Abstract
Females with salt-wasting (SW) 21-hydroxylase deficiency (21OHD) may present with mild external genitalia virilization, despite complete or almost complete enzyme inactivation. We therefore analyzed genotype/phenotype correlation in 13 Japanese female patients with SW 21OHD. Criteria for classification into the SW phenotype included history of a salt-losing crisis with documented hyponatremia, hyperkalemia, and markedly elevated plasma renin activity. Urologists and pediatricians determined the Prader genital stage and classified the location of the vaginal entrance into the common urogenital sinus as low, moderate, or high. CYP21A2 gene, coding for 21-hydroxylase, was analyzed with Southern blotting and direct sequencing. Genotypes were categorized into four mutation groups, based on the degree of enzymatic activity (N, complete enzyme inactivation; groups A, < 2%, B, 3-7%, and C > 30%). Basal androgen levels were available from only six out of thirteen patients, so we could not relate androgen levels with the severity of external genitalia virilization. We compared the degree of external genitalia virilization with genotype. The severity of external genitalia virilization varied from Prader stage 1 to 4. One patient who presented with Prader 1 had a genotype consistent with Group B. In addition, discordance between Prader classification and the location of the vaginal entrance was noted; one patient classified as Prader 4 showed low vaginal entrance, while another patient classified as Prader 3 showed high vaginal entrance. The degree of the impairment of 21-hydroxylase activity does not correlate with the severity of virilization of the external genitalia in female patients with the SW type of 21OHD.
