17-7675174-C-A

Variant names:

• chr17-7675174-C-A
• rs1131691026
• NM_000546.6:c.438G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000546.6(TP53):​c.438G>T​(p.Trp146Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W146G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TP53 NM_000546.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 1.24
• Publications: 84 publications found

Genes affected

TP53 (HGNC:11998): (tumor protein p53) This gene encodes a tumor suppressor protein containing transcriptional activation, DNA binding, and oligomerization domains. The encoded protein responds to diverse cellular stresses to regulate expression of target genes, thereby inducing cell cycle arrest, apoptosis, senescence, DNA repair, or changes in metabolism. Mutations in this gene are associated with a variety of human cancers, including hereditary cancers such as Li-Fraumeni syndrome. Alternative splicing of this gene and the use of alternate promoters result in multiple transcript variants and isoforms. Additional isoforms have also been shown to result from the use of alternate translation initiation codons from identical transcript variants (PMIDs: 12032546, 20937277). [provided by RefSeq, Dec 2016]

TP53 Gene-Disease associations (from GenCC):

• breast cancer

  Inheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics
• Li-Fraumeni syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet
• Li-Fraumeni syndrome 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
• adrenocortical carcinoma, hereditary

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• sarcoma

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• bone marrow failure syndrome 5

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• colorectal cancer

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• choroid plexus carcinoma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 27 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 50 uncertain in NM_000546.6
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TP53	NM_000546.6	c.438G>T	p.Trp146Cys	missense_variant	Exon 5 of 11	ENST00000269305.9	NP_000537.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TP53	ENST00000269305.9	c.438G>T	p.Trp146Cys	missense_variant	Exon 5 of 11	1	NM_000546.6	ENSP00000269305.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

May 13, 2019

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.W146C variant (also known as c.438G>T), located in coding exon 4 of the TP53 gene, results from a G to T substitution at nucleotide position 438. The tryptophan at codon 146 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant is in the DNA binding domain of the TP53 protein and is reported to have partial loss of transactivation in yeast based assays (IARC TP53 database: Kato S et al. Proc. Natl. Acad. Sci. USA 2003 Jul;100:8424-9). Studies conducted in human cell lines indicate this alteration remains proficient at growth suppression (Kotler E et al. Mol.Cell. 2018 Jul;71:178-190.e8; Giacomelli AO et al. Nat. Genet. 2018 Oct;50:1381-1387). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Jun 18, 2022

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Li-Fraumeni syndrome 1 Uncertain:1

Jun 18, 2022

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Li-Fraumeni syndrome Uncertain:1

Aug 27, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TP53 protein function. This variant has not been reported in the literature in individuals with TP53-related conditions. ClinVar contains an entry for this variant (Variation ID: 824855). This variant is not present in population databases (ExAC no frequency). This sequence change replaces tryptophan with cysteine at codon 146 of the TP53 protein (p.Trp146Cys). The tryptophan residue is moderately 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	0.63
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.64	D;D;.;.;.;.;D;.;.;.;.;.;.;D;.;.;.;D;D;D
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.077
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;.;.;.;D;D;.;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Uncertain	0.67	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	.;.;.;.;.;.;M;.;M;M;M;.;.;M;.;.;.;.;.;.
PhyloP100		1.2
PrimateAI	Benign	0.48	T
PROVEAN	Benign	-1.7	N;N;.;.;.;.;N;.;.;N;N;.;.;N;.;.;N;D;D;.
REVEL	Uncertain	0.63
Sift	Uncertain	0.021	D;D;.;.;.;.;D;.;.;D;D;.;.;D;.;.;D;D;D;.
Sift4G	Uncertain	0.039	D;D;T;T;T;T;D;T;D;D;D;T;T;D;T;D;T;.;.;T
Polyphen		1.0	D;.;.;.;.;.;D;.;D;D;D;.;.;D;.;.;.;P;.;.
Vest4		0.46
MutPred		0.58		Gain of disorder (P = 0.0316);Gain of disorder (P = 0.0316);.;.;.;.;Gain of disorder (P = 0.0316);.;Gain of disorder (P = 0.0316);Gain of disorder (P = 0.0316);Gain of disorder (P = 0.0316);.;.;Gain of disorder (P = 0.0316);.;.;.;.;Gain of disorder (P = 0.0316);.;
MVP		0.96
MPC		2.1
ClinPred		0.88	D
GERP RS		4.5
PromoterAI		0.027	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.77
gMVP		0.58

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

Other links and lift over

dbSNP: rs1131691026; hg19: chr17-7578492; COSMIC: COSV52987374;