Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate
The NM_001128425.2(MUTYH):c.289C>G(p.Arg97Gly) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R97Q) has been classified as Uncertain significance.
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: Likely_pathogenic. The variant received 6 ACMG points.
PM1
In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 18 benign, 56 uncertain in NM_001128425.2
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.863
The p.R97G variant (also known as c.289C>G), located in coding exon 3 of the MUTYH gene, results from a C to G substitution at nucleotide position 289. The arginine at codon 97 is replaced by glycine, an amino acid with dissimilar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -