CLCN1 and Thomsen and Becker disease: Observations that neither of the parents was reported to suffer from neuromuscular symptoms, while both of them were heterozygous carriers of the p.Arg894* CLCN1 variant and the mother also of the premutation-range CCTG allele provide molecular confirmation of recessive myotonia congenita, which is in line with clinical, molecular and genealogical findings in the patient/family.