Does race matter for multiple sclerosis?

That race or ethnicity can influence the susceptibility or modify the course of human illnesses is potentially clinically useful but can also be controversial. If race and ethnicity influence illnesses, then the particular ways in which this occurs will inform diagnosis and prognosis, with important therapeutic implications. By contrast, race and ethnicity have been associated with health care disparities; further, race or ethnicity can be difficult to define. For example, while being African American has important implications for management of hypertension,¹ some studies showed that African Americans are less likely to receive cardiac catheterization, highlighting racial biases in health care.² In the United States, race and ethnicity are usually self-described; however, obtaining additional information on an individual's grandparents may reveal racial admixtures. If only for research purposes, how does one classify race and ethnicity in individuals with diverse background? Indeed, recent studies in African Americans with multiple sclerosis (MS) concluded that this population is on average 23% ± 14% Northern European ancestry as determined by use of single nucleotide polymorphisms that are informative of ancestral origin.³ Interestingly, the extent of African origin DNA is highly variable for self-described African Americans, highlighting …