Fig. 1: The pedigree of the proband (IV-4).

HT corresponds to haplotype sharing of individuals encompassing the genomic coordinate of the variant in RYR1 (chr19:38,496,455 [hg38]). [−/+] refers to confirmed carriers of the genotype, and [−/−] refers to non-carriers, confirmed by Sanger sequencing. Individual II-2 does not carry the variant; however, she shares the same haplotype background as individual II-5 (a confirmed carrier of the variant with 22 reads for reference allele and 6 for alternative allele). This implies that p.(Cys2237Tyr) led to mosaicism that occurred in the paternal grandmother (II-5) of proband. The years of birth and death of family members in generation I and II are 5-year rounded.