No independent association between HSP70 gene polymorphism and IDDM

Area of Science:

• Immunogenetics
• Molecular Biology
• Autoimmunity Research

Background:

• Heat shock proteins (HSPs) are implicated in autoimmunity, with autoantibodies found in diseases like lupus and diabetes.
• HSP70 genes are located in the Major Histocompatibility Complex (MHC), suggesting a potential genetic link to autoimmune conditions.

Purpose of the Study:

• To investigate the association between a specific heat shock protein 70-2 (HSP70-2) gene polymorphism and insulin-dependent diabetes mellitus (IDDM).

Main Methods:

• Restriction-fragment-length polymorphism (RFLP) analysis of the HSP70-2 gene was performed in 29 families affected by IDDM.
• Two HSP70-2 alleles (8.5-kb and 9.0-kb) were identified using the PstI enzyme.

Main Results:

• The 8.5-kb HSP70-2 allele was significantly more frequent in diabetic haplotypes (62%) compared to control haplotypes (43%), P = 0.03.
• This association was linked to conserved extended haplotypes previously identified as diabetes-associated.
• A strong association was observed between the 8.5-kb allele and DR3 haplotypes (23/26 diabetic, 3/3 normal) compared to DR2 haplotypes (0/2 diabetic, 0/9 normal), P = 8 x 10(-7).

Conclusions:

• The HSP70-2 gene polymorphism, specifically the 8.5-kb allele, shows a significant association with IDDM, particularly in individuals with DR3 haplotypes.
• This finding supports a potential role for HSP70-2 in the genetic susceptibility to IDDM.