HMGCR and Menkes disease: For instance, in two series studies with Japanese cohorts, one showed that more than half of the patients with anti‐HMGCR antibody had disease duration of more than 2 years, and the other study showed that all 5 anti‐HMGCR‐positive JIIM had over 3 years of disease duration and 4 of these 5 patients even had disease course longer than 10 years of mimicking muscular dystrophy (MD),8, 11 while two separate studies of Chinese and American cohorts reported 60% and 100% anti‐HMGCR‐positive JIIM showed acute onset, respectively.5, 10