rs118203650

Variant names:

• chr9-132903713-TC-T
• rs118203650
• NM_000368.5:c.2145delG

Variant summary

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

The NM_000368.5(TSC1):​c.2145delG​(p.Asn716ThrfsTer8) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R715LNMRLLRK?) has been classified as Pathogenic. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 0.383

Genes affected

TSC1 (HGNC:12362): (TSC complex subunit 1) This gene is a tumor suppressor gene that encodes the growth inhibitory protein hamartin. The encoded protein interacts with and stabilizes the GTPase activating protein tuberin. This hamartin-tuberin complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. This protein also functions as a co-chaperone for Hsp90 that inhibits its ATPase activity. This protein functions as a facilitator of Hsp90-mediated folding of kinase and non-kinase clients, including TSC2 and thereby preventing their ubiquitination and proteasomal degradation. 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 9-132903713-TC-T is Pathogenic according to our data. Variant chr9-132903713-TC-T is described in ClinVar as [Pathogenic]. Clinvar id is 48910.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-132903713-TC-T is described in Lovd as [Pathogenic]. Variant chr9-132903713-TC-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2145delG	p.Asn716ThrfsTer8	frameshift_variant	Exon 17 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.2145delG	p.Asn716ThrfsTer8	frameshift_variant	Exon 17 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2145delG	p.Asn716ThrfsTer8	frameshift_variant	Exon 18 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 1 Pathogenic:2

Sep 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Asn716Thrfs*8) in the TSC1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). This premature translational stop signal has been observed in individual(s) with tuberous sclerosis complex (PMID: 9328481). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 48910). This variant is also known as c.2365delG. -

Nov 07, 2021

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Mar 01, 2019

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2145delG pathogenic variant in the TSC1 gene has been reported previously as c.2365delG due to the use of alternative nomenclature in individuals with a clinical diagnosis of tuberous sclerosis complex (Jones et al., 1997; Dabora et al., 1998). The deletion causes a frameshift starting with codon Asparagine 716, changes this amino acid to a Threonine residue and creates a premature Stop codon at position 8 of the new reading frame, denoted p.Asn716ThrfsX8. This pathogenic variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. Furthermore, the c.2145delG variant is not observed in large population cohorts (Lek et al., 2016). -

Tuberous sclerosis syndrome Other:1

-

Tuberous sclerosis database (TSC1)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs118203650; hg19: chr9-135779100;