IGHA1 and inflammatory bowel disease: Intriguingly, these risk variants were observed to be associated with subphenotypes of IgAN, i.e., early age at onset, elevated Gd-IgA1 levels, severe hematuria, and advanced chronic kidney disease (CKD) stage., and in a concordant way, specific risk genotypes in IgAN were associated with decreased abundances of potentially beneficial microbes and increased abundances of potentially harmful microbes, as reported for IBD.