9-132912282-C-T

Variant names:

• chr9-132912282-C-T
• rs118203468
• NM_000368.5:c.913G>A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000368.5(TSC1):​c.913G>A​(p.Gly305Arg) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G305W) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.18

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 16 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-132912282-C-A is described in Lovd as [Pathogenic].
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 9-132912282-C-T is Pathogenic according to our data. Variant chr9-132912282-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 49125.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-132912282-C-T is described in Lovd as [Likely_pathogenic]. Variant chr9-132912282-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.913G>A	p.Gly305Arg	missense_variant, splice_region_variant	Exon 9 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.913G>A	p.Gly305Arg	missense_variant, splice_region_variant	Exon 9 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.913G>A	p.Gly305Arg	missense_variant, splice_region_variant	Exon 10 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

May 13, 2022

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Located at the last nucleotide of the exon in a gene for which loss-of-function is a known mechanism of disease, and splice predictors support a deleterious effect; Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 21309039, 18830229, 17304050, 33588785, 18466115) -

Hereditary cancer-predisposing syndrome Pathogenic:1

Apr 28, 2020

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G305R variant (also known as c.913G>A), located in coding exon 7 of the TSC1 gene, results from a G to A substitution at nucleotide position 913. The amino acid change results in glycine to arginine at codon 305, an amino acid with dissimilar properties. However, this change occurs in the last base pair of coding exon 7, which makes it likely to have some effect on normal mRNA splicing. This alteration has been reported to segregate with affected relatives only in family diagnosed with tuberous sclerosis complex (Au KS et al. Genet. Med. 2007 Feb;9:88-100). This nucleotide position is highly conserved in available vertebrate species. Using two different splice site prediction tools, this alteration is predicted by BDGP to abolish the native splice donor site, but is predicted to weaken (but not abolish) the efficiency of the native splice donor site by ESEfinder; however, direct evidence is unavailable. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

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

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.51	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.92	.;D;D;D;.;.;.;D;D;.;D;.;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Uncertain	0.72	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.59	D
MutationAssessor	Uncertain	2.5	M;.;M;.;M;.;M;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.8	N;N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.
REVEL	Pathogenic	0.76
Sift	Benign	0.059	T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
Sift4G	Uncertain	0.037	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.
Polyphen		0.34	B;.;B;.;B;.;B;.;.;.;.;D;D;D;.;.;.;D;.
Vest4		0.80
MutPred		0.58		Gain of solvent accessibility (P = 0.0456);.;Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);.;.;Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);Gain of solvent accessibility (P = 0.0456);.;Gain of solvent accessibility (P = 0.0456);.;
MVP		0.85
MPC		1.5
ClinPred		0.98	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.20
gMVP		0.64

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.59		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.59		Position offset: -16
DS_DL_spliceai		0.45		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs118203468; hg19: chr9-135787669;