While the prevalence of RNF213 deleterious variants in our MMD patients (31%) lies either above or in line with what was detected in mixed pediatric/adult populations [14, 15], Guey et al. [13], found RNF213 rare coding variants in 48% of their smaller (N = 21) sub-cohort of pediatric and familial cases. This evidence concerns the gene RNF213 and multiminicore myopathy.