chr16-2074311-C-G

Position:

• chr16-2074311-C-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.2467C>G​(p.Leu823Val) variant causes a missense change. 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L823R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.90

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 chr16-2074312-T-G is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.873

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.2467C>G	p.Leu823Val	missense_variant	22/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.2467C>G	p.Leu823Val	missense_variant	22/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 22, 2022

The p.L823V variant (also known as c.2467C>G), located in coding exon 21 of the TSC2 gene, results from a C to G substitution at nucleotide position 2467. The leucine at codon 823 is replaced by valine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	Benign	0.30
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Pathogenic	3.1	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-2.2	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Pathogenic	0.81
Sift	Benign	0.17	T;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.016	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.99	D;.;.;.;D;D;.;.;D;P;.;.;.;.;.
Vest4		0.88
MutPred		0.74		Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);.;Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);.;Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);Loss of catalytic residue at L823 (P = 0.0273);.;
MVP		0.98
ClinPred		0.93	D
GERP RS		3.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.34
gMVP		0.70

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-2124312;