Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_001048174.2(MUTYH):c.60delA(p.Arg22GlyfsTer41) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as 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]
Verdict is Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 291 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 1-45334445-CT-C is Pathogenic according to our data. Variant chr1-45334445-CT-C is described in ClinVar as [Pathogenic]. Clinvar id is 406847.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 406847). This variant has not been reported in the literature in individuals affected with MUTYH-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Arg36Glyfs*22) in the MUTYH gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MUTYH are known to be pathogenic (PMID: 18534194, 20663686). -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.102delA pathogenic mutation, located in coding exon 2 of the MUTYH gene, results from a deletion of one nucleotide at nucleotide position 102, causing a translational frameshift with a predicted alternate stop codon (p.R36Gfs*22). 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. -