Correlation between genotype and hormonal levels in heterozygous mutation carriers and non-carriers of 21-hydroxylase deficiency.

Congenital adrenal hyperplasia, both in its classic (CCAH) and non-classic form (NCAH), is a morbid condition sustained by the absent or reduced function of one of the enzymes involved in cortisol biosynthesis - mainly 21 hydroxylase - associated with different levels of clinical androgenization. In a wide group of relatives of patients affected by CCAH and NCAH (no.=222) and healthy volunteers (no.=30), a clinical, hormonal and genetic evaluation was performed in order to differentiate between the condition of heterozygous mutation carrier and non-carrier of any among 21-hydroxylase gene (CYP21) mutations. This study shows that clinical presentation and basal 17α-hydroxyprogesterone (17α-OHP) are not able to differentiate between heterozygous carriers and non-carriers, whereas 17α-OHP value after ACTH bolus is significantly different between heterozygous carriers and non-carriers: p<0.001 with a cut-off value of 3 ng/ml (90% sensitivity and 74,3% specificity). Moreover, our data indicate that 17α-OHP response to ACTH may be a useful tool to select subjects for genetic analysis.