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Polymorphism of complement C4 and susceptibility to IDDM and microvascular complications
K Lhotta1, M Auinger, F Kronenberg
1Department of Internal Medicine, Innsbruck University Hospital, Vienna, Austria.
Diabetes Care
|January 1, 1996
Summary
The C4 null allele C4AQ0 is associated with type 1 diabetes (IDDM). However, complement C4 gene variations do not appear to increase the risk for microvascular complications in IDDM patients.
Area of Science:
- Immunogenetics
- Endocrinology
- Diabetology
Background:
- The complement system, particularly complement C4 (C4), plays a role in immune responses.
- Previous studies suggested a link between C4 gene polymorphism and susceptibility to type 1 diabetes (IDDM).
- The association of C4 polymorphism with microvascular complications in IDDM remains unclear.
Purpose of the Study:
- To investigate the association between inherited complement C4 polymorphism and genetic susceptibility to IDDM.
- To determine if C4 polymorphism is linked to microvascular complications in IDDM patients.
Main Methods:
- C4 allotypes were determined in 241 IDDM patients and 140 healthy controls using agarose gel electrophoresis and immunoprecipitation.
- C4 allotype frequencies were compared between patient and control groups.
- Frequencies were also compared between IDDM patients with and without nephropathy or retinopathy.
Main Results:
- Significant differences in C4A and C4B loci were observed between IDDM patients and healthy controls.
- The C4 null allele (C4AQ0) was significantly increased in IDDM patients (26.8% vs. 11.8%).
- No significant differences in C4 allotype distribution were found between IDDM patients with or without microvascular complications.
Conclusions:
- This study confirms the association between the C4 null allele (C4AQ0) and IDDM.
- The findings do not support a role for inherited C4 polymorphism in the genetic susceptibility to microvascular complications in IDDM.
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