Bias in parental transmission of the HLA-DR3 allele in Sardinian multiple sclerosis

The authors analyzed the female: male (F:M) ratio according to the HLA-DRB1-DQB1 genotype in a cohort of multiple sclerosis (MS) patients from Sardinia, where the disease is associated with DR3 and DR4. In the whole cohort of 1,097 patients, F:M ratio was 2.24; however, it was 2.88 in DR3/DR3 and 2.52 in DR3/DRX (X#DR3 and DR4) individuals. Parental transmission of DR3 and DR4, assessed in a set of 565 case-parent triads, showed evidence of paternal inheritance of DR3 in affected women, thus explaining the excess of females in the DR3 category.