16-2081734-C-G

Position:

• chr16-2081734-C-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000548.5(TSC2):​c.3750C>G​(p.Tyr1250Ter) variant causes a stop gained change involving the alteration of a non-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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 34)
• Consequence: TSC2 NM_000548.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 0.290

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 Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-2081734-C-G is Pathogenic according to our data. Variant chr16-2081734-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 49550.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-2081734-C-G is described in Lovd as [Pathogenic]. Variant chr16-2081734-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.3750C>G	p.Tyr1250Ter	stop_gained	31/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.3750C>G	p.Tyr1250Ter	stop_gained	31/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Dec 13, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Division of Genomic Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University	Jul 19, 2022	- -

Tuberous sclerosis syndrome Pathogenic:1 Other:1

not provided, no classification provided	curation	Tuberous sclerosis database (TSC2)	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 20, 2018	The p.Tyr1250X variant in TSC2 has been reported in 5 individuals with tuberous sclerosis complex (TSC; Dabora 2001, Tyburczy 2014, Cai 2017, Tuberous sclerosis LOVD database: http://chromium.lovd.nl/LOVD2/TSC) and was absent from large pop ulation studies. This nonsense variant leads to a premature termination codon at position 1250, which is predicted to lead to a truncated or absent protein. Het erozygous loss of function of the TSC2 gene is an established disease mechanism in individuals with TSC. In summary, this variant meets criteria to be classifie d as pathogenic for TSC in an autosomal dominant manner based upon presence in m ultiple affected individuals, absence from the general population and predicted impact to protein. ACMG/AMP Criteria applied: PVS1, PM2, PS4_Moderate. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Uncertain	0.26
Eigen_PC	Benign	0.039
FATHMM_MKL	Uncertain	0.90	D
MutationTaster	Benign	1.0	A;A;A;A;A;A;A
Vest4		0.95
GERP RS		2.7

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: rs45517308; hg19: chr16-2131735;