chr17-7674225-C-A

Position:

• chr17-7674225-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000546.6(TP53):​c.738G>T​(p.Met246Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,818 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TP53 NM_000546.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 7.91

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a turn (size 5) in uniprot entity P53_HUMAN there are 9 pathogenic changes around while only 0 benign (100%) in NM_000546.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.972

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TP53	NM_000546.6	c.738G>T	p.Met246Ile	missense_variant	7/11	ENST00000269305.9	NP_000537.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TP53	ENST00000269305.9	c.738G>T	p.Met246Ile	missense_variant	7/11	1	NM_000546.6	ENSP00000269305.4

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461818 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727220

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.: 30

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 03, 2024

The p.M246I variant (also known as c.738G>T), located in coding exon 6 of the TP53 gene, results from a G to T substitution at nucleotide position 738. The methionine at codon 246 is replaced by isoleucine, an amino acid with highly similar properties. Studies conducted in human cell lines are equivocal about this variant's ability to suppress cell growth (Kotler E et al. Mol.Cell. 2018 Jul;71:178-190.e8; Giacomelli AO et al. Nat. Genet. 2018 Oct;50:1381-1387). This variant is in the DNA binding domain of the TP53 protein and is reported to have non-functional transactivation in yeast based assays (Kato S et al. Proc. Natl. Acad. Sci. USA. 2003 Jul;100:8424-9). Two other variants at the same codon, p.M246I (c.738G>C) and p.M246I (c.738G>A), have been identified in individuals meeting Chompret criteria (Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Li-Fraumeni syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 11, 2023

This missense change has been observed in individual(s) with Li-Fraumeni syndrome (PMID: 32817165). This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 246 of the TP53 protein (p.Met246Ile). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 968639). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 12826609, 29979965, 30224644) indicates that this missense variant is expected to disrupt TP53 function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.65	D;D;.;.;.;.;T;T;.;D;.;.;.;.;.;.;D;.;.;.;D
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;.;.;.;D;D;.;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Benign	2.0	.;.;.;.;.;.;.;.;.;M;.;M;M;M;.;.;M;.;.;.;.
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.8	D;D;.;.;.;.;.;.;.;D;.;.;D;D;.;.;D;.;.;D;D
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0030	D;D;.;.;.;.;.;.;.;D;.;.;D;D;.;.;D;.;.;D;D
Sift4G	Uncertain	0.011	D;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;.
Polyphen		1.0	D;.;.;.;.;.;.;.;.;D;.;P;B;P;.;.;D;.;.;.;B
Vest4		0.82
MutPred		0.90		Loss of disorder (P = 0.1467);Loss of disorder (P = 0.1467);.;.;.;.;.;.;.;Loss of disorder (P = 0.1467);.;Loss of disorder (P = 0.1467);Loss of disorder (P = 0.1467);Loss of disorder (P = 0.1467);.;.;Loss of disorder (P = 0.1467);.;.;.;.;
MVP		0.93
MPC		0.32
ClinPred		0.99	D
GERP RS		4.6
Varity_R		0.96
gMVP		0.57

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: rs1019340046; hg19: chr17-7577543; COSMIC: COSV53038458; COSMIC: COSV53038458;