Histocompatibility antigens in diabetic identical twins

Area of Science:

• Immunogenetics
• Endocrinology
• Twin Studies

Background:

• Type 1 diabetes (T1D) has a genetic component, with human leukocyte antigen (HLA) genes being significant contributors.
• Identical twin studies are crucial for dissecting genetic versus environmental influences on complex diseases like diabetes.

Purpose of the Study:

• To investigate the association of specific human leukocyte antigen (HLA) alleles with diabetes concordance and discordance in identical twins.
• To explore potential differences in genetic predisposition between maturity-onset and juvenile-onset diabetes within twin pairs.

Main Methods:

• Human leukocyte antigen (HLA) typing was performed on 84 pairs of identical twins with diabetes.
• Diabetic twin pairs were categorized based on age of onset (maturity-onset vs. juvenile-onset) and concordance (both twins affected vs. only one affected).
• HLA antigen frequencies were compared between concordant and discordant twin pairs.

Main Results:

• Maturity-onset diabetic twins (n=22) were all concordant and showed no alterations in HLA frequencies.
• In juvenile-onset diabetic twins (n=62), the W15 antigen frequency was elevated in both concordant (31 pairs) and discordant (31 pairs) groups.
• The HL-A8 antigen frequency was increased only in concordant juvenile-onset diabetic twin pairs.

Conclusions:

• The increased frequency of W15 in discordant juvenile-onset diabetic twins suggests a general genetic predisposition to diabetes.
• The differential association of HL-A8 solely in concordant pairs indicates that specific HLA alleles may be linked to disease susceptibility in a subset of diabetic twins.
• These findings suggest that distinct genetic factors, potentially involving different HLA alleles, may underlie diabetes susceptibility in juvenile-onset diabetic identical twins.