CYP11A1 and Failure to thrive: Severe disruption of this protein causes the classic form of CYP11A1 (P450scc) deficiency, with symptoms including early (neonatal) onset salt wasting crisis (hyponatremia, hyperkaliemia, failure to thrive, hypotension), adrenal crisis (hypoglycemia, failure to thrive, hypotension), activation of the hypothalamo–hypopituitary axis with raised corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) levels (skin and mucous hyperpigmentation), female or undervirilized external genitalia in 46, XY patients, and small adrenal glands on imaging [3,5,6,7,8,9].