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Little is known about auxologic,
autoimmune, and HLA characteristics specific to children with
early-onset diabetes (EOD). In this paper 40 children with a mean CA
of 2.6 years who developed diabetes mellitus before 5 years of age
were studied. These patients were compared with a matched subgroup of
children of mean age of 9.9 years, therefore, with later onset
diabetes mellitus (LOD). Auxologic data and antibody radioimmunoassay
data from medical records were retrospectively analyzed. HLA diabetes
related class II alleles were typed and evaluated for comparison
between "whites" and "Hispanics" . The frequencies of glutamic acid
decarboxylase (GAD) and islet cell antibodies (ICA) were significantly
lower in the EOD group than in the group developing diabetes at an
older age. No significant differences were detectable for insulin
auto-antibodies (IAA), thyroid peroxidase, and thyroglobulin
antibodies. None of the patients of the EOD group developed
hypothyroidism, whereas 20% of the LOD patients did. There was a
negative correlation between GAD antibodies and the predisposing
haplotype DR3/DQ2. None of the EOD patients had either of the
protective alleles (DRB1*1501 or DQB1*0602) for diabetes. There were
significant differences in the frequencies of some diabetes related
HLA alleles between EOD patients and a large non-age stratified type 1
diabetes group. The pertinent clinical information, frequency of
autosomal markers and HLA data among ethnic groups are below (Tables
1-3). The authors concluded that children with EOD have different
diabetes related autoimmune and genetic characteristics from those
diagnosed later on in life. Hathout EH et al. Pediatrics
2003;111:860-863.
Editor’s Comment: Very young children with diabetes mellitus
are known to have a more severe course than those diagnosed later in
life. The difficulties in the control of the disease among the younger
patients may account for more frequent and more severe complications
of the disease occurring earlier in life. However, the data in this
paper are suggestive that there are autoimmune and genetic differences
among type 1 diabetic patients according to age (early vs late onset),
and these may account for the differences in the control and the
outcome of the disease. Chromosomal abnormalities (parental isodisomy
of chromosome 6) also have been described among patients with the
transient form of neonatal diabetes.1 Studies like these
suggest that EOD probably is not classic type 1 diabetes mellitus, and
thus may require unique approaches for prevention and therapy.
Fima Lifshitz, MD
Reference
1. Metz C et al. J Pediatr 2002;141:483-489. |
