Congenital adrenal hyperplasia due to 17-alpha-hydroxylase/17,20-lyase deficiency is an autosomal recessive disorder which results in impaired production of cortisone and sex hormones. This results in hypertension and low serum potassium. Untreated, females do not develop breasts and pubic hair, and do not begin to menstruate at puberty. Males have incomplete sexual development at birth and may appear to be female or of uncertain gender. Untreated, affected males develop breast enlargement (gynecomastia) at puberty. Treatment is possible by providing the hormones that the body would normally produce. This rare disorder is more common in Mennonites and in parts of Brazil.