Genetic Variant MTAP:p.Lys40Met (chr9-21815518-A-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_002451.4(MTAP):c.119A>T(p.Lys40Met) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 151,864 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K40R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Consequence

MTAP
NM_002451.4 missense, splice_region

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 8.33

Publications

1 publications found

Variant links:

Genes affected

MTAP (HGNC:7413): (methylthioadenosine phosphorylase) This gene encodes an enzyme that plays a major role in polyamine metabolism and is important for the salvage pathway of both adenine and methionine. The encoded enzyme is deficient in many cancers. Multiple alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Sep 2021]

MTAP Gene-Disease associations (from GenCC):

diaphyseal medullary stenosis-bone malignancy syndrome
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Genomics England PanelApp, G2P, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen

MTAP links:

ENSG00000264545 (HGNC:):

ENSG00000264545 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTAP	NM_002451.4 link	c.119A>T	p.Lys40Met	missense_variant, splice_region_variant	Exon 2 of 8	ENST00000644715.2	NP_002442.2	Q13126-1A0A384ME80

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTAP	ENST00000644715.2 link	c.119A>T	p.Lys40Met	missense_variant, splice_region_variant	Exon 2 of 8		NM_002451.4	ENSP00000494373.1		Q13126-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151864

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000400

AC:

AN:

250170

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000617

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151864

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74166

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41330

American (AMR)

AF:

0.00

AC:

AN:

15250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10512

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67974

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.26

BayesDel_addAF

Uncertain

0.14

BayesDel_noAF

Pathogenic

0.15

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.83

D;D;D;.

Eigen

Pathogenic

0.70

Eigen_PC

Pathogenic

0.70

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

.;D;D;D

M_CAP

Uncertain

0.22

MetaRNN

Pathogenic

0.80

D;D;D;D

MetaSVM

Uncertain

0.64

MutationAssessor

Uncertain

2.3

M;.;M;M

PhyloP100

8.3

PrimateAI

Pathogenic

0.82

PROVEAN

Uncertain

-4.3

D;.;.;.

REVEL

Pathogenic

0.83

Sift

Uncertain

0.020

D;.;.;.

Sift4G

Uncertain

0.031

D;D;.;D

Polyphen

0.91

P;P;P;.

Vest4

0.83

MutPred

0.44

.;Loss of methylation at K57 (P = 0.0057);.;.;

MVP

0.96

MPC

0.61

ClinPred

0.98

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.78

gMVP

0.86

Mutation Taster

=3/97

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

1.0

SpliceAI score (max)

0.18

Details are displayed if max score is > 0.2

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

Publications

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9-21815518-A-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over