On January 10th, 2024, Barrie et al. published a landmark paper identifying the ancestral European origin of the high-risk, multiple sclerosis (MS) allele, HLA-DRB1*15:01. The authors hypothesize that Bronze Age, Yamnaya migration to, and their population of Scandinavia and the British Isles, accounts for the high incidence of MS in these regions, stemming from the geographical spread of HLA-DRB1*15:01 as evidenced by their data. These data further indicate that this immune-related allele likely underwent positive-selection pressures, suggesting that HLA-DRB1*15:01 may have conferred increased immunological resistance to zoonotic pathogens that the Yamnaya would have been exposed to from a lifestyle of sheep, goat, and cattle herding, as well as from the prevalent consumption of dairy products harvested from these animals. We wish to expand the scope of the Barrie et al. hypothesis to include the other gene that emerged in their extensive genomic analysis; the lactase persistence allele, LCT/MCM6, which allows adults to consume milk beyond childhood without adverse physical effects. We propose that, in addition to the Yamnaya spread of HLA-DRB1*15:01, their spread of LCT/MCM6 engendered a cultural propensity for milk consumption that may play a significant role in the present-day, global distribution of MS. Specifically, we hypothesize that lactose tolerance, and the prominent dairy consumption it enables, may expose individuals to the enteric, dairy-animal pathogen, Clostridium perfringens type B/D and its Epsilon neurotoxin that targets the precise brain tissues damaged during each MS relapse.