rs796053479

Positions:

• chr16-2088575-A-C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_000548.5(TSC2):​c.5389A>C​(p.Ile1797Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,152 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict 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. I1797M) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 3.15

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 -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14427978).
• BP6: Variant 16-2088575-A-C is Benign according to our data. Variant chr16-2088575-A-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 207696.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=3, Likely_benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.5389A>C	p.Ile1797Leu	missense_variant	42/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.5389A>C	p.Ile1797Leu	missense_variant	42/42	5	NM_000548.5

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152152 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 33

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152152 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74314

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 16, 2024	This sequence change replaces isoleucine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 1797 of the TSC2 protein (p.Ile1797Leu). 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: 207696). 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. -

Isolated focal cortical dysplasia type II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Feb 14, 2024

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 03, 2023

The p.I1797L variant (also known as c.5389A>C), located in coding exon 41 of the TSC2 gene, results from an A to C substitution at nucleotide position 5389. The isoleucine at codon 1797 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is not well 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. -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Jan 20, 2014

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.099
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Benign	17
DANN	Benign	0.93
DEOGEN2	Benign	0.41	T;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.82
Eigen_PC	Benign	-0.72
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.81	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
M_CAP	Uncertain	0.12	D
MetaRNN	Benign	0.14	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.58	T
MutationAssessor	Benign	1.6	L;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	0.99	D;D;D;D;D;D;D
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-0.62	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.45
Sift	Benign	0.054	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.22	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.33	B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.41
MutPred		0.27		Gain of disorder (P = 0.0606);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.75
ClinPred		0.22	T
GERP RS		0.96
Varity_R		0.086
gMVP		0.29

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: rs796053479; hg19: chr16-2138576;