Epigenetics and Sperm Abnormalities

Epigenetic regulation via multiple mechanisms (DNA methylation, histone modifications, and in some cases RNAs) is essential to cell function in humans. Among the various cell types found in humans, the sperm epigenome represents one of the most unique and specialized epigenetic landscapes known in biology. The unique nature of the sperm epigenome is likely indicative of this specialized cell type's unique and important function. Importantly, recent data suggests that the paternal epigenome is required for normal sperm function, fertility, embryogenesis, and even offspring health. These remarkable findings have come from observations that patients with compromised sperm epigenomes tend to have decreased fertility in general, but also have higher likelihood of having marked alterations to sperm function and poor pregnancy outcomes. Further, data have shown that fathers can even impact the health of their offspring without having gene mutations. Such findings are even more interesting when taken into context with the high level of epigenetic alterations that occur in the sperm with various forms of environmental or lifestyle exposures. Taken together, it is possible that the sperm epigenome can be altered based on lifestyles and various exposures that can accumulate over time and that these alterations have the potential to impact fertility, embryogenesis, and offspring phenotype.