Novel Melano-Cortin-2-Receptor Gene Mutation Presenting With Infantile Cholestasis: A Case Report

INTRODUCTION: For many years, congenital panhypopituitarism has been recognized to cause infantile cholestasis. However, the isolated cortisol deficiency as a cause of cholestasis and liver failure was rarely reported. CASE DESCRIPTION: A 32-days old male infant presented to the hepatology clinic with infantile cholestasis. His initial workup revealed alanine transaminase (ALT) level of 138 U/L, aspartate transaminase level of 76 U/L, total bilirubin (T.Bil) of 103 mmol/L, direct bilirubin of (D.Bil) 83 mmol/L, gamma-glutamyl transpeptidase (GGT) level of 28 U/L with normal prothrombin time (PT) of 13 seconds. One week later, the patient developed severe bronchiolitis necessitating mechanical ventilation associated with acute liver failure and worsening cholestasis. His ALT increased to 303.5 U/L and direct bilirubin increased to 204 mmol/L with prolongation of PT to 18.9 seconds reflecting derangement in synthetic liver functions. There was associated hypoglycemia, hyponatremia and high normal potassium level with a picture of adrenal insufficiency. Hormonal workup and genetic testing revealed isolated cortisol deficiency with a novel homozygous mutation c.763_764delAT (p. Met255ValfsX17) in Melanocortin 2 receptor gene (MC2R) and the patient was diagnosed as familial primary glucocorticoid deficiency. The patient was maintained on cortisol replacement therapy with the resolution of cholestasis and normalization of liver functions. CONCLUSIONS: Patients presenting with infantile cholestasis associated with documented hypoglycemia should alert pediatricians about the possibility of familial glucocorticoid deficiency and prompt investigation of adrenal function should be considered. Cortisol replacement therapy leads to the resolution of cholestasis.