Genetic Basis of Male and Female Infertility

Male and female infertility affects close to 50 million couples worldwide according to a recent World Health Organization estimate. Many of the 25-30% of couples with idiopathic infertility likely have a genetic etiology for their condition. Next-generation sequencing has identified many new putative causes of infertility in recent years, which are discussed in this chapter. Genetic and genomic causes of infertility can be divided into cytogenetic anomalies, gene defects, and epigenetic aberrances. The discussion of male infertility focuses on genetic factors impairing spermatogenesis and includes numerical chromosomal anomalies such as Klinefelter syndrome, structural chromosomal anomalies such as Y-chromosome microdeletions, certain single gene mutations, syndromic diseases, and epigenetic mutations. The discussion of female infertility includes chromosomal anomalies like Turner syndrome, as well as genetic and epigenetic mutations identified as causes of hypogonadotropic hypogonadism, premature ovarian insufficiency, endometriosis, and polycystic ovarian syndrome. In conclusion, new genetic testing methods have significantly advanced our knowledge of the genetic basis of male and female infertility. However, the list of known candidate abnormalities is not exhaustive, and further research is required to understand how each candidate mutation influences fertility.