For example, pathogenic mutations of many genes have rarely been identified and reported in infertile male patients, even though they are enriched in germ cells and their functions and mechanisms have been thoroughly studied with mouse inactivation models, like DND1, UTF1, PIWIL2, etc Also, proteins that interact with ELAVL2 in human or mouse testis are different, as revealed by our immunoprecipitation and mass spectrum results. The gene discussed is PIWIL2; the disease is Infertility.