rs763047420

Positions:

• chr16-2077722-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4 BP6 BS2

The NM_000548.5(TSC2):​c.2962C>T​(p.Arg988Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000616 in 1,460,268 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R988H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 4.95

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 Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.3823319).
• BP6: Variant 16-2077722-C-T is Benign according to our data. Variant chr16-2077722-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 467979.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=3}. Variant chr16-2077722-C-T is described in Lovd as [Benign].
• BS2: High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.2962C>T	p.Arg988Cys	missense_variant	26/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.2962C>T	p.Arg988Cys	missense_variant	26/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000160 AC: 4 AN: 250072 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135596

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.0000467

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1460268 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 726464

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.0000192

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Feb 01, 2024	- -

Tuberous sclerosis syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jul 10, 2023

This missense variant replaces arginine with cysteine at codon 988 of the TSC2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with TSC2-related disorders in the literature. This variant has been identified in 4/250072 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 21, 2019

In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Functional studies demonstrate no damaging effect (TSC2 LOVD); This variant is associated with the following publications: (PMID: 21520333, 26703369, 28492532) -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 05, 2023

The p.R988C variant (also known as c.2962C>T), located in coding exon 25 of the TSC2 gene, results from a C to T substitution at nucleotide position 2962. The arginine at codon 988 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.036	T
BayesDel_noAF	Uncertain	0.040
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.73	D;.;.;.
Eigen	Benign	0.0029
Eigen_PC	Benign	0.12
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.89	D;D;D;D
M_CAP	Uncertain	0.087	D
MetaRNN	Benign	0.38	T;T;T;T
MetaSVM	Uncertain	0.096	D
MutationAssessor	Benign	1.2	L;.;.;L
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.53	T
PROVEAN	Uncertain	-3.4	D;.;.;D
REVEL	Uncertain	0.57
Sift	Uncertain	0.022	D;.;.;D
Sift4G	Uncertain	0.0020	D;.;.;D
Polyphen		0.0090	B;.;.;B
Vest4		0.58
MutPred		0.42		Loss of MoRF binding (P = 0.0027);Loss of MoRF binding (P = 0.0027);Loss of MoRF binding (P = 0.0027);Loss of MoRF binding (P = 0.0027);
MVP		0.93
ClinPred		0.55	D
GERP RS		4.1
Varity_R		0.26
gMVP		0.57

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs763047420; hg19: chr16-2127723;