NM_000038.6:c.5635G>T
Variant summary
Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4BP6
The NM_000038.6(APC):c.5635G>T(p.Ala1879Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000088 in 1,613,704 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. A1879T) has been classified as Uncertain significance.
Frequency
Consequence
NM_000038.6 missense
Scores
Clinical Significance
Conservation
Publications
- classic or attenuated familial adenomatous polyposisInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- desmoid tumorInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
- familial adenomatous polyposis 1Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
- gastric adenocarcinoma and proximal polyposis of the stomachInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
- sarcomaInheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- APC-related attenuated familial adenomatous polyposisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Turcot syndrome with polyposisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Cenani-Lenz syndactyly syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| APC | NM_000038.6 | c.5635G>T | p.Ala1879Ser | missense_variant | Exon 16 of 16 | ENST00000257430.9 | NP_000029.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152090Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000279 AC: 7AN: 250890 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000917 AC: 134AN: 1461614Hom.: 0 Cov.: 66 AF XY: 0.0000866 AC XY: 63AN XY: 727110 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152090Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74284 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:4Benign:1
The APC p.Ala1861Ser variant was identified in dbSNP (ID: rs587779799), ClinVar (classified as likely benign by Ambry Genetics and as a VUS by GeneDx, Invitae, Counsyl and Color for familial adenomatous polyposis 1 and hereditary cancer-predisposing syndrome) and Cosmic (FATHMM prediction of pathogenic; score=0.99) but was not identified in LOVD 3.0. The p.Ala1861Ser (alias p.A1879S) variant was identified in 1/1260 individuals undergoing Lynch syndrome testing and classified as a VUS, and was identified in a cohort of 1120 patients with pediatric cancers (Yurgelun_2015_PMID: 25980754; Zhang_2015_PMID: 26580448). The variant was identified in control databases in 8 of 282274 chromosomes at a frequency of 0.000028 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: East Asian in 2 of 19936 chromosomes (freq: 0.0001), African in 1 of 24908 chromosomes (freq: 0.00004) and European (non-Finnish) in 5 of 128744 chromosomes (freq: 0.000039); it was not observed in the Latino, Ashkenazi Jewish, European (Finnish), Other and South Asian populations. The variant occurs outside the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. The p.Ala1861 residue is conserved in in mammals but not in more distantly related organisms however computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM) do not suggest a high likelihood of impact to the protein; this information is not predictive enough to rule out pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance.
The APC c.5635G>T (p.Ala1879Ser) variant has been reported in the published literature in an individual with suspected Lynch syndrome (PMID: 25980754 (2015)), and individuals with breast cancer (PMID: 35534704 (2022), 34326862 (2021)). The frequency of this variant in the general population, 0.000039 (5/128744 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is deleterious or benign. Based on the available information, we are unable to determine the clinical significance of this variant.
This variant is associated with the following publications: (PMID: 25980754, 26580448, 27329244)
APC: PM2:Supporting, BP1
Familial adenomatous polyposis 1 Uncertain:2Benign:1
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.
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.
Hereditary cancer-predisposing syndrome Uncertain:1Benign:2
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.
Classic or attenuated familial adenomatous polyposis Uncertain:1
This missense variant replaces alanine with serine at codon 1879 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). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with Lynch syndrome associated cancer and/or polyps (PMID: 25980754) and in an individual affected with acute lymphoblastic leukemia (PMID: 26580448). This variant has also been identified in 8/282274 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.
not specified Benign:1
Variant summary: APC c.5635G>T (p.Ala1879Ser) results in a conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 8.8e-05 in 1613704 control chromosomes, predominantly at a frequency of 0.00012 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 1.68 fold of the estimated maximal expected allele frequency for a pathogenic variant in APC causing Familial Adenomatous Polyposis phenotype (7.1e-05). c.5635G>T has been observed in settings of multigene panel testing in individuals affected with or suspected of hereditary cancer syndromes such as Lynch Syndrome or Hereditary Breast and Ovarian Cancer Syndrome, but without strong evidence for causality (e.g. Yurgelun_2015, Bhai_2021, de Oliveira_2022, Barati_2024). These reports do not provide unequivocal conclusions about association of the variant with Familial Adenomatous Polyposis or other ATM-related disorders. 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: 39148954, 34326862, 25980754, 26580448, 35534704). ClinVar contains an entry for this variant (Variation ID: 127307). 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