5-112838441-G-T
Variant summary
Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBP6
The NM_000038.6(APC):c.2847G>T(p.Met949Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00007 in 1,614,178 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M949T) 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 -3 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| APC | NM_000038.6 | c.2847G>T | p.Met949Ile | missense_variant | Exon 16 of 16 | ENST00000257430.9 | NP_000029.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000375 AC: 57AN: 152196Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000478 AC: 12AN: 250790 AF XY: 0.0000443 show subpopulations
GnomAD4 exome AF: 0.0000383 AC: 56AN: 1461864Hom.: 0 Cov.: 33 AF XY: 0.0000344 AC XY: 25AN XY: 727224 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000374 AC: 57AN: 152314Hom.: 0 Cov.: 32 AF XY: 0.000524 AC XY: 39AN XY: 74496 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Familial adenomatous polyposis 1 Uncertain:2Benign:2
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.
This variant is considered likely benign. This variant has been observed at a population frequency that is significantly greater than expected given the associated disease prevalence and penetrance.
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.
not specified Benign:2
Variant summary: APC c.2847G>T (p.Met949Ile) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.8e-05 in 250790 control chromosomes, predominantly at a frequency of 0.00068 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 9.5 fold of the estimated maximal expected allele frequency for a pathogenic variant in APC causing Familial Adenomatous Polyposis phenotype (7.1e-05), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. c.2847G>T has been reported in the literature in at-least two individuals, one stated as affected with non-familial adenomatous polyposis and non MUTYH-associated polyposis (Azzopard_2008) and another with Ependymoma in a sequencing study of 1120 young cancer patients (Zhang_2015). These report(s) do not provide unequivocal conclusions about association of the variant with Familial Adenomatous Polyposis. At-least one co-occurrence with another pathogenic variant has been observed at our laboratory (BRCA2 c.8548_8551delGAAG, p.Glu2850fs), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (benign, n=1; likely benign, n=3; VUS, n=2). Based on the evidence outlined above, the variant was classified as benign.
Colorectal adenoma Uncertain:1
not provided Benign:1
This variant is associated with the following publications: (PMID: 25637381, 21859464, 24055113, 18199528, 26991699)
APC-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at