NM_000548.5:c.1433A>G

Variant names:

• chr16-2063043-A-G
• rs1555501733
• NM_000548.5:c.1433A>G

Variant summary

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

The NM_000548.5(TSC2):​c.1433A>G​(p.Gln478Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000715 in 1,399,218 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 8.55

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.1433A>G	p.Gln478Arg	missense_variant	Exon 14 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1433A>G	p.Gln478Arg	missense_variant	Exon 14 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.15e-7 AC: 1 AN: 1399218 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 690126

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: 9.27e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Dec 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 478 of the TSC2 protein (p.Gln478Arg). 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: 467871). 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. -

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Feb 21, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 20, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Q478R variant (also known as c.1433A>G), located in coding exon 13 of the TSC2 gene, results from an A to G substitution at nucleotide position 1433. The glutamine at codon 478 is replaced by arginine, 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	Pathogenic	0.58
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.50	T;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.83	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
M_CAP	Uncertain	0.12	D
MetaRNN	Uncertain	0.63	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-0.46	T
MutationAssessor	Benign	1.9	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-1.3	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.42
Sift	Benign	0.079	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.073	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.95	P;.;.;.;D;D;.;.;D;P;.;.;.;.;.
Vest4		0.76
MutPred		0.41		Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);.;Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);.;Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);.;
MVP		0.87
ClinPred		0.80	D
GERP RS		5.0
Varity_R		0.43
gMVP		0.53

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1555501733; hg19: chr16-2113044;