Supplementary Data: Online Table 1a

Case:

CasePreviousTesting: Full sarcomere testing (MYBPC3, TNNT2, TNNI3, MYL2, MYL3, TPM1, ACTC1), Additional testing (ABCC9, ACTN2, ANKRD1, BAG3, CALR3, CRYAB, CSRP3, DES, DMD, DSC2, DSG2, DSP, EMD, GLA, JPH2, JUP, LAMA4, LAMP2, LMNA, MYH6, MYPN, MYOZ1, MYOZ2, PKP2, PLN, PRKAG2, RBM20, RYR2, SCN5A, SGCD, TAZ, TCAP, TMEM43, TNNC1, TTN, VCL and LDB3)

CaseGenotypingMethod: DNA isolated from peripheral blood, targeted enrichment, next-gen sequencing with panel of 46 genes

Variant: NM_000257.3(MYH7):c.1106G>A (p.Arg369Gln)

ClinVar: 42822, https://www.ncbi.nlm.nih.gov/clinvar/variation/42822/

gnomAD: n/a

CaseDCM-19: Male, 5 year diagnosis, Caucasian, Germany

CasePresentingHPOs: HP:0001644, HP:0001635 (Dilated cardiomyopathy, Heart failure)

HPOsFreeText: LVEDD at 74 mm, LV-Ejection Fraction at 20%, Cardiac Index at 2.38

CaseNotHPOs: N/A

NotHPOsFreeText: N/A

CaseAddInfo: Proband treated with VAD and ICD, Sporadic family history of cardiac disease, Proband also has a variant in NEXN, Patient is heterozygous for MYH7 variant

CaseGenotypingMethod: Using a Cardiomyopathy gene panel of 46 genes, the proband's DNA was screened for variants. Afterwards, the variants were classified based on pathogenicity and modeled using predictive software.

Variant: NM_000257.3:c.1106G>A (p.Arg369Gln)

ClinVar: 42822 https://www.ncbi.nlm.nih.gov/clinvar/variation/42822/

gnomAD: Not in gnomAD

Multiple Gene Variants

NEXN Variant

Variant: NM_144573.3:c.1955A>G (p.Tyr652Cys)

ClinVar: 326 https://www.ncbi.nlm.nih.gov/clinvar/variation/326/

gnomAD: European (Non-Finnish) 1.407e-4, Overall 7.859e-5 https://gnomad.broadinstitute.org/variant/1-78408441-A-G