Non-classical 21-hydroxylase deficiency: clinical and hormonal discrepancies and intrafamilial phenotypic variability

Background. We report here two families illustrating the intrafamilial phen otypic variety of the non-classical 21-hydroxylase deficiency and other dis crepancies between clinical and hormonal data. Patients, methods and results. The index case in the first family had a mil d hirsutism which appeared peripuberally and basal 17-hydroxiprogesterone o ver the measurement limit. One of her sister, without hair excess, had the same biochemical abnormality. The index case in the second family was detec ted at five years because of early appearance of pubic hair and basal 17-hy droxiprogesterone over the measurement limit. One of her siblings, a 16-yea r old girl, was also diagnosed of mild hirsutism and increased levels of ba sal and post-stimulation 17-hydroxiprogesterone. Conclusions. The association of marked biochemical abnormalities with scarc e or no clinical expression in the first family and the different presentat ion form of both cases in the second family suggest that there is something else than the mutation in the CYP 21B gene in the non-classic deficiency o f 21-hydroxylase.