Table 1 and 4

Case A12: Female, 21yo

DiseaseAssertion: HCM

FamilyInfo: positive family history

CaseHPOFreeText: interventricular septum thickness = 25.9mm, left ventricular end diastolic diameter = 32.0mm, left ventricular end systolic diameter = 18.4mm, left ventricular posterior wall thickness = 9.4mm, left atrium = 26.9mm, left ventricular ejection fraction = 75%

CasePreviousTesting: 12-lead ECG, echocardiography, full testing (MYBPC3, TNNT2, TNNI3, MYL2, MYL3, TPM1, ACTC1), additional testing (LMNA, PRKAG2, SCN5A, MYH6)

CaseGenotypingMethod: genomic DNA collected from peripheral whole blood samples, PCR, high-throughput sequencing using PGM Sequencing 400 kit, variants verified via Sanger Sequencing

Variant: NM_000257.3(MYH7):c.2155C>T (p.Arg719Trp)

ClinVar: 14104, https://www.ncbi.nlm.nih.gov/clinvar/variation/14104/

gnomAD: 0.00003185, https://gnomad.broadinstitute.org/variant/14-23895180-G-A

CaseMYH7-28: Australia

DiseaseAssertion: Hypertrophic Cardiomyopathy

FamilyInfo: N/A

CasePresentingHPOs: HP:0001639 (Hypertrophic cardiomyopathy)

HPOsFreeText: N/A

CaseNotHPOs: N/A

NotHPOsFreeText: N/A

CaseAddInfo: N/A

CasePreviousTesting: See Table 1

CaseGenotypingMethod: DNA was isolated from peripheral blood. Most participants underwent testing from the Illumina Cardiomyopathy Sequencing Panel, which includes 46 cardiomyopathy related genes. For others, whole exome sequencing or Sanger squencing was used. After the results were returned, variants were filtered for pathogenicity and rarity.

Variant: NM_000257.3:c.2155C>T (p.Arg719Trp)

ClinVar: 14104 https://www.ncbi.nlm.nih.gov/clinvar/variation/14104/

gnomAD: European (Non-Finnish) 6.481e-5, Overall 3.185e-5 https://gnomad.broadinstitute.org/variant/14-23895180-G-A

Supplementary Material 4

Case M-14: 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.2155C>T (p.Arg719Trp)

ClinVar: 14104, https://www.ncbi.nlm.nih.gov/clinvar/variation/14104/

gnomAD: 0.00003185, https://gnomad.broadinstitute.org/variant/14-23895180-G-A

Supplementary Material 4

Case M-15: 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.2155C>T (p.Arg719Trp)

ClinVar: 14104, https://www.ncbi.nlm.nih.gov/clinvar/variation/14104/

gnomAD: 0.00003185, https://gnomad.broadinstitute.org/variant/14-23895180-G-A

Supplementary Data, Table 2

Case: Australian

DiseaseAssertion: HCM

CaseHPOFreeText: maximum left ventricular wall thickness of ≥15 mm

CasePreviousTesting: electrocardiography, echocardiography, Full testing (MYBPC3, MYH7, TNNT2, TNNI3, TPM1, MYL2, MYL3, ACTC1)

CaseGenotypingMethod: DNA isolated from peripheral blood or buccal swabs, PCR, Sanger sequencing, segregation analysis, haplotype analysis of MYBPC3 and MYH7

Variant: NM_000257.3(MYH7):c.2155C>T (p.Arg719Trp)

ClinVar: 14104, https://www.ncbi.nlm.nih.gov/clinvar/variation/14104/

gnomAD: 0.00003185, https://gnomad.broadinstitute.org/variant/14-23895180-G-A