6-18130716-C-G

Position:

• chr6-18130716-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000367.5(TPMT):​c.690G>C​(p.Trp230Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,010 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TPMT NM_000367.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.12

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TPMT	NM_000367.5	c.690G>C	p.Trp230Cys	missense_variant	9/9	ENST00000309983.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TPMT	ENST00000309983.5	c.690G>C	p.Trp230Cys	missense_variant	9/9	1	NM_000367.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461010 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726836

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 01, 2023

The c.690G>C (p.W230C) alteration is located in exon 9 (coding exon 8) of the TPMT gene. This alteration results from a G to C substitution at nucleotide position 690, causing the tryptophan (W) at amino acid position 230 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.68	D
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.065	D
MetaRNN	Uncertain	0.61	D
MetaSVM	Uncertain	0.12	D
MutationAssessor	Uncertain	2.7	M
MutationTaster	Benign	1.0	D
PrimateAI	Benign	0.47	T
PROVEAN	Pathogenic	-4.9	D
REVEL	Uncertain	0.63
Sift	Uncertain	0.0070	D
Sift4G	Benign	0.095	T
Polyphen		1.0	D
Vest4		0.42
MutPred		0.60		Gain of methylation at K228 (P = 0.0778);
MVP		0.87
MPC		0.73
ClinPred		0.99	D
GERP RS		5.9
Varity_R		0.88
gMVP		0.87

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr6-18130947;