chr16-2084417-G-C

Variant names:

• chr16-2084417-G-C
• rs45466399
• NM_000548.5:c.4195G>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000548.5(TSC2):​c.4195G>C​(p.Gly1399Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,458,746 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 Uncertain significance (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1399V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.75
• Publications: 12 publications found

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 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
• lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.32802033).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000548.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.4195G>C	p.Gly1399Arg	missense	Exon 34 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.4192G>C	p.Gly1398Arg	missense	Exon 34 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.4126G>C	p.Gly1376Arg	missense	Exon 33 of 41	NP_001107854.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.4195G>C	p.Gly1399Arg	missense	Exon 34 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.4126G>C	p.Gly1376Arg	missense	Exon 33 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.3994G>C	p.Gly1332Arg	missense	Exon 32 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD2 exomes AF: 0.00000409 AC: 1 AN: 244278 AF XY: 0.00000752

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000551

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1458746 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 725580

African (AFR) AF: 0.00 AC: 0 AN: 33426

American (AMR) AF: 0.00 AC: 0 AN: 44598

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26080

East Asian (EAS) AF: 0.0000253 AC: 1 AN: 39592

South Asian (SAS) AF: 0.00 AC: 0 AN: 85880

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51754

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111336

Other (OTH) AF: 0.00 AC: 0 AN: 60314

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Sep 28, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 1399 of the TSC2 protein (p.Gly1399Arg). This variant is present in population databases (no rsID available, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.080	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.52	D
Eigen	Benign	-0.10
Eigen_PC	Benign	-0.20
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Benign	0.33	T
MetaSVM	Benign	-0.39	T
MutationAssessor	Benign	1.6	L
PhyloP100		2.8
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-1.8	N
REVEL	Uncertain	0.44
Sift	Uncertain	0.015	D
Sift4G	Uncertain	0.023	D
Polyphen		0.73	P
Vest4		0.35
MutPred		0.10		Loss of relative solvent accessibility (P = 0.107)
MVP		0.90
ClinPred		0.39	T
GERP RS		2.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.065
gMVP		0.29
Mutation Taster		=97/3	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs45466399; hg19: chr16-2134418;