IFIH1 and type 1 diabetes mellitus: The T1D-protective G:C (Ala946) allele frequencies are 30%–50% in White people and 70%–80% in African and Asian people.38–42 Similarly, R843H results from a G:C-to-A:T bp substitution, and the A:T (H843) allele frequency is 30–40% in White people and Africans, and 70% in Asian people.38–42 Variants T946A and R843H are in strong linkage disequilibrium with each other,38,39,44 such that Ala946 is predominantly found with His843 and Thr946 with Arg843.42,44,45 We note that most human IFIH1 reference sequences contain the alleles encoding Ala946/His843.