Testing for monogenic diabetes among children and adolescents with antibody-negative clinically defined Type 1 diabetes

Diabet Med. 2009 Oct;26(10):1070-4. doi: 10.1111/j.1464-5491.2009.02812.x.

Abstract

Aims: Monogenic diabetes is frequently misdiagnosed as Type 1 diabetes. We aimed to screen for undiagnosed monogenic diabetes in a cohort of children who had a clinical diagnosis of Type 1 diabetes but were pancreatic autoantibody-negative.

Methods: We studied 252 patients diagnosed clinically with Type 1 diabetes between 6 months and 17 years of age. Pancreatic autoantibodies [islet cell autoantibodies (ICA), glutamic acid decarboxylase antibodies (GADA) and/or insulinoma-associated antigen-2 antibodies (IA2A)] were absent in 25 cases (9.9%). The most frequent genes involved in monogenic diabetes [KCNJ11 and INS for neonatal diabetes and HNF1A and HNF4A for maturity-onset diabetes of the young (MODY)] were directly sequenced.

Results: Two of the 25 (8%) antibody-negative patients had de novo heterozygous mutations in INS; c.94G>A (G32S) and c.265C>T (R89C). The two patients presented with non-ketotic hyperglycaemia at 8 and 11 months of age. In contrast, the four antibody-positive patients who presented at a similar age (6-12 months) had a more severe metabolic derangement, manifested as ketosis in all four cases, with ketoacidosis in two. At ages 15 and 5 years, both INS mutation patients were prescribed a replacement dose of insulin with good glycaemic control [glycated haemoglobin (HbA(1c)) 7.0 and 7.2%]. No mutations were found in KCNJ11, HNF1A or HNF4A.

Conclusions: The identification of patients with monogenic diabetes from children with clinically defined Type 1 diabetes may be helped by clinical criteria including the absence of pancreatic autoantibodies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Antibodies / genetics*
  • Autoantibodies / blood*
  • Blood Glucose / metabolism*
  • Child
  • Child, Preschool
  • Diabetes Mellitus, Type 1 / diagnosis
  • Diabetes Mellitus, Type 1 / genetics*
  • Female
  • Genetic Variation
  • Glycated Hemoglobin A / metabolism*
  • Humans
  • Infant
  • Insulin / genetics*
  • Male

Substances

  • Antibodies
  • Autoantibodies
  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin