To more fully characterise the P450scc autoantibodies in the dog population, sera were collected from four groups of dogs; a population of dogs affected with spontaneous hypoadrenocorticism (n = 213), dogs affected with hyperadrenocorticism (n = 58), dogs with iatrogenic hypoadrenocorticism following trilostane therapy (n = 4) and a population of hospital patients with no evidence of endocrine or immune-mediated disease (n = 110). Here, CYP11A1 is linked to Cushing syndrome.