Genotype Is Associated to the Degree of Virilization in Patients With Classic Congenital Adrenal Hyperplasia.

Molecular defects of consistently decrease 21-hydroxylase activity and result in a variable expression of disease severity in patients with congenital adrenal hyperplasia (CAH). The genotype and biochemical findings were examined in an attempt to reveal any association to the degree of virilization in classic CAH patients. The study included 18 CAH patients with complete characterization of mutations and were sorted based on the severity of the inherited mutations and the expected percentage of 21-hydroxylase enzyme activity. Eleven out of the 18 patients manifested the SW form with the remaining seven exhibiting the SV form. The most frequent genetic defect in the classic salt-wasting (SW) and simple virilising (SV) forms was the IVS2-13A/C>G (36.1%) mutation, followed by delEX1-3 (19.4%) and p.Ile172Asn (19.4%). Four patients, who shared a combination of two mutations belonging to the most severe type, manifested only the SW form. Four out of five patients who shared homozygosity in the IVS2-13A/C>G mutation, demonstrated the SW form and only one demonstrated the SV form. All four patients who shared the p.Ile172Asn mutation, either in the homozygous or compound heterozygous state, manifested the SV form. Interestingly, a female neonate with SW, bearing the IVS2-13A/C>G/Large del, exhibited complete male virilisation (Prader 5). The remaining four affected female new-borns also exhibited the SW form, with two of them virilised as Prader 3 and the other two as Prader 4. Virilisation with clitoromegaly was also observed in one female, who presented premature adrenarche and carried the least severe p.Pro30Leu mutation. The frequency of the underlying mutations in our patients, with the classic form of CAH, varies but were quite similar to the ones reported in the Mediterranean region. Therefore, the identification of severe defects in Cypriot patients and their comparison with the incidence and severity in different populations, will create a valuable diagnostic tool for genetic counseling in the classic form of CAH.