chr16-2060709-G-C

Variant names:

• chr16-2060709-G-C
• rs559727962
• NM_000548.5:c.1015G>C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000548.5(TSC2):​c.1015G>C​(p.Val339Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V339I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.77

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 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 15 uncertain in NM_000548.5
• 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.1015G>C	p.Val339Leu	missense_variant	Exon 11 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1015G>C	p.Val339Leu	missense_variant	Exon 11 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Feb 12, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine with leucine at codon 339 of the TSC2 protein (p.Val339Leu). The valine residue is highly conserved and there is a small physicochemical difference between valine and leucine. 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: "Deleterious"; 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). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.50	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Uncertain	0.61	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.20	T
MutationAssessor	Uncertain	2.3	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-1.9	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.43
Sift	Uncertain	0.019	D;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Uncertain	0.033	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.99	D;.;.;.;D;D;.;.;D;P;.;.;.;.;.
Vest4		0.82
MutPred		0.42		Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;
MVP		0.67
ClinPred		0.93	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.52
gMVP		0.63

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.20		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.20		Position offset: 17

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs559727962; hg19: chr16-2110710;