TGM4 autoantibodies are detected in subfertile adult male patients with autoimmune polyendocrine syndrome type 1, caused by mutations in autoimmune regulator (AIRE) gene [74]. Tgm4−/− mice are subfertile with defects in copulatory plug formation and seminal fluid viscosity [75]. Aire−/− mice develop TGM4 autoantibodies, compromised TGM4 secretion, prostatitis, and exhibit subfertility [74]. This evidence concerns the gene AIRE and autoimmune polyendocrine syndrome type 1.