Johanson-blizzard syndrome: loss of glucagon secretion response to insulin-induced hypoglycemia.

Johanson-Blizzard syndrome is a rare autosomal recessive disorder characterized by aplasia of the alae nasi, aplasia cutis, dental anomalies, postnatal growth retardation and pancreatic exocrine aplasia. Some endocrinological dysfunctions--growth hormone (GH) deficiency, hypothyroidism, and diabetes mellitus--are known to complicate this syndrome. We report here a Japanese infant with Johanson-Blizzard syndrome presenting with failure to thrive. Endocrinological examination by insulin-induced hypoglycemia showed not only the presence of GH deficiency, but also the loss of the glucagon secretion response to hypoglycemia. This complication suggests abnormal input of autonomic nerves to the islets of pancreas in Johanson-Blizzard syndrome.