Molecular analysis of CYP21A2 can optimize the follow-up of positive results in newborn screening for congenital adrenal hyperplasia.

Neonatal screening for congenital adrenal hyperplasia (CAH) is useful in diagnosing salt wasting form (SW). However, there are difficulties in interpreting positive results in asymptomatic newborns. The main objective is to analyze genotyping as a confirmatory test in children with neonatal positive results. Patients comprised 23 CAH children and 19 asymptomatic infants with persistently elevated 17-hydroxyprogesterone (17OHP) levels. CYP21A2 gene was sequenced and genotypes were grouped according to the enzymatic activity of the less severe allele: A1 null, A2 < 2%, B 3-7%, C > 20%. Twenty-one children with neonatal symptoms and/or 17OHP levels > 80 ng/ml carried A genotypes, except two virilized girls (17OHP < 50 ng/ml) without CAH genotypes. Patients carrying SW genotypes (A1, A2) and low serum sodium levels presented with neonatal 17OHP > 200 ng/ml. Three asymptomatic boys carried simple virilizing genotypes (A2 and B): in two, the symptoms began at 18 months; another two asymptomatic boys had nonclassical genotypes (C). The remaining 14 patients did not present CAH genotypes, and their 17OHP levels were normalized by 14 months of age. Molecular analysis is useful as a confirmatory test of CAH, mainly in boys. It can predict clinical course, identify false-positives and help distinguish between clinical forms of CAH.

Response of the free alpha-subunit to GnRH distinguishes individuals with 'functional' from those with permanent hypogonadotropic hypogonadism.

The aim of this study was to compare the responses of pituitary gonadotropins and the free alpha-subunit (FAS), measured by sensitive immunofluorometric assays at 0, 30 and 60 min after 100 microg GnRH i.v. in a group of 32 normal prepubertal boys (NB) and a group of 17 adult males with complete hypogonadotropic hypogonadism (HH). At time 0 min, medians of the serum levels of LH, FSH and FAS were not different in both groups. At 30 min (29.81 and 8.56 pmol/l) and 60 min (24.10 and 7.74 pmol/l) as well as peak levels (29.76 and 8.56 pmol/l), 'deltas' (peak minus baseline; 25.89 and 0.34 pmol/l) and 'fold'-increase (peak divided by baseline; 7.0-fold and 1. 6-fold), the medians were significantly higher in NB than in HH, respectively. There were fewer overlapping values of FAS between the 2 groups and they occurred in only 4% of the total number of subjects when 'fold' was considered. The measurement of FAS by a very sensitive immunofluorometric assay, after GnRH, distinguishes responses of NB from those of adult men with HH, that is of functional from permanent HH.