Conversion from pure 17,20-desmolase- to combined 17,20-desmolase/17 alpha-hydroxylase deficiency with age.

A previously described phenotypically female 46,XY-individual with 17,20-desmolase deficiency was followed from adolescence to adulthood. While at age 16.9 years her 17 alpha-hydroxylating capacity was normal and steroids not hydroxylated in position 17 low, decreasing 17 alpha-hydroxylated and increasing unhydroxylated steroids were observed thereafter up to the age of 25.2 years. Simultaneously with the steroid changes, previously normal blood pressure (110/80 mmHg) increased (180/130 mmHg). Since 17 alpha-hydroxylation and 17,20-desmolase activity are regulated by one cytochrome P450-17 alpha, it is concluded that, in this same patient, 17 alpha-hydroxylase activity was normal during childhood and adolescence, but decreased in the young adult. 17,20-desmolase activity, by contrast, was completely absent already in the fetus, causing absence of masculinization. The factors modulating this difference in cytochrome P450-17 alpha activity with age are as yet unknown.