Anti‐NT5C1A antibody seropositive IBM patients had a higher frequency of finger flexion weakness (91% vs. 76%; P < 0.01), but no significant differences were seen with regard to age at onset, maximum CK level, dysphagia, or complications of other autoimmune diseases/sarcoidosis/malignancy (Table 3, Table S3). This evidence concerns the gene NT5C1A and sarcoidosis.