An earlier study showed three genes including phospholipase C-like 1, B lymphoid tyrosine kinase and chemokine were associated with DM.[32] Recently, a large GWAS in the Caucasian population with systemic autoimmune diseases [33,34] identified 26 shared genome-wide significant loci, 22 of which were related to myositis.[35] Nevertheless, the previous genetic studies of DM only used a limited number of single nucleotide polymorphisms (SNPs) to focus on HLA- and immune disease-associated genes for pathogenic mutations. The gene discussed is BLK; the disease is immune system disorder.