RYR1 and congenital myopathy with cores: Among patients whose biopsy was indicative a congenital myopathy, 10 received a genetic diagnosis with identification of pathogenic mutations in the following genes: MTM1 (three cases), RYR1 (one case), ACTA1 (one case), TNNT1 (one case), TPM3 (one case), TTN (one case), CFL2 (one case), and DNM (one case).