16-2070517-A-G

Position:

• chr16-2070517-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PM5 PP3_Moderate

The NM_000548.5(TSC2):​c.1778A>G​(p.His593Arg) 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H593L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:3 O:1
• Conservation: PhyloP100: 9.25

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-2070517-A-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.853

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.1778A>G	p.His593Arg	missense_variant	17/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1778A>G	p.His593Arg	missense_variant	17/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:3 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Division of Genomic Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University	Jul 19, 2022	According to ACMG GL 2015, this variant located in Hamartin binding domain (PM1), absent from controls (PM2), multiple lines of computational evidence support a deleterious effect (PP3). Also detected in the patient with clinically definitive tuberous sclerosis complex (PP4), and cosegregation with disease in multiple affected family members (PP1). -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 08, 2022	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. 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. ClinVar contains an entry for this variant (Variation ID: 49173). This missense change has been observed in individual(s) with tuberous sclerosis complex (PMID: 10735580). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces histidine, which is basic and polar, with arginine, which is basic and polar, at codon 593 of the TSC2 protein (p.His593Arg). -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Mar 29, 2021

Reported previously as a possible polymorphism in a patient with a clinical diagnosis of TSC; however, no additional information was provided to unequivocally demonstrate that it is benign (Choy et al., 1999); Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 10735580, 17304050) -

Tuberous sclerosis syndrome Other:1

not provided, no classification provided

curation

Tuberous sclerosis database (TSC2)

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- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.47
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.86	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.16	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.22	T
MutationAssessor	Uncertain	2.7	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-5.8	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.53
Sift	Uncertain	0.0060	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.0060	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.99	D;.;.;.;D;D;.;.;D;D;.;.;.;.;.
Vest4		0.94
MutPred		0.30		Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);.;Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);.;Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);.;
MVP		0.93
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.79
gMVP		0.86

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: rs45517198; hg19: chr16-2120518; COSMIC: COSV54755130; COSMIC: COSV54755130;