RNF212B and Infertility: To begin exploring possible molecular mechanisms underlying infertility in men carrying the RNF212BC448T variant, we first examined tissue expressions of both RNF212B and its paralog RNF212. Whereas in human tissues, RNF212B RNA is almost exclusively expressed in the testis, RNF212 (OMIM: 612041) expression is more general, displaying relatively elevated levels in the testis and the ovary but also in several somatic tissues (Figure S3).