Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1PM2PM5PP3_StrongPP5_Moderate
The NM_001048174.2(MUTYH):c.253T>G(p.Trp85Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W85R) has been classified as Likely pathogenic.
MUTYH (HGNC:7527): (mutY DNA glycosylase) This gene encodes a DNA glycosylase involved in oxidative DNA damage repair. The enzyme excises adenine bases from the DNA backbone at sites where adenine is inappropriately paired with guanine, cytosine, or 8-oxo-7,8-dihydroguanine, a major oxidatively damaged DNA lesion. The protein is localized to the nucleus and mitochondria. This gene product is thought to play a role in signaling apoptosis by the introduction of single-strand breaks following oxidative damage. Mutations in this gene result in heritable predisposition to colorectal cancer, termed MUTYH-associated polyposis (MAP). Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2017]
MUTYH Gene-Disease associations (from GenCC):
familial adenomatous polyposis 2
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P
colorectal cancer
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
familial ovarian cancer
Inheritance: AD, AR Classification: NO_KNOWN Submitted by: ClinGen
hereditary breast carcinoma
Inheritance: AD, AR Classification: NO_KNOWN Submitted by: ClinGen
Our verdict: Pathogenic. The variant received 12 ACMG points.
PM1
In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 18 benign, 62 uncertain in NM_001048174.2
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-45333424-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 533303.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.982
PP5
Variant 1-45333424-A-C is Pathogenic according to our data. Variant chr1-45333424-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3233037.Status of the report is criteria_provided_single_submitter, 1 stars.
The p.W113G variant (also known as c.337T>G), located in coding exon 3 of the MUTYH gene, results from a T to G substitution at nucleotide position 337. The tryptophan at codon 113 is replaced by glycine, an amino acid with highly dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -