The contribution of each parent to the adrenal insufficiency phenotype observed in Ocn–/– mice born from Ocn–/– parents was determined by crossing Ocn+/– males with Ocn–/– females or Ocn–/– males with Ocn+/– females and measuring circulating adrenal steroid hormones in their adult Ocn–/– progeny. The gene discussed is BGLAP; the disease is Adrenal insufficiency.