chr9-132897563-G-GT

Position:

• chr9-132897563-G-GT

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.2672dupA​(p.Asn891fs) 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 (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TSC1 NM_000368.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 1.75

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]

TSC1 (HGNC:):

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 9-132897563-G-GT is Pathogenic according to our data. Variant chr9-132897563-G-GT is described in ClinVar as [Pathogenic]. Clinvar id is 48989.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2672dupA	p.Asn891fs	frameshift_variant	21/23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.2672dupA	p.Asn891fs	frameshift_variant	21/23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2672dupA	p.Asn891fs	frameshift_variant	22/24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1179686 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 580490

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 1 Pathogenic:3

Pathogenic, no assertion criteria provided	clinical testing	Division of Genomic Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University	Jun 09, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 16, 2021	Loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). For these reasons, this variant has been classified as Pathogenic. This variant has been observed in individuals affected with tuberous sclerosis complex (PMID: 9328481, 9803264, 9863590, 10363127). This variant is also known as 2887insA and 2887_2888insA in the literature. ClinVar contains an entry for this variant (Variation ID: 48989). This sequence change creates a premature translational stop signal (p.Asn891Lysfs*13) in the TSC1 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). -

Tuberous sclerosis syndrome Pathogenic:1 Other:1

not provided, no classification provided	curation	Tuberous sclerosis database (TSC1)	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Feb 01, 2019	The p.Asn891fs variant in TSC1 has been reported in 5 individuals with tuberous sclerosis (Jones 1997, Ali 1998, Young 1998) and was absent from large population studies. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 891 and leads to a premature termination codon 13 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Heterozygous loss of function of the TSC1 gene is an established disease mechanism in individuals with tuberous sclerosis. In summary, this variant meets criteria to be classified as pathogenic for tuberous sclerosis in an autosomal dominant manner based upon predicted impact to the protein. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 03, 2019

The c.2672dupA pathogenic mutation, located in coding exon 19 of the TSC1 gene, results from a duplication of A at nucleotide position 2672, causing a translational frameshift with a predicted alternate stop codon (p.N891Kfs*13). This alteration has been identified in multiple individuals diagnosed with tuberous sclerosis and has been reported as 2887insA and 2887-2888insA in the literature (Jones AC et al. Hum. Mol. Genet., 1997 Nov;6:2155-61; Young JM et al. Ann. Hum. Genet., 1998 May;62:203-13; Ali JB et al. J. Med. Genet., 1998 Dec;35:969-72; Dabora SL et al. Ann. Hum. Genet., 1998 Nov;62:491-504). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

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: rs118203724; hg19: chr9-135772950;