Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_001048174.2(MUTYH):c.337delC(p.Gln113ArgfsTer5) variant causes a frameshift 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 (★★). 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 18 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 1-45333137-TG-T is Pathogenic according to our data. Variant chr1-45333137-TG-T is described in ClinVar as [Pathogenic]. Clinvar id is 464719.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-45333137-TG-T is described in Lovd as [Likely_pathogenic]. Variant chr1-45333137-TG-T is described in Lovd as [Pathogenic].
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change deletes 1 nucleotide in exon 5 of the MUTYH mRNA (c.421delC), causing a frameshift at codon 141. This creates a premature translational stop signal (p.Gln141Argfs*5) and is expected to result in an absent or disrupted protein product. Loss-of-function variants in MUTYH are known to be pathogenic. This particular variant has been reported as compound heterozygous with other pathogenic variants in MUTYH in individuals with Muir–Torre syndrome (PMID: 16207212), attenuated polyposis (PMID: 22865608), and colorectal adenomas (PMID: 22773231). This variant is also known as 379delC. For these reasons, this variant has been classified as Pathogenic. -
Jul 02, 2018
Mendelics
Significance: Pathogenic
Review Status: criteria provided, single submitter