chr1-45333452-C-A

Position:

• chr1-45333452-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_001048174.2(MUTYH):​c.225G>T​(p.Trp75Cys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W75R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MUTYH NM_001048174.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.06

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_001048174.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MUTYH	NM_001128425.2	c.309G>T	p.Trp103Cys	missense_variant	3/16	ENST00000710952.2
MUTYH	NM_001048174.2	c.225G>T	p.Trp75Cys	missense_variant	3/16	ENST00000456914.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MUTYH	ENST00000710952.2	c.309G>T	p.Trp103Cys	missense_variant	3/16		NM_001128425.2
MUTYH	ENST00000456914.7	c.225G>T	p.Trp75Cys	missense_variant	3/16	1	NM_001048174.2	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial adenomatous polyposis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 20, 2019

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with MUTYH-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces tryptophan with cysteine at codon 103 of the MUTYH protein (p.Trp103Cys). The tryptophan residue is highly conserved and there is a large physicochemical difference between tryptophan and cysteine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.66	.;.;.;.;.;D;.;.;.;D;T;T
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	.;D;.;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.4	.;.;.;.;.;H;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-12	D;D;D;D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D;D;D;D;D;D;D;D
Polyphen		1.0	.;.;.;.;.;D;D;.;D;.;.;.
Vest4		0.91
MutPred		0.86		.;.;.;.;.;.;.;.;Loss of catalytic residue at L101 (P = 0.0025);.;.;.;
MVP		0.98
MPC		0.69
ClinPred		1.0	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs748170941; hg19: chr1-45799124;