Genetic association of multiple sclerosis and HL-A determinants.

Segregation of HL-A haplotypes was analyzed in 10 families in which there were at least two cases of multiple sclerosis. In nine families, multiple sclerosis was associated with only one parental HL-A haplotype. Specific HL-A determinants associated with multiple sclerosis differed among the families, suggesting that another histocompatibility-linked factor, possibly a gene determining susceptibility (or lack of resistance) played an etiologic role.

Racial predilection in multiple sclerosis.

Comparisons between the geographic distribution of multiple sclerosis and the habitats of various racial groups showed that racial factors alone could not explain the increase in prevalence of the disease with latitude. Racially similar groups living in different areas had different frequencies of multiple sclerosis. Conversely, racially different groups, living in the same area, had similar prevalence rates of multiple sclerosis.