1-45329311-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001048174.2(MUTYH):c.1561C>T(p.Gln521Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. Q521Q) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: MUTYH NM_001048174.2 stop_gained
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 1.60

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 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. Fraction of 0.00319 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MUTYH	NM_001128425.2	c.1645C>T	p.Gln549Ter	stop_gained	16/16	ENST00000710952.2
MUTYH	NM_001048174.2	c.1561C>T	p.Gln521Ter	stop_gained	16/16	ENST00000456914.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MUTYH	ENST00000710952.2	c.1645C>T	p.Gln549Ter	stop_gained	16/16		NM_001128425.2
MUTYH	ENST00000456914.7	c.1561C>T	p.Gln521Ter	stop_gained	16/16	1	NM_001048174.2	A1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 30, 2022	The p.Q549* variant (also known as c.1645C>T), located in coding exon 16 of the MUTYH gene, results from a C to T substitution at nucleotide position 1645. This changes the amino acid from a glutamine to a stop codon within coding exon 16. This alteration occurs at the 3' terminus of theMUTYH gene, is not expected to trigger nonsense-mediated mRNAdecay, and only impacts the last amino acid of the protein. The exact functional effect of this alteration is unknown. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Dec 13, 2021	This variant changes 1 nucleotide in exon 16 of the MUTYH gene, creating a premature translation stop signal in the last coding exon. This mutant transcript is predicted to escape nonsense-mediated decay and be expressed as a truncated protein, deleting one amino acid. To our knowledge, this variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MUTYH function is a known mechanism of disease (clinicalgenome.org). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Familial adenomatous polyposis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 02, 2021

This variant has not been reported in the literature in individuals with MUTYH-related conditions. ClinVar contains an entry for this variant (Variation ID: 406862). 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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Gln549*) in the MUTYH gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 1 amino acid(s) of the MUTYH protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
Cadd	Pathogenic	34
Dann	Benign	0.96
Eigen	Uncertain	0.41
Eigen_PC	Benign	0.14
FATHMM_MKL	Benign	0.44	N
MutationTaster	Benign	0.75	D;D;D;D;N;N;N;N;N;N;N;N;N;N
Vest4		0.51
GERP RS		2.5

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs765990397; hg19: chr1-45794983;