[A clinical study on virilization of external genitalia in congenital adrenal hyperplasia]

In the newborn female with congenital adrenal hyperplasia (CAH), there are variable degrees of clitoral enlargement and virilization of the urethra. In order to investigate the factors that cause these variations, the degree of musculinization of the external genitalia in 44 patients with CAH was studied retrospectively.

This study includes a total of 44 patients with CAH aged 2 months to 12 years and 11 months old who had consulted Nagoya City University Hospital from 1977 to 1994. The length of clitoris on the first consultation was compared with the age and its change was followed. Also, the relationship among the length of clitoris on the first consultation, the degree of urethral virilization, the clinical forms i.e. salt-losing or simple-virilization, and the glucocorticoid hormonal condition were investigated with each other. In 5 pairs of sisters, the length of clitoris on the first consultation was compared within each pairs, and also the degree of urethral virilization was compared.

The clitoral length on the first consultation was significantly correlated with the age (y = 1.8 x + 1.8, r = 0.7, p < 0.0001). The mean clitoral length at birth calculated from these data was 18 mm, which is as large as that of adult female one, and the clitoral enlargement rate was 1.8 mm/yr. The correlation was not clear between the clitoral length and the degree of urethral virilization, the clinical forms, and the glucocorticoid hormonal condition, either. On the other hand, the degree of urethral virilization was comparable within clitoral length was not comparable within them.

The urethral virilization was suggested to be determined by the internal hormonal environment during embryonal stage which was shared by the each pair of sisters. On the Other hand, the clitoral length was depend on the patient's age though the factor which determined the length was not apparent. These facts indicated that, not only the severely musculinizing cases, but also the new born female with mildly virilizing urethra should be followed strictly not to undergo the clitoral enlargement.