Since analyzing the rs2476601 single-nucleotide polymorphism (SNP) within the PTPN22 gene revealed no polymorphism in the Japanese, we analyzed four SNPs, rs2358994 (in BCL2L15), rs2153977 (in MAGI3), rs1111695 (in PHTF1), and rs7679475 (in GPR103) genotypes in a case–control study based on 447 Japanese AITD patients [277 Graves’ disease (GD) and 170 Hashimoto’s thyroiditis (HT) patients] and 225 matched Japanese controls using the high-resolution melting and unlabeled probe methods. This evidence concerns the gene MAGI3 and hematocrit.