HLA-C and type 1 diabetes mellitus: We chose to validate the method using MHC data because: (a) of the availability of overlapping HLA and SNP typing data from two earlier studies; and, (b) of the vast prior information available from this region including its significant population-level genetic polymorphism and the long-range haplotype sequence fixity in many populations (including among families with members that are affected by T1D).