9-132903697-C-G

Variant names:

• chr9-132903697-C-G
• rs769566267
• NM_000368.5:c.2162G>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000368.5(TSC1):​c.2162G>C​(p.Arg721Pro) variant causes a missense 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. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.90

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.754

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2162G>C	p.Arg721Pro	missense_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.2162G>C	p.Arg721Pro	missense_variant	Exon 17 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2162G>C	p.Arg721Pro	missense_variant	Exon 18 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251238 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135784

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Aug 15, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with proline at codon 721 of the TSC1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with TSC1-related disorders in the literature. This variant has been identified in 1/251238 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Tuberous sclerosis 1 Uncertain:1

Sep 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 721 of the TSC1 protein (p.Arg721Pro). This variant is present in population databases (rs769566267, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with TSC1-related conditions. ClinVar contains an entry for this variant (Variation ID: 842823). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt TSC1 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Dec 09, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R721P variant (also known as c.2162G>C), located in coding exon 15 of the TSC1 gene, results from a G to C substitution at nucleotide position 2162. The arginine at codon 721 is replaced by proline, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.57	D;.;D;.;.;D;.;D;.;.;.
Eigen	Uncertain	0.66
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.94	.;D;D;D;D;.;.;.;D;D;.
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.75	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Uncertain	2.0	M;.;M;.;.;M;.;M;.;.;.
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-3.0	D;D;D;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.63
Sift	Benign	0.25	T;T;T;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.033	D;D;D;.;.;.;.;.;.;.;.
Polyphen		1.0	D;.;D;.;.;D;.;D;.;.;.
Vest4		0.90
MutPred		0.32		Loss of MoRF binding (P = 0.0152);.;Loss of MoRF binding (P = 0.0152);.;.;Loss of MoRF binding (P = 0.0152);.;Loss of MoRF binding (P = 0.0152);.;.;.;
MVP		0.87
MPC		1.5
ClinPred		0.98	D
GERP RS		5.2
Varity_R		0.75
gMVP		0.84

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs769566267; hg19: chr9-135779084;