Consistent with this hypothesis was our observation that glomerular CFHR5 was easily detectable in kidney biopsy specimens from the index case, median serum CFHR5 levels were low in individuals with C3 glomerulonephritis, and serum CFHR5 level in the index patient was lower than levels in other family members with the sequence variant, but no kidney disease. This evidence concerns the gene CFHR5 and glomerulonephritis.