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Cq1 Exon Polymorphisms in Caucasian and African American Systemic Lupus Erythematosus patients

Fawzi Irshaid Irshaid, Daniel Joseph Birmingham

    Pakistan Journal of Biological Sciences : PJBS
    |September 7, 2018
    PubMed

    Insights

    A specific C1QC gene variant (129GG genotype) offers protection against systemic lupus erythematosus (SLE) in Caucasians. This genetic association with SLE risk is race-dependent and requires further mechanistic investigation.

    Area of Science:

    • Immunogenetics
    • Molecular Biology
    • Human Genetics

    Background:

    • The C1q protein, crucial for immune function, comprises three chains (A, B, C) encoded by separate genes.
    • Genetic variations in C1Q genes are recognized risk factors for systemic lupus erythematosus (SLE).

    Purpose of the Study:

    • To investigate the association between single nucleotide polymorphisms (SNPs) in the coding regions of C1Q genes and the risk of developing SLE.
    • To identify specific genetic markers within C1Q genes that may influence SLE susceptibility.

    Main Methods:

    • Sequencing of C1q A, B, and C chain exons from leukocyte DNA of Caucasian and African American SLE patients and healthy controls.
    • Identification and analysis of single nucleotide polymorphisms (SNPs) using Phrap and Phred software.
    • Genotyping of identified SNPs in a larger cohort of SLE patients and controls via restriction fragment length polymorphism analysis to assess SLE association.

    Main Results:

    • Three synonymous SNPs were identified: 276G>A in C1QA, 66C>A in C1QB, and 129G>A in C1QC.
    • No significant differences in genotype or allele frequencies were observed for C1QA (276G>A) and C1QB (66C>A) SNPs between SLE patients and controls.
    • A significant difference in genotype frequencies for the C1QC 129G>A SNP was found in Caucasians, with the 129GG genotype being significantly overrepresented in healthy controls (P = 0.004).

    Conclusions:

    • The homozygous 129GG genotype of the C1QC gene is associated with protection against SLE onset in Caucasian populations.
    • This protective effect appears to be race-dependent, as it was not observed in African Americans.
    • The underlying biological mechanism for this observed association between the C1QC 129GG genotype and SLE protection remains to be elucidated.
    Abstract

    Keywords:
    Autoimmune diseaseLupuscomplement proteingenessynonymous SNPs

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