1-45334474-C-T
Variant summary
Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_StrongBP6BS1BS2_Supporting
The NM_001128425.2(MUTYH):c.74G>A(p.Gly25Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000441 in 1,614,126 control chromosomes in the GnomAD database, including 7 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict 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. G25A) has been classified as Uncertain significance.
Frequency
Consequence
NM_001128425.2 missense
Scores
Clinical Significance
Conservation
Publications
- familial adenomatous polyposis 2Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P
- colorectal cancerInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
- familial ovarian cancerInheritance: AD, AR Classification: NO_KNOWN Submitted by: ClinGen
- hereditary breast carcinomaInheritance: AD, AR Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Benign. The variant received -10 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| MUTYH | ENST00000710952.2 | c.74G>A | p.Gly25Asp | missense_variant | Exon 2 of 16 | NM_001128425.2 | ENSP00000518552.2 | |||
| MUTYH | ENST00000456914.7 | c.32G>A | p.Gly11Asp | missense_variant | Exon 2 of 16 | 1 | NM_001048174.2 | ENSP00000407590.2 | ||
| ENSG00000288208 | ENST00000671898.1 | n.578G>A | non_coding_transcript_exon_variant | Exon 6 of 21 | ENSP00000499896.1 |
Frequencies
GnomAD3 genomes AF: 0.000578 AC: 88AN: 152140Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.00107 AC: 269AN: 251484 AF XY: 0.00104 show subpopulations
GnomAD4 exome AF: 0.000427 AC: 624AN: 1461868Hom.: 7 Cov.: 31 AF XY: 0.000439 AC XY: 319AN XY: 727234 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000578 AC: 88AN: 152258Hom.: 0 Cov.: 32 AF XY: 0.000779 AC XY: 58AN XY: 74452 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Familial adenomatous polyposis 2 Uncertain:3Benign:3
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.
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.
not provided Uncertain:1Benign:5
Variant summary: The MUTYH c.74G>A (p.Gly25Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. 3/4 in silico tools predict a benign outcome for this variant (SNPsandGO not captured due to low reliability index). This variant was found in the large and broad cohorts of the ExAC project at an allele frequency of 0.001112 (135/121410 chrs tested), predominantly observed in the East Asian subpopulation (0.013; 114/8654 chrs, including 2 homozygotes). This frequency is about 3 times the estimated maximal expected allele frequency of a pathogenic MUTYH variant (0.0045644), suggesting this is likely a benign polymorphism found primarily in the populations of East Asian origin. Most of the published reports indicate that c.74G>A co-occurs in cis with c.53C>T (P18L). Although c.[53C>T; 74G>A] haplotype has been reported to be enriched in sporadic CRC pts compared to controls (Chen, 2008), in functional studies both the complex allele and its compounds were shown to retain complementation ability and were considered to be functionally neutral. In addition, several reported CRC pts carried known pathogenic variants (APC c.3595_3596delAA (p.Lys1199Glufs), MSH6 c.3724_3726del (p.Arg1242del) , that could have explain CRC phenotype in these families (Taki, 2016, Ring, 2012). Lastly, several reputable databases/diagnostic centers classified the variant of interest as VUS/ Benign. Taking together, by applying ACMG rules, the variant was classified as Benign.
MUTYH: BS1, BS2
This variant is associated with the following publications: (PMID: 18422726, 22641385, 22703879, 11295288, 17252231, 30333958, 29879026, 18811933, 16929514, 25820570, 26684191, 26900293, 25980754, 27443514, 26332594, 24728327, 17703316, 27600092, 29330641, 29667044)
not specified Uncertain:1Benign:2Other:1
Variant identified in a genome or exome case(s) and assessed due to predicted null impact of the variant or pathogenic assertions in the literature or databases. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: ExAC: 1.3% (114/8654) East Asian chromosomes; ClinVar: 4 labs classify as VUS
Hereditary cancer-predisposing syndrome Benign:3
This alteration is classified as 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.
Carcinoma of colon Uncertain:1
The p.Gly25Asp variant was identified in the literature in 18 of 896 proband chromosomes (frequency: 0.020) from Asian individuals (Korean, Chinese, Japanese) with adenomatous polyposis or colorectal cancer, and was present in 6 of 944 control chromosomes (frequency: 0.006) (Chen 2008, Kim 2007, Yanaru-Fujisawa 2008, Zhang 2006). In all these studies, the variant was identified in co-occurrence on the same allele as another MUTYH variant, p.Pro18Leu. Two studies suggest that this haplotype variant allele (containing both p.Pro18Leu and p.Gly25Asp variants) increases the risk of gastric cancer, with significantly higher frequencies of the variant haplotype observed in affected cases than in healthy controls (Chen 2008, Zhang 2006). In addition, a functional study by Chen (2008) found that the haplotype variant allele had a partial effect on protein mitochondrial transport as compared to wild type MUTYH protein. This effect, however, was not found when each variant was tested individually, suggesting an additive effect of the combined variants on the mitochondrial targeting sequences domain of the MUTYH protein. The variant was also identified in dbSNP (ID: rs75321043) “With allele of Uncertain significance” with a minor allele frequency of 0.003 (1000 Genomes Project), in HGMD, and in the “InSiGHT Colon Cancer Database”. The p.Gly25 residue is not conserved in mammals and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein. However, 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. Therefore, this variant is classified as a variant of unknown significance (VUS).
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at