16-2083773-A-T

Position:

• chr16-2083773-A-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4 BP6 BS2

The NM_000548.5(TSC2):​c.3962A>T​(p.Glu1321Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,458,868 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E1321D) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:2 O:1
• Conservation: PhyloP100: 1.49

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_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.3953495).
• BP6: Variant 16-2083773-A-T is Benign according to our data. Variant chr16-2083773-A-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 135383.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=5, Benign=1, not_provided=1, Likely_benign=1}.
• BS2: High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.3962A>T	p.Glu1321Val	missense_variant	33/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.3962A>T	p.Glu1321Val	missense_variant	33/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000408 AC: 1 AN: 244910 Hom.: 0 AF XY: 0.00000753 AC XY: 1 AN XY: 132860

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000904

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1458868 Hom.: 0 Cov.: 32 AF XY: 0.00000689 AC XY: 5 AN XY: 725516

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: 0.0000117

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000829 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:2 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2 Benign:1

Benign, criteria provided, single submitter	clinical testing	Invitae	Dec 18, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	Oct 24, 2022	The TSC2 c.3962A>T (p.Glu1321Val) missense change has a maximum subpopulation frequency of 0.00090% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). The in silico tool REVEL is inconclusive about a pathogenic or benign effect of this variant on protein function, and to our knowledge functional studies have not been performed. To our knowledge, this variant has not been reported in the literature in individuals with tuberous sclerosis complex. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

Tuberous sclerosis syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

May 31, 2023

This missense variant replaces glutamic acid with valine at codon 1321 of the TSC2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with tuberous sclerosis complex in the literature. This variant has been identified in 1/244910 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 13, 2019

In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 24728327) -

Isolated focal cortical dysplasia type II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Oct 27, 2023

- -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 15, 2023

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

not specified Other:1

not provided, no classification provided

reference population

ITMI

Sep 19, 2013

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	21
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.61	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.35
Eigen_PC	Benign	-0.41
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Benign	0.40	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.35	D
MutationAssessor	Benign	1.9	L;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Benign	0.46	T
PROVEAN	Uncertain	-2.4	N;.;.;N;.;D;.;.;N;D;.;.;.;.;D
REVEL	Uncertain	0.59
Sift	Uncertain	0.0030	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Benign	0.089	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.99	D;.;.;.;P;P;.;.;P;P;.;.;.;.;.
Vest4		0.39
MutPred		0.28		Gain of helix (P = 0.1736);.;.;.;.;.;.;Gain of helix (P = 0.1736);.;.;.;.;.;.;.;
MVP		0.91
ClinPred		0.34	T
GERP RS		2.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.24
gMVP		0.47

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: rs587778736; hg19: chr16-2133774;