Ring Finger protein 213 (RNF213) has recently been identified as a susceptibility gene for MMD, whose apoptosis-inducing function may be negatively regulated by its ubiquitin ligase.8, 9, 10 However, mice lacking the RNF213 gene did not spontaneously develop MMD, indicating that the loss of function of RNF213 could not fully induce MMD.11 This evidence concerns the gene RNF213 and multiminicore myopathy.