Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2BP4_StrongBP6BP7
The NM_001048174.2(MUTYH):āc.849A>Gā(p.Arg283Arg) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,176 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
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 Likely_benign. Variant got -4 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.53).
BP6
Variant 1-45332166-T-C is Benign according to our data. Variant chr1-45332166-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 936532.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
BP7
Synonymous conserved (PhyloP=1.85 with no splicing effect.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is considered likely benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -
Aug 16, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MUTYH-related conditions. ClinVar contains an entry for this variant (Variation ID: 936532). This sequence change affects codon 311 of the MUTYH mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MUTYH protein. It affects a nucleotide within the consensus splice site. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.933A>G variant (also known as p.R311R), located in coding exon 10 of the MUTYH gene, results from an A to G substitution at nucleotide position 933. This nucleotide substitution does not change the arginine at codon 311. However, this change occurs in the last base pair of coding exon 10, which makes it likely to have some effect on normal mRNA splicing. This nucleotide position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. Based on the available evidence, the clinical significance of this variant remains unclear. -