[Neonatal screening of congenital adrenal hyperplasia due to 21-hydroxylase deficiency: Lille experience 1980-1996]

The results of the neonatal screening of congenital adrenal hyperplasia due to 21-hydroxylase deficiency by 17-hydroxyprogesterone measurement from blood spot on blotting-paper in 408,138 newborns in the French Nord-Pas-de-Calais region from 1980 to 1996 are reported.

This measurement successively used a tracer tritium labelled (RIA H3), 125 iodine (RIA I125), then immunofluorometric method (Delfia). From 1992, sampling was systematically performed at the third day of life.

Thirty-three cases were detected and confirmed (20 boys and 13 girls). Diagnosis was made before recalling on a clinical basis in three boys and eight girls. In 22 cases (17 boys and five girls) when diagnosis was not made before recalling, it could have been suspected in three girls because of a sex ambiguity once associated with dehydration and in eight boys because of failure to thrive (six times) or a marked dehydration (twice). Lack of sex ambiguity in two girls characterized non classical form of the illness. These two patients benefited from the early detection of the illness on growth data. Out of 49 subjects who died before recall, three could be suspected of bearing 21-hydroxylase deficiency. One single false negative case was found, which led to decrease cut-off value. On the other hand, false positive cases were frequent (0.37%), mainly in premature newborns (88% of cases).

Although decrease of median age for recall at 7 days did not prevent the occurrence of two cases of dehydration, neonatal screening of 21-hydroxylase deficiency appears to be efficient, as far as diagnostic strategy is considered.