Hormones and MS: Risk factors, biomarkers, and therapeutic targets.

Sex differences in epidemiological, clinical, and pathological features of multiple sclerosis (MS) have been observed for decades, establishing a foundation for more recent progress in our understanding of their overall impact on the disease. In the ACTRIMS session on Hormones, Sex Chromosomes, and MS: Risk Factors, Biomarkers, and Therapeutic Targets, this progress was summarized in three presentations by pioneers in the field, revealing evidence that sex chromosomes, epigenetic factors, and sex hormones function as interactive determinants of disease risk and phenotype in a fashion dependent upon life stage, from prenatal development, childhood, and adolescence to adulthood and aging. Implications for the effects of puberty, pregnancy, menopause, and andropause on autoimmune and neurodegenerative mechanisms were discussed, along with potential applications of exogenous hormones. Although several limitations in current approaches and concepts were noted, current insights pave the way for future progress in our understanding of this enigmatic disease.