Dominant or recessive RYR1 mutations are a common cause of congenital myopathies.8, 9 There is considerable phenotypic variability reported and a small subset have a more severe form characterized by a fetal akinesia syndrome,10, 11 including one fetus with compound heterozygous RYR1 missense variants that was terminated at 32 weeks' gestation.10 Cosegregation of the c.14130-2A>G and p.Ser3074Phe RYR1 variants in family 2 is consistent with linkage (maximal LOD score 1.9, the threshold for suggestive linkage). This evidence concerns the gene RYR1 and congenital myopathy with cores.