chr17-7675103-G-A
Variant summary
Our verdict is Likely benign. The variant received -4 ACMG points: 1P and 5B. BS3_SupportingPM2_SupportingBS2
This summary comes from the ClinGen Evidence Repository: The NM_000546.6: c.509C>T variant in TP53 is a missense variant predicted to cause substitution of threonine by methionine at amino acid 170 (p.Thr170Met). This variant has been observed in 4-7 heterozygous unrelated females from the same data source with no personal history of cancer prior to age 60 years and no personal history of sarcoma at any age (BS2_Moderate; Internal lab contributor). This variant has an allele frequency of 0.00003293 (3/91094 alleles) in the South Asian population in gnomAD v4.1.0 which is lower than the Clingen TP53 VCEP threshold (<0.00004) for PM2_Supporting, and therefore meets this criterion (PM2_Supporting). In vitro assays performed in yeast and/or human cell lines showed partially functional transactivation, and retained growth suppression activity indicating that this variant does not impact protein function (BS3_Supporting; PMIDs: 12826609, 29979965, 30224644). In summary, this variant meets the criteria to be classified as Likely Benign for Li Fraumeni syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen TP53 VCEP: BS2_Moderate, BS3_Supporting, PM2_Supporting. (Bayesian Points: -2; VCEP specifications version 2.1; 2/6/2025) LINK:https://erepo.genome.network/evrepo/ui/classification/CA000246/MONDO:0018875/009
Frequency
Consequence
NM_000546.6 missense
Scores
Clinical Significance
Conservation
Publications
- breast cancerInheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics
- Li-Fraumeni syndromeInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet
- Li-Fraumeni syndrome 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
- adrenocortical carcinoma, hereditaryInheritance: AD Classification: STRONG Submitted by: Ambry Genetics
- sarcomaInheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
- bone marrow failure syndrome 5Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
- colorectal cancerInheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
- choroid plexus carcinomaInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -4 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TP53 | NM_000546.6 | c.509C>T | p.Thr170Met | 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.509C>T | p.Thr170Met | missense_variant | Exon 5 of 11 | 1 | NM_000546.6 | ENSP00000269305.4 |
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152198Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000477 AC: 12AN: 251322 AF XY: 0.0000736 show subpopulations
GnomAD4 exome AF: 0.0000144 AC: 21AN: 1461888Hom.: 0 Cov.: 35 AF XY: 0.0000193 AC XY: 14AN XY: 727246 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152198Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4AN XY: 74356 show subpopulations
ClinVar
Submissions by phenotype
Li-Fraumeni syndrome Uncertain:1Benign:2
This missense variant replaces threonine with methionine at codon 170 of the TP53 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown that this variant displays normal function in yeast transactivation and human growth suppression and cell proliferation studies (PMID: 12826609, 29979965, 30224644). This variant has been reported in individuals affected with rhabdomyosarcoma and breast cancer in the literature (PMID: 22653678, 31081129). This variant has been identified in 13/282706 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
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The NM_000546.6: c.509C>T variant in TP53 is a missense variant predicted to cause substitution of threonine by methionine at amino acid 170 (p.Thr170Met). This variant has been observed in 4-7 heterozygous unrelated females from the same data source with no personal history of cancer prior to age 60 years and no personal history of sarcoma at any age (BS2_Moderate; Internal lab contributor). This variant has an allele frequency of 0.00003293 (3/91094 alleles) in the South Asian population in gnomAD v4.1.0 which is lower than the Clingen TP53 VCEP threshold (<0.00004) for PM2_Supporting, and therefore meets this criterion (PM2_Supporting). In vitro assays performed in yeast and/or human cell lines showed partially functional transactivation, and retained growth suppression activity indicating that this variant does not impact protein function (BS3_Supporting; PMIDs: 12826609, 29979965, 30224644). In summary, this variant meets the criteria to be classified as Likely Benign for Li Fraumeni syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen TP53 VCEP: BS2_Moderate, BS3_Supporting, PM2_Supporting. (Bayesian Points: -2; VCEP specifications version 2.1; 2/6/2025) -
Li-Fraumeni syndrome 1 Uncertain:2
This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
Hereditary cancer-predisposing syndrome Uncertain:1Benign:1
The p.T170M variant (also known as c.509C>T), located in coding exon 4 of the TP53 gene, results from a C to T substitution at nucleotide position 509. The threonine at codon 170 is replaced by methionine, an amino acid with similar properties. This alteration has been reported in a patient diagnosed with an embryonal rhabdomyosarcoma of the testes at age 5; however, the family history did not resemble Li-Fraumeni syndrome and the parents were unavailable for testing (Magnusson, S et al. Pediatr Blood Cancer. 2012 Nov;59(5):846-53). This alteration was also seen in a penile carcinoma genome and IHC results on the tumor were consistent with altered p53 protein (Rocha, RM et al. Hum Pathol. 2012 Apr;43(4):481-8). This alteration has also been reported in hereditary breast cancer and prostate cancer cohorts (Kharaziha P et al. Clin Genet, 2019 09;96:216-225; Rantapero T et al. Genes (Basel), 2020 03;11:) This variant is in the DNA binding domain of the p53 protein and is reported to have partially functional transactivation capacity and is predicted to affect several p53 isoforms (IARC TP53 database; Kato S et al. Proc Natl Acad Sci USA. 2003 Jul 8;100(14):8424-9). Studies conducted in human cell lines indicate this alteration is proficient at growth suppression and has no dominant negative effect (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 well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
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not provided Uncertain:1
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Published functional studies suggest no damaging effect: intact growth suppression activity and partially functional transactivation (Kotler 2018, Kato 2003); Observed in individuals with breast cancer and rhabdomyosarcoma (Kharaziha 2019, Magnusson 2012); This variant is associated with the following publications: (PMID: 26001389, 29079180, 12826609, 15510160, 22653678, 16546179, 21925707, 25480502, 27311873, 29979965, 28861920, 31016814, 30840781, 14559903, 31081129) -
not specified Benign:1
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TP53-related disorder Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at