Supplementary Data: Online Table 2a

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.2710C>T (p.Arg904Cys)

ClinVar: 164316, https://www.ncbi.nlm.nih.gov/clinvar/variation/164316/

gnomAD: 0.000003977, https://gnomad.broadinstitute.org/variant/14-23893328-G-A

Case298: Female, 6 years onset, Japan, Asian

DiseaseAssertion: Left ventricular noncompaction

CasePresentingHPOs: HP:0030682 (Left ventricular noncompaction)

HPOsFreeText: Left Ventricular Ejection Fraction at 65%, LVDD-Z score at 2.1

CaseNotHPOs: HP:0011675 (Arrhythmia)

NotHPOsFreeText: Congenital heart disease with significant hemodynamic changes

CaseAddInfo: No family history

CasePreviousTesting: Genes tested include the 8 sarcomere genes as well as 65 more listed in Table S1.

CaseGenotypingMethod: Genomic DNA was extracted from whole blood from each of the probands. Next Generation Sequencing of 73 genes related to cardiac function was performed, incorporating PCR amplification, and any variants found were subjected to filtering for frequency and pathogenicity. Any variants suggested to be pathogenic were confirmed by Sanger sequencing afterwards.

Variant: NM_000257.3:c.2710C>T (p.Arg904Cys)

ClinVar: 164316 https://www.ncbi.nlm.nih.gov/clinvar/variation/164316/

gnomAD: Ashkenazi Jewish 9.921e-5, Overall 3.977e-6 https://gnomad.broadinstitute.org/variant/14-23893328-G-A