ENST00000477489.1:c.232G>A
Variant summary
Our verdict is Likely benign. The variant received -4 ACMG points: 1P and 5B. PP3BP6BS1
The ENST00000477489.1(LDB3):c.232G>A(p.Ala78Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000495 in 1,613,004 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A78S) has been classified as Uncertain significance.
Frequency
Consequence
ENST00000477489.1 missense
Scores
Clinical Significance
Conservation
Publications
- myofibrillar myopathy 4Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- dilated cardiomyopathyInheritance: AD Classification: LIMITED Submitted by: ClinGen
- familial dilated cardiomyopathyInheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
- arrhythmogenic right ventricular cardiomyopathyInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_benign. The variant received -4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes  0.000237  AC: 36AN: 152146Hom.:  0  Cov.: 32 show subpopulations 
GnomAD2 exomes  AF:  0.000235  AC: 59AN: 251374 AF XY:  0.000243   show subpopulations 
GnomAD4 exome  AF:  0.000522  AC: 762AN: 1460740Hom.:  0  Cov.: 30 AF XY:  0.000472  AC XY: 343AN XY: 726738 show subpopulations 
Age Distribution
GnomAD4 genome  0.000236  AC: 36AN: 152264Hom.:  0  Cov.: 32 AF XY:  0.000175  AC XY: 13AN XY: 74438 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
not specified    Uncertain:1Benign:1 
Variant summary: LDB3 c.2092G>A (p.Ala698Thr) 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. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00023 in 251374 control chromosomes. The observed variant frequency is approximately 8-fold of the estimated maximal expected allele frequency for a pathogenic variant in LDB3 causing Dilated Cardiomyopathy phenotype (3.1e-05). c.2092G>A has been observed in individual(s) affected with Dilated Cardiomyopathy, without strong evidence for causality (Andreasen_2013, Haas_2015, Hershberger_2008, Li_2010, vanderMeulen_2022). These report(s) do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. Co-occurrences with other pathogenic variant(s) have been reported ( MYH7 c.709C>T , p.Arg237Trp), providing supporting evidence for a benign role (Hershberger_2008). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 23299917, 25163546, 19412328, 20590677, 36178741). ClinVar contains an entry for this variant (Variation ID: 36446). Based on the evidence outlined above, the variant was classified as likely benign. -
The Ala698Thr variant in LDB3 has been reported in 2 individuals with DCM, both of whom also carry an additional variant in another cardiomyopathy-associated ge ne (Hershberger 2008, Li 2010). This variant has also been identified by our lab oratory in 1 Native American individual with HCM and 1 African American infant w ith DCM. This variant has been identified in 6/8600 European American chromosome s by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSN P rs45577134). Computational prediction tools and conservation analysis suggest that this variant may impact the protein, though this information is not predict ive enough to determine pathogenicity. In summary, the clinical significance of the Ala698Thr variant is uncertain. -
not provided    Benign:2 
- -
In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 19412328, 20590677, 22337857, 23299917, 25163546, 30547036) -
Cardiomyopathy    Uncertain:1 
- -
Myofibrillar myopathy 4    Uncertain:1 
The LDB3 gene has multiple clinically relevant transcripts. This variant occurs in alternate transcript NM_007078.3, and corresponds to NM_001080116.1:c.*26876G>A in the primary transcript. This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 698 of the LDB3 protein (p.Ala698Thr). This variant is present in population databases (rs45577134, gnomAD 0.04%). This missense change has been observed in individual(s) with dilated cardiomyopathy (PMID: 19412328, 20590677, 25163546). This variant is also known as c.G1762A (p.A588T). ClinVar contains an entry for this variant (Variation ID: 36446). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Cardiovascular phenotype    Uncertain:1 
The p.A698T variant (also known as c.2092G>A), located in coding exon 12 of the LDB3 gene, results from a G to A substitution at nucleotide position 2092. The alanine at codon 698 is replaced by threonine, an amino acid with similar properties. This alteration was reported in two unrelated probands with dilated cardiomyopathy (DCM); however, both carried variants in other DCM-associated genes (Hershberger RE et al. Clin Transl Sci. 2008;1:21-6; Li D et al. Clin Transl Sci. 2010;3:90-7). This alteration has also been detected in DCM and cardiomyopathy genetic testing cohorts (Haas J et al. Eur Heart J, 2015 May;36:1123-35a; van Lint FHM et al. Neth Heart J, 2019 Jun;27:304-309). This variant has also been detected in an exome cohort, but cardiovascular history was not provided (Andreasen C et al. Eur. J. Hum. Genet. 2013;21:918-28). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Dilated cardiomyopathy 1C    Benign:1 
Based on the classification scheme VCGS_Germline_v1.1.1, this variant is classified as likely benign. Following criteria are met: 0105 - The mechanism of disease for this gene is not clearly established. (N) 0107 - This gene is known to be associated with autosomal dominant disease. (N) 0200 - Variant is predicted to result in a missense amino acid change from alanine to threonine. (N) 0251 - Variant is heterozygous. (N) 0302 - Variant is present in gnomAD <0.001 for a dominant condition (67 heterozygotes, 0 homozygotes). (P) 0502 - Missense variant with conflicting in-silico predictions and/or uninformative conservation. (N) 0600 - Variant is located in the annotated LIM zinc-binding 3 domain. (N) 0708 - Comparable variants have conflicting previous evidence for pathogenicity. p.(Ala703Ser) has one VUS entry in ClinVar. (N) 0806 - Moderate previous evidence of neutrality in unrelated individuals. Identified in multiple patients at VCGS with LQTS and Brugada syndrome. This variant has six VUS and one likely benign entry in ClinVar. (B) 0905 - No segregation evidence has been identified for this variant. (N) 1007 - No published functional evidence has been identified for this variant. (N) 1208 - Inheritance information for this variant is not currently available. (N) Legend: (P) – Pathogenic, (N) – Neutral, (B) – Benign -
Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at