Variants in Complement Factor H and Complement Factor H-Related Protein Genes, CFHR3 and CFHR1, Affect Complement...

Area of Science:

• Nephrology
• Immunology
• Genetics

Background:

• Complement activation is prevalent in IgA nephropathy (IgAN) and linked to disease severity.
• Genome-wide association studies identified IgAN susceptibility loci on 1q32, including complement regulatory genes CFH and CFHR1-5.

Purpose of the Study:

• To investigate the clinical impact of variations in CFH, CFHR3, and CFHR1 on IgAN susceptibility and progression.
• To correlate genetic findings with clinical phenotypes and complement system activity.

Main Methods:

• Genotype-phenotype correlation analysis in 1178 IgAN patients (Group 1).
• Linkage analysis and assessment of serum complement levels in 365 IgAN patients with follow-up data (Group 2).
• Measurement of serum CFH, C3, C3a, and galactose-deficient IgA1.

Main Results:

• The rs6677604 polymorphism in CFH was associated with mesangial C3 deposition.
• The rs6677604-A allele linked with CFHR3-1 deletion, higher serum CFH, and lower C3a levels.
• CFH levels correlated positively with C3 and negatively with mesangial C3 deposition; pathogenic IgA1 glycoform associated with C3 deposition.

Conclusions:

• Genetic variants in CFH, CFHR3, and CFHR1 influence complement activation pathways in IgAN.
• These genetic variations contribute to IgAN susceptibility and disease progression.
• Complement dysregulation driven by these genetic factors plays a key role in IgAN pathogenesis.