Effects of adrenal steroids on the bone metabolism of children with congenital adrenal hyperplasia.

The primary treatment for patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) is glucocorticoid replacement therapy, which at supraphysiologic levels can result in diminished bone accrual and lead to osteopenia and osteoporosis. Unlike other diseases treated with chronic glucocorticoid therapy, previous studies of patients with 21OHD have not demonstrated a detrimental effect of glucocorticoid treatment on bone mineral density (BMD). It has been postulated that the elevated androgens typically found in these patients have a protective effect on bone integrity, but the precise mechanism remains unknown. We propose that the inhibitory effect of corticosteroid therapy on bone formation is counteracted by estrogen's effect on bone resorption through the RANK-L/osteoprotegerin (OPG) system. A better understanding of the mechanism by which patients with 21OHD are protected against bone loss may lead to novel therapeutic measures to prevent or treat osteopenia and osteoporosis in other conditions, including postmenopausal women.