16-2084522-G-T

Variant names:

• chr16-2084522-G-T
• rs1555514295
• NM_000548.5:c.4300G>T

Variant summary

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

The NM_000548.5(TSC2):​c.4300G>T​(p.Gly1434Cys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. G1434G) has been classified as Benign.

• Frequency: Genomes: not found (cov: 34)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.69

Genes affected

TSC2 (HGNC:12363): (TSC complex subunit 2) This gene is a tumor suppressor gene that encodes the growth inhibitory protein tuberin. Tuberin interacts with hamartin to form the TSC protein complex which functions in the control of cell growth. This TSC protein complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]

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 rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.4300G>T	p.Gly1434Cys	missense_variant	Exon 34 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.4300G>T	p.Gly1434Cys	missense_variant	Exon 34 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Nov 03, 2018

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with TSC2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with cysteine at codon 1434 of the TSC2 protein (p.Gly1434Cys). The glycine residue is moderately conserved and there is a large physicochemical difference between glycine and cysteine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Dec 07, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G1434C variant (also known as c.4300G>T), located in coding exon 33 of the TSC2 gene, results from a G to T substitution at nucleotide position 4300. The glycine at codon 1434 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is conserved. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.23
Eigen_PC	Benign	0.16
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.23	D
MetaRNN	Uncertain	0.59	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.035	D
MutationAssessor	Uncertain	2.0	M;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.53	T
PROVEAN	Uncertain	-3.1	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.43
Sift	Uncertain	0.019	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.018	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		1.0	D;.;.;.;D;D;.;.;D;D;.;.;.;.;.
Vest4		0.67
MutPred		0.27		Loss of relative solvent accessibility (P = 0.0071);.;.;.;.;.;.;Loss of relative solvent accessibility (P = 0.0071);.;.;.;.;.;.;.;
MVP		0.94
ClinPred		0.91	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.22
gMVP		0.59

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: rs1555514295; hg19: chr16-2134523;