Genetic Variant TPMT:p.Ala167Gly (chr6-18133884-G-C) – 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_000367.5(TPMT):c.500C>G(p.Ala167Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000745 in 1,611,232 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 drug response (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A167T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000069 ( 0 hom. )

Consequence

TPMT
NM_000367.5 missense

Scores

Clinical Significance

drug response no assertion criteria provided O:1

Conservation

PhyloP100: 0.715

Publications

13 publications found

Variant links:

Genes affected

TPMT (HGNC:12014): (thiopurine S-methyltransferase) This gene encodes the enzyme that metabolizes thiopurine drugs via S-adenosyl-L-methionine as the S-methyl donor and S-adenosyl-L-homocysteine as a byproduct. Thiopurine drugs such as 6-mercaptopurine are used as chemotherapeutic agents. Genetic polymorphisms that affect this enzymatic activity are correlated with variations in sensitivity and toxicity to such drugs within individuals, causing thiopurine S-methyltransferase deficiency. Related pseudogenes have been identified on chromosomes 3, 18 and X. [provided by RefSeq, Aug 2014]

TPMT links:

ENSG00000307971 (HGNC:):

ENSG00000307971 links:

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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

MetaRNN computational evidence supports a deleterious effect, 0.991

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPMT	NM_000367.5 link	c.500C>G	p.Ala167Gly	missense_variant	Exon 7 of 9	ENST00000309983.5	NP_000358.1	P51580A0A024QZW0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPMT	ENST00000309983.5 link	c.500C>G	p.Ala167Gly	missense_variant	Exon 7 of 9	1	NM_000367.5	ENSP00000312304.4		P51580
ENSG00000307971	ENST00000830125.1 link	n.267+10778G>C		intron_variant	Intron 1 of 2

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152058

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251372

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

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:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000685

AC:

AN:

1459174

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726094

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33442

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26116

East Asian (EAS)

AF:

0.00

AC:

AN:

39666

South Asian (SAS)

AF:

0.00

AC:

AN:

86190

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53402

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.00000811

AC:

AN:

1109568

Other (OTH)

AF:

0.0000166

AC:

AN:

60316

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152058

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74244

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41402

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10548

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.350

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000821

Hom.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: drug response

Submissions summary: Other:1

Revision: no assertion criteria provided

LINK: link

Submissions by phenotype

Thiopurine S-methyltransferase deficiency

Other:1

Oct 01, 2007

OMIM

Significance:drug response

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Uncertain

-0.050

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.53

Eigen

Benign

-0.48

Eigen_PC

Benign

-0.69

FATHMM_MKL

Benign

0.22

LIST_S2

Benign

0.57

M_CAP

Benign

0.042

MetaRNN

Pathogenic

0.99

MetaSVM

Benign

-0.74

MutationAssessor

Pathogenic

3.3

PhyloP100

0.71

PrimateAI

Benign

0.26

PROVEAN

Uncertain

-2.7

REVEL

Uncertain

0.34

Sift

Uncertain

0.019

Sift4G

Uncertain

0.0050

Polyphen

0.55

Vest4

0.77

MutPred

0.92

Loss of stability (P = 0.0868);

MVP

0.68

MPC

0.20

ClinPred

0.65

GERP RS

0.097

Varity_R

0.53

gMVP

0.66

Mutation Taster

=39/61

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

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

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6-18133884-G-C

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over