5-112838814-A-G
Variant summary
Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2
The NM_000038.6(APC):c.3220A>G(p.Thr1074Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,050 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_000038.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -6 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
APC | ENST00000257430.9 | c.3220A>G | p.Thr1074Ala | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
ENSG00000258864 | ENST00000520401.1 | n.228+9842A>G | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152230Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000120 AC: 3AN: 250420Hom.: 0 AF XY: 0.00000739 AC XY: 1AN XY: 135356
GnomAD4 exome AF: 0.00000752 AC: 11AN: 1461820Hom.: 0 Cov.: 33 AF XY: 0.00000688 AC XY: 5AN XY: 727206
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152230Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74372
ClinVar
Submissions by phenotype
not provided Uncertain:3
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Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in a patient with hereditary polyposis (Dz et al., 2021); This variant is associated with the following publications: (PMID: 18199528, Dz2021[Case Report]) -
The APC c.3220A>G; p.Thr1074Ala variant (rs962456431), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 428104). This variant is only observed on 3 alleles in the Genome Aggregation Database, indicating it is not a common polymorphism. The threonine at codon 1074 is moderately conserved, but computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.18). The vast majority of pathogenic APC variants are truncating nonsense or frameshift variants (see InSiGHt, Kerr 2013). However, due to limited information, the clinical significance of this missense variant is uncertain at this time. References: Link to InSiGHt: https://www.insight-group.org/syndromes/adenomatous-polyposis/. Kerr SE et al. APC germline mutations in individuals being evaluated for familial adenomatous polyposis: a review of the Mayo Clinic experience with 1591 consecutive tests. J Mol Diagn. 2013 Jan;15(1):31-43. -
Hereditary cancer-predisposing syndrome Uncertain:3
The p.T1074A variant (also known as c.3220A>G), located in coding exon 15 of the APC gene, results from an A to G substitution at nucleotide position 3220. The threonine at codon 1074 is replaced by alanine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species, and alanine is the reference amino acid in other vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
This missense variant replaces threonine with alanine at codon 1074 of the APC protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 3/250420 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
BP1 c.3220A>G, located in exon 16 of the APC gene, is predicted to result in the substitution of threonine by alanine at codon 1074, p.(Thr1074Ala)(BP1).This variant is found in 3/267469 at a filtering allele frequency of 0.0003% in the gnomAD v2.1.1 database non-cancer data set. The SpliceAI algorithm predicts no significant impact on splicing. In addition, the variant was also identified in the ClinVar database (6x uncertain significance) but has not been reported in LOVD database. Based on currently available information, the variant c.3220A>G is classified as an uncertain significant variant according to ClinGen-APC Guidelines version v1. -
Familial adenomatous polyposis 1 Uncertain:1
This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 1074 of the APC protein (p.Thr1074Ala). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with APC-related conditions. ClinVar contains an entry for this variant (Variation ID: 428104). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt APC protein function with a negative predictive value of 95%. 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at