Molecular genetics and pathophysiology of 17 beta-hydroxysteroid dehydrogenase 3 deficiency.

Autosomal recessive mutations in the 17 beta-hydroxysteroid dehydrogenase 3 gene impair the formation of testosterone in the fetal testis and give rise to genetic males with female external genitalia. Such individuals are usually raised as females, but virilize at the time of expected puberty as the result of increases in serum testosterone. Here we describe mutations in 12 additional subjects/families with this disorder. The 14 mutations characterized to date include 10 missense mutations, 3 splice junction abnormalities, and 1 small deletion that results in a frame shift. Three of these mutations have occurred in more than 1 family. Complementary DNAs incorporating 9 of the 10 missense mutations have been constructed and expressed in reporter cells; 8 of the 9 missense mutations cause almost complete loss of enzymatic activity. In 2 subjects with loss of function, missense mutations testosterone levels in testicular venous blood were very low. Considered together, these findings strongly suggest that the common mechanism for testosterone formation in postpubertal subjects with this disorder is the conversion of circulating androstenedione to testosterone by one or more of the unaffected 17 beta-hydroxysteroid dehydrogenase isoenzymes.

Long-term endocrine sequelae after treatment of medulloblastoma: prospective study of growth and thyroid function.

Endocrine evaluations were performed prospectively in 22 patients with medulloblastoma (ages 2 1/2 to 23 1/2 years at diagnosis), after craniospinal radiation with or without adjuvant chemotherapy. The mean craniospinal hypothalamic-pituitary). and thyroid radiation doses were 3600 and 2400 rads, respectively. Fourteen (73%) of 19 patients who had not yet completed their growth experienced a decrease in growth velocity. However, only three of 10 of these children, who underwent growth hormone stimulation tests, had evidence of deficient growth hormone responses, suggesting that growth hormone secretory or regulatory dysfunction, rather than absolute growth hormone deficiency, is present in the majority of these children. Elevated thyroid-stimulating hormone levels were noted in 15 of 22 patients; one patient had hypothalamic hypothyroidism. Thus, the late effects of therapy for medulloblastoma include frequent endocrine morbidity involving hypothalamic-pituitary and thyroid dysfunction.

Recovery of adrenal function after treatment of adrenocortical carcinoma with o,p'-DDD.

The adrenolytic agent, 2,2-bis[2-chlorophenyl-4-chlorophenyl] 1,1 dichloroethane (o,p'-DDD), was used over a 20-month period following surgery in a 2 3/12-year-old girl for treatment of adrenocortical carcinoma. The child remained free of disease and was maintained on glucocorticoid and mineralo-corticoid supplements for 7 years. Hormonal evaluation was undertaken at 9 9/12 years of age to determine remaining adrenal steroidogenic capacity. Following discontinuation of both hydrocortisone and 9 alpha-fludrocortisone, she remained stable and asymptomatic. Immediately after discontinuing 9 alpha-fludrocortisone, the adrenal glomerulosa was able to respond to stimulation by the renin-angiotensin system as shown by the ability to achieve renal sodium conservation on a restricted sodium intake (less than 10 mEq/d for 5 d). The response of the adrenal fasciculata to ACTH stimulation showed a slower recovery. Baseline levels of cortisol were in the low normal range, but there was no increase in plasma cortisol or urinary 17-hydroxysteroids following stimulation with ACTH. The responses of cortisol, deoxycorticosterone, and corticosterone to ACTH stimulation gradually improved to achieve normal stimulated levels 18 months after stopping medications. Serum testosterone and delta 4-androstenedione were initially increased for level of puberty, while levels of dehydroepiandrosterone were prepubertal. Testosterone and delta 4-androstenedione did not suppress with dexamethasone (2 mg/d for 2 d; 4 mg/d for 2 d), and dehydroepiandrosterone decreased only slightly. However, administration of norethindrone (Norlutin) (10 mg orally, three times a day for 3 d) resulted in suppression while human chorionic gonadotrophin (hCG; 5000 U i.m. daily for 3 d) produced stimulation of testosterone, delta 4-androstenedione and dehydroepiandrosterone. Thus the androgens were felt be predominantly of ovarian origin. Dehydroepiandrosterone rose to low normal levels by 18 months after discontinuation of hydrocortisone. We thus demonstrate for the first time that both the adrenal glomerulosa and fasciculata have the capacity to recover normal function following treatment with o,p'-DDD. Further, we suggest that early exposure to excess adrenal androgens may result in mild alteration of gonadal function.