Understanding type 1 diabetes through genetics: Advances and prospects

Area of Science:

• Genetics
• Immunology
• Endocrinology

Background:

• Type 1 diabetes mellitus (T1DM) genetic predisposition is significantly influenced by the major histocompatibility complex (MHC) on chromosome 6p21.
• DQB1 is a key genetic marker for T1DM, with HLA-DRB1 genes playing a crucial role in disease association.

Purpose of the Study:

• To investigate the association of specific human leukocyte antigen (HLA) genes and haplotypes with Type 1 Diabetes Mellitus (T1DM) risk in the Indian population.
• To compare T1DM genetic risk factors in India with those observed in Caucasian and other populations.

Main Methods:

• Analysis of human leukocyte antigen (HLA) gene associations with T1DM using data from the All India Institute of Medical Sciences.
• Evaluation of relative risks associated with specific HLA-DRB1, DQB1, and HLA-B-DR3 haplotypes and genotypes in the Indian context.

Main Results:

• HLA-DR3 showed the strongest association with T1DM in the Indian cohort, unlike DR4 which was not significantly increased.
• HLA-DR10, 11, 13, and 15 exhibited a negative association, being reduced in T1DM patients.
• DR3-DQ2 haplotypes conferred a higher relative risk for T1DM in India compared to DR4-DQ8. The DQ2/DQ8 genotype showed a higher risk (>30) than DQ2/DQ2 (approx. 18).
• Specific HLA-B-DR3 haplotypes (B58-DR3, B50-DR3, B8-DR3) modulated T1DM susceptibility in India and globally.

Conclusions:

• The genetic landscape of T1DM in India is characterized by a strong association with HLA-DR3 and DQ2, differing from patterns in other populations.
• Understanding these specific genetic markers is crucial for risk assessment and the development of targeted interventions.
• T1DM TrialNet will facilitate future studies, including identifying at-risk relatives for novel therapeutic interventions.