Nonclassic congenital adrenal hyperplasia due to 21-hydroxylase deficiency: clinical presentation, diagnosis, treatment, and outcome

Nonclassic congenital adrenal hyperplasia (NCAH) is one of the most frequent autosomal recessive disorders in man with a prevalence ranging from 0.1 % in Caucasians up to a few percent in certain ethnic groups. Most cases are never diagnosed due to very mild symptoms, misdiagnosing as polycystic ovary syndrome, or ignorance. In contrast to classic CAH, patients with NCAH present with mild partial cortisol insufficiency and hyperandrogenism and will survive without any treatment. Undiagnosed NCAH may result in infertility, miscarriages, oligomenorrhea, hirsutism, acne, premature pubarche, testicular adrenal rest tumors, adrenal tumors, and voice problems among other symptoms. A baseline measurement of 17-hydroxyprogesterone can be used for diagnosis, but the ACTH stimulation test with measurement of 17-hydroxyprogesterone is regarded as the golden standard. The diagnosis can be verified by CYP21A2 mutation analysis. Treatment is symptomatic and usually with glucocorticoids alone. The lowest possible glucocorticoid dose should be used. Long-term treatment with glucocorticoids will improve the symptoms but will also result in iatrogenic cortisol insufficiency and may also lead to long-term complications such as obesity, insulin resistance, hypertension, osteoporosis, and fractures. Although the complications seen in NCAH patients have been assumed to be related to the glucocorticoid treatment, some may, in fact, be associated with prolonged hyperandrogenism. Different risk factors and negative consequences should be monitored regularly in an attempt to improve the clinical outcome. More research is needed in this relatively common disorder.