14-23418398-G-T
Variant summary
Our verdict is Likely benign. The variant received -12 ACMG points: 0P and 12B. BS4BA1
This summary comes from the ClinGen Evidence Repository: The c.3981C>A (p.Asn1327Lys) variant in MYH7 has been identified in 0.16% (FAF 95% CI; 24/10156) of Ashkenazi Jewish chromosomes in gnomAD v2.1.1 (https://gnomad.broadinstitute.org), which is a high enough frequency to be classified as benign based on thresholds defined by the ClinGen Inherited Cardiomyopathy Expert Panel (BA1; Kelly 2018 PMID:29300372). Based on criteria selected, this variant should be classified as benign; however, the expert panel felt that since frequency in other populations is not as elevated as in the Ashkenazi Jewish population, it warrants adjusting in the final classification to likely benign. Therefore, this variant is classified as likely benign for cardiomyopathy in an autosomal dominant manner. MYH7-specific ACMG/AMP criteria applied (Kelly 2018 PMID:29300372): BA1 with expert panel adjustment. LINK:https://erepo.genome.network/evrepo/ui/classification/CA014310/MONDO:0005045/002
Frequency
Consequence
NM_000257.4 missense
Scores
Clinical Significance
Conservation
Publications
- dilated cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- dilated cardiomyopathy 1SInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
- hypertrophic cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- hypertrophic cardiomyopathy 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
- MYH7-related skeletal myopathyInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
- myopathy, myosin storage, autosomal recessiveInheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
- myopathy, myosin storage, autosomal dominantInheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
- congenital myopathy 7A, myosin storage, autosomal dominantInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Ebstein anomalyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- hyaline body myopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- left ventricular noncompactionInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- arrhythmogenic right ventricular cardiomyopathyInheritance: AD Classification: LIMITED Submitted by: ClinGen
- congenital heart diseaseInheritance: AD Classification: LIMITED Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_benign. The variant received -12 ACMG points.
Variant Effect in Transcripts
ACMG analysis was done for transcript: NM_000257.4. You can select a different transcript below to see updated ACMG assignments.
RefSeq Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| MYH7 | NM_000257.4 | MANE Select | c.3981C>A | p.Asn1327Lys | missense | Exon 30 of 40 | NP_000248.2 | ||
| MYH7 | NM_001407004.1 | c.3981C>A | p.Asn1327Lys | missense | Exon 29 of 39 | NP_001393933.1 |
Ensembl Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| MYH7 | ENST00000355349.4 | TSL:1 MANE Select | c.3981C>A | p.Asn1327Lys | missense | Exon 30 of 40 | ENSP00000347507.3 | ||
| MYH7 | ENST00000713768.1 | c.3981C>A | p.Asn1327Lys | missense | Exon 30 of 41 | ENSP00000519070.1 | |||
| MYH7 | ENST00000713769.1 | c.3981C>A | p.Asn1327Lys | missense | Exon 29 of 39 | ENSP00000519071.1 |
Frequencies
GnomAD3 genomes AF: 0.0000986 AC: 15AN: 152180Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.000113 AC: 28AN: 247224 AF XY: 0.0000971 show subpopulations
GnomAD4 exome AF: 0.0000461 AC: 67AN: 1454010Hom.: 0 Cov.: 31 AF XY: 0.0000512 AC XY: 37AN XY: 722036 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000986 AC: 15AN: 152180Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4AN XY: 74346 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Benign:4
Given the co-occurrence of another variant in several cases, the failure to segregate, and the apparent presence of the variant at an appreciable frequency in multiple general population samples, including individuals of Ashkenazi Jewish ancestry, (reviewed below) we consider this variant probably benign and do not consider it appropriate for testing family members ("predictive genetic testing"). Note this includes this patient's data. Summary: -Seen in at least 14 presumably unrelated cases of HCM (2 published, 12 unpublished). -In 3 of 6 cases who had sequencing of at least MYH7, MYBPC3, and TNNT2 another variant (VUS or likely pathogenic) was present. - One proband carried a second variant in MYL2 (c.37G>A; p.Ala13Thr) (ClinVar: likely pathogenic by GeneDx (Aug 12, 2014) and a VUS by LMM (Mar 16, 2009)) - 36-year-old female proband with LVWT of 25 mm carried a second variant in MYBPC3 (c.3535G>A; p.Glu1179Lys) (ClinVar: a VUS by LMM (Jul 1, 2014) and CHOE (date of submission not reported), and likely pathogenic by GeneDx (May 21, 2014)) - 18-year-old proband with LVWT of 21 mm carried a second variant in PRKAG2 (c.866T>C; p.Val289Ala) (ClinVar: a VUS by GeneDx (Oct 4, 2012)) -Segregation data: LMM reports that in two families the variant failed to segregate with disease in another affected family member. A reported case is suspicious for failure to segregate (Houghs et al) -The variant is too common in Ashkenazi Jewish reference samples (ex. 19 of 4,800 individuals in gnomAD). Published cases: Hougs et al. (2005) and Jensen et al. (2013) reported this variant in 1 out of 92 European patients with HCM that were cared for in Copenhagen University Hospital in Copenhagen, Denmark, who underwent analysis of the MYH7, MYBPC3, TPM1, TNNT2, TNNI3, ACTC, MYL2, and MYL3 genes. The proband is a 46-year-old male with LVWT of 20 mm, who needed percutaneous transluminal septal myocardial ablation for treatment. This proband carried an additional variant in MYL2 gene (c.37G>A; p.Ala13Thr), which is classified as likely pathogenic by GeneDx (Aug 12, 2014) and a VUS by LMM (Mar 16, 2009) per ClinVar. He had a 49-year-old affected brother with LVWT of 14 mm, who carried the MYH7 variant, and was obese and hypertensive and thus may have had secondary hypertrophy and not HCM. His affected fraternal twin sister, who had LVWT of 23 mm, carried the MYL2 mutation, but did not carry the MYH7 variant; his deceased mother was affected, and was an obligate carrier for both of the variants; his 10-year-old unaffected son also carried both for the variants. No additional phenotypic information or variants were provided by the authors. Miller et al. (2012) reported this variant in 1 out of 46 patients with HCM that were cared for in Cincinnati Children's Hospital Medical Center in Cincinnati, OH, who underwent analysis of MYH7, TNNT2, TPM1, MYBPC2, TNNI3, MYL2, MYL3, ACTC, TTR, TNNC1, CAV3, LAMP2, GLA, PRKAG2, MTTC, MTTI, MTTK, LMNA, ZAS/LDB3, DES, SGCD, PLN, ACTC1, TNNI2, TAZ, TTR, MTTL1, MTTQ, MTTH, MTTS1, MTTS2, MTND1, MTND5, and MTND6 genes. Ancestry of the patient was not reported. The study cohort included ~79% non-Hispanic Caucasian, 12 % Black, <2 % Asian, and 7 % Hispanic patients. No additional phenotypic information or variants were provided by the authors. Xu et al. (2015) used whole exome sequencing (WES) to query the genetic cause of patients with "sporadic" HCM. Study was conducted on 74 Han Chinese patients with HCM who did not have mutations in the 8 sarcomere genes: MYH7, MYBPC3, TNNT2, TNNI3, TPM1, ACTC1, MYL2 and MYL3. The genes that were included are not as established in their cause of HCM: RYR2,CALM3, JPH2, PLN, SRI, CALR3 and CASQ2,AGK, COX15, GLA, FXN, PRKAG2, MRPL3, LAMP2, TAZ and SLC25A4. 94% of the targeted regions were covered at least 4x. The authors analyzed novel or rare variants in known HCM genes. Mutations in MYH7 were found in 2 patients even though they should have been filtered out. N1327K (p.Asn13
See Variant Classification Assertion Criteria.
The p.Asn1327Lys variant (rs141764279) has been previously reported to segregate with disease in a family with hypertrophic cardiomyopathy (Hougs 2005 and Jensen 2013); however, three out of four of the affected individuals also carried a variant in MYL2. In addition, this variant has been identified in cohorts of unrelated, presumably healthy individuals (Ng 2013 and Kapplinger 2014). This variant is listed in the Genome Aggregation Database (gnomAD) browser with a frequency of 0.2% in Ashkenazi Jewish individuals (identified in 20 out of 9950 chromosomes), which is higher than expected for a pathogenic variant in MYH7. It is listed in the ClinVar database (Variation ID: 36641) as likely benign according to multiple labs, including a ClinGen expert panel. Functional data demonstrated that the p.Asn1327Lys mutant MYH7 protein expressed in adult rat cardiomyocytes had reduced incorporation into sarcomeres; however, the mutant protein did not alter contractile properties, raising questions about the physiological relevance of this reduced incorporation (Wolny 2014). Based on these observations, the p.Asn1327Lys variant is classified as likely benign.
Primary familial hypertrophic cardiomyopathy Uncertain:3
Heterozygous variant NM_000257.4:c.3981C>A (p.Asn1327Lys) in the MYH7 gene was found on WES data in male proband (26 y.o., Caucasian) with un obstructive hypertrophic cardiomyopathy, who underwent a myoectomy. Additional candidate heterozygous variant NM_000256.3:c.1505G>A (p.Arg502Gln) (Class V of pathogenicity) in the MYBPC3 gene was found in this proband. Clinvar contains 20 entries for this variant. The variant is described in the literature in 3 patients with hypertrophic cardiomyopathy and in 12 unpublished patients (PS4_supporting). NM_000257.4:c.3981C>A (p.Asn1327Lys) is in the Genome Aggregation Database (gnomAD) v4.1.0 with total MAF=0.00005105 (Date of access 04-05-2024). A functional study supports the effect of this variant on protein (PM1): PMID: 24047955. Most in silico predictors are inconclusive in the results (varsome.com). In accordance with ACMG (2015) criteria this variant is classified as Variant of Uncertain Significance (VUS) with following criteria selected: PS4_supporting, PM1.
Low GERP score may suggest that this variant may belong in a lower pathogenicity class
Cardiomyopathy Benign:3
Cardiovascular phenotype Uncertain:1Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.
not specified Benign:2
Variant summary: MYH7 c.3981C>A (p.Asn1327Lys) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 5.1e-05 in 1540170 control chromosomes, predominantly at a frequency of 0.002 within the Ashkenazi Jewish subpopulation in the gnomAD database. The observed variant frequency within Ashkenazi Jewish control individuals in the gnomAD database is approximately 2 fold of the estimated maximal expected allele frequency for a pathogenic variant in MYH7 causing Hypertrophic Cardiomyopathy phenotype (0.001). c.3981C>A has been observed in individual(s) affected with Hypertrophic Cardiomyopathy as well as healthy controls (e.g. Houghs_2005, Kapplinger_2014, Ng_2013, Park_2022, Miller_2012, Jensen_2013, Xu_2015). One publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (Wolny_2013). The following publications have been ascertained in the context of this evaluation (PMID: 15483641, 23197161, 24510615, 23054336, 23861362, 34542152, 24047955, 26573135). ClinVar contains an entry for this variant (Variation ID: 36641). Based on the evidence outlined above, the variant was classified as likely benign.
p.Asn1327Lys in exon 30 of MYH7: This variant has been reported in 1 individual with HCM who carried a second variant of unknown significance, but did not segre gate with disease in 1 affected relative (Houghs 2005, Jensen 2013). It has also been identified by our laboratory in 9 individuals with HCM, but did not segreg ate with disease in 2 individuals from 2 families (LMM unpublished data). In vit ro functional studies provide some evidence that this variant may impact protein function (Wolny 2013). However, in vitro assays may not accurately represent bi ological function. While this variant is rare in the general population (1/8598 European American chromosomes in the NHLBI Exome Sequencing Project, http://evs. gs.washington.edu/EVS/; rs141764279), it appears to be common amongst Ashkenazi Jewish individuals with a prevalence that greatly exceeds that of HCM (5/282 chr omosomes, 1.8%; LMM unpublished data). In summary, the frequency of this variant in the Ashkenazi Jewish population and multiple occurrences of non-segregation with disease indicate this variant is likely benign, although a modifying effect cannot be ruled out.
Hypertrophic cardiomyopathy Benign:2
The c.3981C>A (p.Asn1327Lys) variant in MYH7 has been identified in 0.16% (FAF 95% CI; 24/10156) of Ashkenazi Jewish chromosomes in gnomAD v2.1.1 (https://gnomad.broadinstitute.org), which is a high enough frequency to be classified as benign based on thresholds defined by the ClinGen Inherited Cardiomyopathy Expert Panel (BA1; Kelly 2018 PMID:29300372). Based on criteria selected, this variant should be classified as benign; however, the expert panel felt that since frequency in other populations is not as elevated as in the Ashkenazi Jewish population, it warrants adjusting in the final classification to likely benign. Therefore, this variant is classified as likely benign for cardiomyopathy in an autosomal dominant manner. MYH7-specific ACMG/AMP criteria applied (Kelly 2018 PMID:29300372): BA1 with expert panel adjustment.
Myosin storage myopathy Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.
Congenital myopathy with fiber type disproportion;C1834481:Dilated cardiomyopathy 1S;C1842160:Myosin storage myopathy;C1850709:Myopathy, myosin storage, autosomal recessive;C3495498:Hypertrophic cardiomyopathy 1;C4552004:MYH7-related skeletal myopathy Uncertain:1
Hypertrophic cardiomyopathy 1 Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.
MYH7-related skeletal myopathy Benign:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign.
Ventricular fibrillation Benign:1
MYH7-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at