Epigenetic disorders and male subfertility

ObjectiveTo provide a link between epigenetics and male subfertility at the DNA, histone-protamine, and RNA levels and its consequences on fertilization and embryo development.DesignReview of the relevant literature.SettingUniversity-based clinical and research laboratories.Patient(s)Fertile and infertile men.Intervention(s)None.Main Outcome Measure(s)Critical review of the literature.Result(s)Epigenetic markers can be modified in infertile patients. Epigenetic modifications include methylation loss or gain on the global level and on imprinted genes, high levels of histone retention in spermatozoa, and deficiencies in some transcripts involved in spermatogenesis. Interestingly, these abnormalities are all linked together, because DNA methylation maintenance depends on DNA histone-protamine configuration which itself is stabilized by spermatozoal RNAs.Conclusion(s)The paternal genome has long been considered to be silent and passive in embryo formation. The epigenetic processes associated with the paternal DNA genome highlights its importance in male fertility as well as for embryo development.