In the congenital myopathy subgroup, 12 of 22 patients (54.5%) had disease-causing variants in RYR1 (n = 4), MYH7 (n = 3), TTN (n = 2), FHL1 (n = 1), NEB (n = 1), and SELENON (n = 1). This evidence concerns the gene RYR1 and congenital myopathy with cores.