16-2071860-G-C

Variant summary

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

The NM_000548.5(TSC2):c.2023G>C(p.Ala675Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/20 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. A675S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.145

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.15542239).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.2023G>C	p.Ala675Pro	missense_variant	19/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.2023G>C	p.Ala675Pro	missense_variant	19/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1384036 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 681978

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 16, 2024

This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 675 of the TSC2 protein (p.Ala675Pro). 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.079
BayesDel_addAF	Benign	-0.011	T
BayesDel_noAF	Benign	-0.25
Cadd	Benign	0.11
Dann	Benign	0.75
DEOGEN2	Uncertain	0.51	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.78	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
M_CAP	Uncertain	0.086	D
MetaRNN	Benign	0.16	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.78	T
MutationAssessor	Benign	0.0	N;.;.;.;N;N;.;.;.;N;.;N;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.2	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.41
Sift	Benign	0.28	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.18	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.30	B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.22
MutPred		0.56		Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);.;Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);.;Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);Gain of glycosylation at A675 (P = 0.0062);.;
MVP		0.88
ClinPred		0.032	T
GERP RS		-4.5
Varity_R		0.11
gMVP		0.42

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: rs764840082; hg19: chr16-2121861;