is high enough to deserve attention.