Supplementary Material 4

Case M-31: Japanese

DiseaseAssertion: idiopathic cardiomyopathy (HCM and DCM)

CasePreviousTesting: Clinical evaluation, chest radiography, electrocardiography, echocardiography, cardiac catheterization, full testing (MYBPC3, TNNT2, TNNI3, MYL2, MYL3, TPM1, ACTC1)

CaseGenotypingMethod: 8 sarcomeric genes amplified from genomic DNA via PCR then screened using bidirectional direct sequencing

Variant: NM_000257.3(MYH7):c.4721G>A (p.Arg1574Gln)

ClinVar: 228912, https://www.ncbi.nlm.nih.gov/clinvar/variation/228912/

gnomAD: 0.00001989, https://gnomad.broadinstitute.org/variant/14-23885445-C-T