Although no associations were identified at genome-wide significance in the whole IIM cohort, polymyositis, or dermatomyositis groups, WDFY4 rs7919656 was significantly associated with CADM (OR = 3.87, 95% CI 2.23–6.55, p = 1.5 × 10−8), albeit in a small sample size. This evidence concerns the gene WDFY4 and clinically amyopathic dermatomyositis.