Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_001048174.2(MUTYH):c.725delTinsAG(p.Val242fs) variant causes a frameshift, missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V242E) has been classified as Uncertain significance. Variant results in nonsense mediated mRNA decay.
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]
Verdict is Pathogenic. Variant got 12 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 1-45332290-A-CT is Pathogenic according to our data. Variant chr1-45332290-A-CT is described in ClinVar as [Pathogenic]. Clinvar id is 533305.Status of the report is criteria_provided_single_submitter, 1 stars.
The c.809delTinsAG pathogenic mutation, located in coding exon 10 of the MUTYH gene, results from the deletion of one nucleotide and insertion of two nucleotides causing a translational frameshift with a predicted alternate stop codon (p.V270Efs*59). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -