chr9-132921818-C-T

Variant names:

• chr9-132921818-C-T
• rs118203419
• NM_000368.5:c.663+1G>A

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.663+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 7.91

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: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-132921818-C-T is Pathogenic according to our data. Variant chr9-132921818-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 49076.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-132921818-C-T is described in Lovd as [Pathogenic]. Variant chr9-132921818-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.663+1G>A		splice_donor_variant, intron_variant	Intron 7 of 22	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.663+1G>A		splice_donor_variant, intron_variant	Intron 7 of 22	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.663+1G>A		splice_donor_variant, intron_variant	Intron 8 of 23	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 1 Pathogenic:2

Nov 07, 2021

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 11, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). This variant has been reported in individuals in the Leiden Open-source Variation Database (PMID: 21520333). ClinVar contains an entry for this variant (Variation ID: 49076). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in intron 7 of the TSC1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

not provided Pathogenic:1

Sep 26, 2019

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (Lek 2016); This variant is associated with the following publications: (PMID: 15798777, 12853839, 10227394, 17304050) -

Malignant tumor of urinary bladder Other:1

-

Tuberous sclerosis database (TSC1)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Uncertain	0.96	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs118203419; hg19: chr9-135797205; COSMIC: COSV53767552; COSMIC: COSV53767552;