rs1553123017

Variant names:

• chr1-45329405-G-GCA
• rs1553123017
• NM_001128425.2:c.1549_1550dupTG

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_001128425.2(MUTYH):​c.1549_1550dupTG​(p.Ser518AlafsTer54) 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 Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. C517C) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MUTYH NM_001128425.2 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 1.14
• Publications: 0 publications found

Genes affected

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

ENSG00000288208 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 14 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-45329405-G-GCA is Pathogenic according to our data. Variant chr1-45329405-G-GCA is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 406826.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001128425.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MUTYH	NM_001128425.2	MANE Plus Clinical	c.1549_1550dupTG	p.Ser518AlafsTer54	frameshift	Exon 16 of 16	NP_001121897.1
	MUTYH	NM_001048174.2	MANE Select	c.1465_1466dupTG	p.Ser490AlafsTer54	frameshift	Exon 16 of 16	NP_001041639.1
	MUTYH	NM_012222.3		c.1540_1541dupTG	p.Ser515AlafsTer54	frameshift	Exon 16 of 16	NP_036354.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MUTYH	ENST00000710952.2	MANE Plus Clinical	c.1549_1550dupTG	p.Ser518AlafsTer54	frameshift	Exon 16 of 16	ENSP00000518552.2
	MUTYH	ENST00000456914.7	TSL:1 MANE Select	c.1465_1466dupTG	p.Ser490AlafsTer54	frameshift	Exon 16 of 16	ENSP00000407590.2
	MUTYH	ENST00000372098.7	TSL:1	c.1540_1541dupTG	p.Ser515AlafsTer54	frameshift	Exon 16 of 16	ENSP00000361170.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial adenomatous polyposis 2 Pathogenic:1

Oct 18, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change results in a premature translational stop signal in the MUTYH gene (p.Ser518Alafs*54). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 32 amino acids of the MUTYH protein. This variant is not present in population databases (ExAC no frequency). This frameshift disrupts the conserved PCNA binding motif of MUTYH (Gln526-Phe533, also known as Gln512-Phe519 in the literature because of transcript nomenclature differences), which has been shown to be critical for MUTYH-PCNA binding (PMID: 11092888, 26377631). Experimental studies have shown that MUTYH and PCNA co-localize at sites of DNA replication, and that MUTYH-PCNA complexes possess adenine glycosylase activity (PMID: 11433026). In MUTYH-deficient murine cells, a mutated MUTYH protein in which the conserved PCNA binding motif was disrupted did not increase repair efficiency as compared to wild-type MUTYH (PMID: 11864576). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant has not been reported in the literature in individuals with MUTYH-related disease. ClinVar contains an entry for this variant (Variation ID: 406826).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.1

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1553123017; hg19: chr1-45795077;