1-45331316-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001048174.2(MUTYH):c.1258C>G(p.His420Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,890 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H420N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MUTYH NM_001048174.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:3
• Conservation: PhyloP100: 9.21

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 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.954

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MUTYH	NM_001128425.2	c.1342C>G	p.His448Asp	missense_variant	14/16	ENST00000710952.2
MUTYH	NM_001048174.2	c.1258C>G	p.His420Asp	missense_variant	14/16	ENST00000456914.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MUTYH	ENST00000710952.2	c.1342C>G	p.His448Asp	missense_variant	14/16		NM_001128425.2
MUTYH	ENST00000456914.7	c.1258C>G	p.His420Asp	missense_variant	14/16	1	NM_001048174.2	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461890 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial adenomatous polyposis 2 Pathogenic:1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Aug 06, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Sep 01, 2023	This sequence change replaces histidine, which is basic and polar, with aspartic acid, which is acidic and polar, at codon 448 of the MUTYH protein (p.His448Asp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with primary sclerosing cholangitis (PMID: 19443904). ClinVar contains an entry for this variant (Variation ID: 185383). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on MUTYH function (PMID: 19443904). 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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 28, 2022

The p.H448D variant (also known as c.1342C>G), located in coding exon 14 of the MUTYH gene, results from a C to G substitution at nucleotide position 1342. The histidine at codon 448 is replaced by aspartic acid, an amino acid with similar properties. Functional analyses of this alteration showed decreased/impaired DNA glycosylase activity compared to wild type MUTYH (Forsbring M, Carcinogenesis 2009 Jul; 30(7):1147-54). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
Cadd	Pathogenic	28
Dann	Uncertain	0.99
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-8.3	D;D;D;D;D;D;D;D;D;D;D;.
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;D;.
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;D;D
Polyphen		0.99, 1.0, 1.0	.;.;.;.;.;.;D;D;.;.;D;.
Vest4		0.93
MutPred		0.78		.;.;.;.;.;.;.;.;.;.;Gain of catalytic residue at H448 (P = 0.0466);.;
MVP		1.0
MPC		0.64
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.98
gMVP		0.88

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: rs786202133; hg19: chr1-45796988; COSMIC: COSV58344509; COSMIC: COSV58344509;