NM_001999.4:c.8282C>T
Variant summary
Our verdict is Benign. Variant got -11 ACMG points: 0P and 11B. BP4_ModerateBP6BS1BS2
The NM_001999.4(FBN2):c.8282C>T(p.Ala2761Val) variant causes a missense change. The variant allele was found at a frequency of 0.000216 in 1,614,010 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).
Frequency
Consequence
NM_001999.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -11 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000217 AC: 33AN: 152228Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.000207 AC: 52AN: 251164Hom.: 0 AF XY: 0.000251 AC XY: 34AN XY: 135718
GnomAD4 exome AF: 0.000216 AC: 316AN: 1461782Hom.: 0 Cov.: 31 AF XY: 0.000198 AC XY: 144AN XY: 727192
GnomAD4 genome AF: 0.000217 AC: 33AN: 152228Hom.: 0 Cov.: 33 AF XY: 0.000202 AC XY: 15AN XY: 74370
ClinVar
Submissions by phenotype
Congenital contractural arachnodactyly Uncertain:2Benign:2
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
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Based on the classification scheme VCGS_Germline_v1.1.1, this variant is classified as VUS–3C. Following criteria are met: 0102 - Loss-of-function is a known mechanism of disease for this gene. (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 valine (exon 64). (N) 0251 - Variant is heterozygous. (N) 0302 - Variant is present in gnomAD <0.001 for a dominant condition (55 heterozygotes, 0 homozygotes). (P) 0503 - Missense variant consistently predicted to be tolerated or not conserved in mammals with a minor amino acid change. (B) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. (N) 0705 - No comparable variants have previous evidence for pathogenicity. (N) 0804 - Variant previously been described as variant of uncertain significance (VUS). Six VUS entries in ClinVar. Previously observed in the VCGS cardiomyopathy cohort. (N) 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 -
not provided Uncertain:2Benign:1
The p.Ala2761Val variant (rs201962592) has not been reported in the medical literature, gene specific variation databases, but it has been reported to ClinVar (see link below). This variant is listed in the Exome Aggregation Consortium Browser with a population frequency of 0.03 percent (identified on 20 out of 66,740 chromosomes) in non-Finnish European population. The alanine at position 2761 is highly conserved (up to Chicken, considering 11 species) (Alamut v.2.8.1) but Zebra-finch has valine at this position, and this non-cysteine residue is not located in the EGF-like domain. Computational analyses of the effects of the p.Ala2761Val variant on protein structure and function provide conflicting results (SIFT: tolerated, MutationTaster: disease causing, PolyPhen-2: benign). Our laboratory has previously identified this variant in one individual with bifid uvula, submucous cleft, micrognathia, facial asymmetry, joint hypermobility, tracheomalacia, conductive hearing loss and developmental delay. Altogether, there is not enough evidence to classify the p.Ala2761Val variant with certainty. -
Has not been previously published as pathogenic or benign to our knowledge; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18767143) -
FBN2: BP4 -
Familial thoracic aortic aneurysm and aortic dissection Uncertain:1
The p.A2761V variant (also known as c.8282C>T), located in coding exon 64 of the FBN2 gene, results from a C to T substitution at nucleotide position 8282. The alanine at codon 2761 is replaced by valine, an amino acid with similar properties, and is located in the fibulin-like domain. This amino acid position is not well conserved in available vertebrate species, and valine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
See cases Uncertain:1
ACMG classification criteria: PM2, BP4 -
Connective tissue disorder Uncertain:1
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not specified Benign:1
Variant summary: FBN2 c.8282C>T (p.Ala2761Val) results in a non-conservative amino acid change in the encoded protein sequence. Two of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00021 in 251164 control chromosomes (gnomAD v2.1). The observed variant frequency is approximately 165-fold of the estimated maximal expected allele frequency for a pathogenic variant in FBN2 causing Aortopathy phenotype (1.3e-06), strongly suggesting that the variant is benign. To our knowledge, no occurrence of c.8282C>T in individuals affected with Aortopathy and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 213370). Based on the evidence outlined above, the variant was classified as likely benign. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at