Abstract 505
Poster Session II, Sunday, 5/2 (poster 205)
Mutations in the insulin gene cause the autosomal recessive disorders Leprechaunism and Rabson-Mendenhall syndrome. Here we report a child who presented at 4 weeks of age with hyperglycemia and extreme hyperinsulinemia (2776 µU/ml). Other features included intrauterine growth retardation (birth weight 2.16 kg at term), post-natal failure to thrive, acanthosis nigricans, dysplastic teeth, thick hair, absent subcutaneous fat, and large genitalia, all findings consistent with a diagnosis of Rabson-Mendenhall syndrome. He also developed chronic hip arthralgia, felt to represent a variant of idiopathic toxic synovitis. During the first three years of life, his blood glucose levels ranged from normal to ∼400 mg/dL while his hemoglobin (Hb) A1C ranged from 5.8% to 8.1%. At 3.7 years of age he was started on glipizide 2.5 mg/day. Metformin was added subsequently for worsening glycemic control. Despite this regimen maintaining HbA1C values of 8-9%, he developed unexpected sequelae, including microalbuminuria, persistent ketonuria, and progressive decline in weight gain and linear growth. During the last 3 years, he had normal to low values for IGF-1 (36-50 ng/ml), IGF-BP3 (0.9-1.8 mg/l). and IGF-BP1 (60-62 ng/ml). Currently he is 7.2 years old with a height at -3.5 SD for age. He is on a trial of growth hormone (GH), which seems to aggravate hyperglycemia (HbA1C of 10.6%), without yet affecting growth velocity. IGF-1 therapy will be considered following completion of the GH trial.
