Allotypes of the fourth component of complement in Koreans

Area of Science:

• Genetics
• Immunogenetics
• Population Genetics

Background:

• The complement system, particularly the C4 gene, plays a crucial role in immune responses.
• Understanding C4 allotype frequencies is important for population genetics and disease association studies.
• Previous research indicates ethnic variations in C4 allele distributions.

Purpose of the Study:

• To determine the allele frequencies of C4A and C4B in a healthy Korean population.
• To compare these frequencies with those reported in other ethnic groups.
• To identify any unique or characteristic C4 alleles in Koreans.

Main Methods:

• Genetic polymorphism analysis of C4 was conducted on EDTA-plasma samples from 169 healthy, unrelated Koreans.
• High-voltage agarose gel electrophoresis and immunofixation were used for plasma sample analysis.
• Hemolytic overlay method was employed for further detection of C4B allotypes.

Main Results:

• The most frequent C4A allele was C4A*3 (0.6099), followed by C4A*4 (0.1702).
• The most frequent C4B allele was C4B*1 (0.6406), followed by C4B*2 (0.2740).
• The C4B*5 allele, common in Asians and rare in Caucasoids/Negroids, was identified as characteristic of East Asian populations. Duplicated allotypes were observed in both C4A and C4B loci.

Conclusions:

• C4A*3 and C4B*1 are the predominant alleles in the studied Korean population.
• The presence of C4B*5 highlights its significance as an East Asian characteristic allele.
• The findings contribute to the understanding of C4 gene diversity in East Asian populations.