Grúpa neamhoird oidhreachta ar na Faireoga ADRENAL, de bharr lochtanna einsíme i sintéis cortisol (HYDROCORTISONE) agus/nó ALDOSTERONE as a dtagann carnadh réamhtheachtaithe do ANDROGENS. Ag brath ar an éagothroime hormóin, is féidir hipearpláis adrenal ó bhroinn a aicmiú mar chur amú salainn, hipirtheannas, virilizing, nó feminizing. Is é an locht is coitianta i STEROID 21-HYDROXYLASE. Tarlaíonn lochtanna eile i STEROID 11-BETA-HYDROXYLASE; Steroid 17-ALPHA-HYDROXYLASE; nó 3-béite-hydroxysteroid dehydrogenase (3-HYDROXYSTEROID DEHYDROGENASES).