Early onset obesity and adrenal insufficiency associated with a homozygous POMC mutation

Congenital isolated ACTH deficiency is a rare condition. It is characterized by decreased plasma adrenocorticotropic hormone (ACTH) concentration resulting in adrenal insufficiency and consequently low serum cortisol concentration and lack of hyperpigmentation. These subjects show no ACTH response to exogenous corticotrophin releasing hormone (CRH) administration and have a normal pituitary morphology. Additionally, the other pituitary hormones are normal, unlike secondary adrenal insufficiency which can be associated with multiple pituitary hormone deficiencies. Congenital isolated ACTH deficiency may present in early neonatal period or in later childhood.ACTH is produced from the precursor molecule proopiomelanocortin (POMC), by the action of the cleavage hormone pro-hormone convertase 1 (PCSK1) when stimulated by CRH. The genes associated with congenital isolated ACTH deficiency are TBX19 (TPIT), PCSK1 (PC1) and POMC. Genetic mutations in CRH or its receptor have not been associated with isolated ACTH deficiency [1]. TBX19 is a cell restricted transcription factor required for terminal differentiation of pituitary corticotrophs and for expression of POMC. Typically, individuals with TBX19 mutations present with neonatal hypoglycemia and cholestatic jaundice and account for 73% of isolated ATCH deficiency [2]. PCSK1 (PC1) mutations are rare and have been described in two cases with obesity, abnormal glucose homeostasis, ACTH and gonadotropin deficiency and gastrointestinal abnormalities [3]. The classical clinical triad described with POMC mutations includes early onset obesity, hypocortisolism and red hair.We describe an individual with early onset obesity, adrenal insufficiency and a novel POMC mutation but without the typical pigmentary phenotype of red hair and pale skin.A 9 month old female presented with hypoglycemia and hyponatremia following a three day history of fever, emesis, poor oral intake and progressive lethargy. She was the first born child of non