rs1555499648

chr16-2058760-G-Achr16-2058760-G-Cchr16-2058760-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000548.5(TSC2):c.862G>A(p.Asp288Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. D288E) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.51

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 5 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 16 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.806

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.862G>A	p.Asp288Asn	missense_variant	10/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.862G>A	p.Asp288Asn	missense_variant	10/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 18, 2017

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 C15"). 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 aspartic acid with asparagine at codon 288 of the TSC2 protein (p.Asp288Asn). The aspartic acid residue is highly conserved and there is a small physicochemical difference between aspartic acid and asparagine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 26, 2022

The p.D288N variant (also known as c.862G>A), located in coding exon 9 of the TSC2 gene, results from a G to A substitution at nucleotide position 862. The aspartic acid at codon 288 is replaced by asparagine, an amino acid with highly similar properties. This amino acid position is highly 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	Uncertain	0.51
BayesDel_addAF	Uncertain	0.089	D
BayesDel_noAF	Benign	-0.11
Cadd	Uncertain	25
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.81	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.062	T
MutationAssessor	Uncertain	2.1	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-3.9	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.45
Sift	Benign	0.078	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Pathogenic	0.0	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		1.0	D;.;.;.;D;D;.;.;D;D;.;.;.;.;.
Vest4		0.85
MutPred		0.59		Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);.;Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);.;Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);Gain of catalytic residue at D288 (P = 0.0446);.;
MVP		0.91
ClinPred		0.98	D
GERP RS		5.1
Varity_R		0.43
gMVP		0.63

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: rs1555499648; hg19: chr16-2108761;