16-2061884-C-G

Position:

• chr16-2061884-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000548.5(TSC2):​c.1133C>G​(p.Pro378Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. 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. P378L) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 2.33

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]

TSC2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2550673).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.1133C>G	p.Pro378Arg	missense_variant	12/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1133C>G	p.Pro378Arg	missense_variant	12/42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461832 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727214

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 05, 2024	This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 378 of the TSC2 protein (p.Pro378Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 237959). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TSC2 protein function with a negative predictive value of 95%. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jan 03, 2024	In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 18466115) -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Apr 15, 2022	PM2 -

Lymphangiomyomatosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Nov 15, 2018

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Lymphangiomyomatosis;C1846385:Isolated focal cortical dysplasia type II;C1860707:Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 13, 2024

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 02, 2022

The p.P378R variant (also known as c.1133C>G), located in coding exon 11 of the TSC2 gene, results from a C to G substitution at nucleotide position 1133. The proline at codon 378 is replaced by arginine, an amino acid with dissimilar properties. This amino acid position is not 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	0.099
BayesDel_addAF	Uncertain	0.069	D
BayesDel_noAF	Benign	-0.14
CADD	Benign	18
DANN	Benign	0.95
DEOGEN2	Uncertain	0.65	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.44
Eigen_PC	Benign	-0.39
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.95	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.37	D
MetaRNN	Benign	0.26	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.32	T
MutationAssessor	Benign	0.69	N;.;.;.;N;N;.;.;.;N;.;N;.;.;.
PrimateAI	Benign	0.33	T
PROVEAN	Uncertain	-3.6	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.42
Sift	Uncertain	0.013	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Benign	0.34	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.26	B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.48
MutPred		0.33		Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);.;Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);.;Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);.;
MVP		0.86
ClinPred		0.31	T
GERP RS		2.0
Varity_R		0.21
gMVP		0.20

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: rs45517154; hg19: chr16-2111885;