Summary
The HLA haplotype segregation and autoantibody spectrum in 7 type I (insulin-dependent)
diabetic multiplex families of North Indian origin were determined. Of the total of
17 diabetic sibs, 7 shared both haplotypes and 3 shared one haplotype with the proband.
No HLA-non-identical sibs were observed. This distribution of haplotypes was nonrandom
(P ≅ 0.005). The mode of inheritance was compatible with an autosomal recessive model,
while a dominant model was unlikely. Pancreatic isletcell antibodies were found in
23.5% of affected sibs, but in no healthy family member. A high incidence of other
autoantibodies (parietal-cell and thyroglobulin/thyroid microsomal antibodies) was
detected in both the diabetic patients (26.3%), and in healthy first-degree relatives
(22.2%). These findings emphasize the role of HLA-linked genes and autoimmunity in
the pathogenesis of type I diabetes in North India.
Key-Words
Type I (Insulin-Dependent) Multiplex Families
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HLA
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Pancreatic Islet-Cell Antibodies
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Organ-Specific Antibodies