5-112839927-A-G
Variant summary
Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4BS2
The NM_000038.6(APC):āc.4333A>Gā(p.Thr1445Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000155 in 1,613,938 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000038.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -5 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
APC | ENST00000257430.9 | c.4333A>G | p.Thr1445Ala | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
ENSG00000258864 | ENST00000520401.1 | n.228+10955A>G | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 |
Frequencies
GnomAD3 genomes AF: 0.0000132 AC: 2AN: 152082Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000119 AC: 3AN: 251176Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135738
GnomAD4 exome AF: 0.0000157 AC: 23AN: 1461856Hom.: 0 Cov.: 33 AF XY: 0.0000206 AC XY: 15AN XY: 727222
GnomAD4 genome AF: 0.0000132 AC: 2AN: 152082Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74288
ClinVar
Submissions by phenotype
Familial adenomatous polyposis 1 Uncertain:4
This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
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This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 1445 of the APC protein (p.Thr1445Ala). This variant is present in population databases (rs587780597, gnomAD 0.003%). This missense change has been observed in individual(s) with colorectal adenomas (PMID: 18199528). ClinVar contains an entry for this variant (Variation ID: 135702). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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. -
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Hereditary cancer-predisposing syndrome Uncertain:1Benign:2
BS1, BP1 c.4333A>G located in exon 16 of the APC gene, is predicted to result in the substitution of threonine by alanine at codon 1445, p.(Thr1445Ala)(BP1). This variant is found in 4/117964 at a filtering allele frequency of 0.0011% in the gnomAD v2.1.1 database (European non-Finnish non-cancer data set)(BS1). The SpliceAI algorithm predicts no significant impact on splicing. In addition, the variant was also identified in the ClinVar database (7x uncertain significance, 1x likely benign) but it has not been identified in the LOVD database. Based on currently available information, the variant c.4333A>G is classified as a likely benign variant according to ClinGen-APC Guidelines version v1. -
The p.T1445A variant (also known as c.4333A>G), located in coding exon 15 of the APC gene, results from an A to G substitution at nucleotide position 4333. The threonine at codon 1445 is replaced by alanine, an amino acid with similar properties. In a cohort of 691 North Americans with multiple colorectal adenomas (CRAs), this alteration was detected in an individual with less than 10 CRAs (Azzopardi D et al. Cancer Res. 2008 Jan;68:358-63). This alteration has also been reported in breast cancer patients who underwent hereditary multigene panel testing (Tung N et al. Cancer, 2015 Jan;121:25-33; Guindalini RSC et al. Sci Rep, 2022 Mar;12:4190). This amino acid position is not well conserved in available vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Missense alterations in APC are not a common cause of disease (Spier I et al. Genet Med. 2024 Feb;26(2):100992). Based on the available evidence, the clinical significance of this variant remains unclear. -
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not provided Uncertain:2
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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 individuals with personal or family history of colorectal cancer and/or polyps referred for genetic testing at GeneDx and in the published literature (Azzopardi et al., 2008); This variant is associated with the following publications: (PMID: 21859464, 27882345, 25186627, 18199528, 35264596) -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at