HLA-DQβ57 in Hispanic patients with insulin-dependent diabetes mellitus

OBJECTIVE: The purpose of our study was to investigate the distribution of HLA-DQ β-chain amino acid residue 57 (HLA-DQβ57) as a genetic marker of susceptibility for insulin-dependent diabetes mellitus in the Hispanic population. STUDY DESIGN: Fifteen patients of Puerto Rican descent with juvenile-onset insulin-dependent diabetes mellitus underwent human leukocyte antigen typing for HLA-DOβ57 by polymerase chain reaction amplification of the target genomic DQ sequence followed by hybridization of the polymerase chain reaction product to phosphorus 32-labeled allele-specific oligonucleotide probes. A control. group of 44 Hispanic adults without diabetes who were undergoing human leukocyte antigen typing for tissue donation were concurrently typed for comparison. RESULTS: The Hispanic insulin-dependent diabetes mellitus group showed a significant increase in homozygosity for a non-aspartate amino acid (p = 0.023) over a control group of Hispanic subjects without diabetes. A high rate of heterozygosity for aspartate (53.3%) is found in Hispanic subjects with insulin-dependent diabetes mellitus as well. CONCLUSIONS: HLA-DQβ57 in the Hispanic population has a distribution distinct from HLA-DQβ57 in the Caucasian population. A single aspartate is not protective against insulin-dependent diabetes mellitus in Hispanic subjects.