NM_000368.5:c.1949A>G

Variant names:

• chr9-132905629-T-C
• rs939275328
• NM_000368.5:c.1949A>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 6P and 1B. PM2 PP3_Strong BP6

The NM_000368.5(TSC1):​c.1949A>G​(p.Asp650Gly) 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D650N) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 7.82
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, PanelApp Australia, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• lung lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.964
• BP6: Variant 9-132905629-T-C is Benign according to our data. Variant chr9-132905629-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 466052.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.1949A>G	p.Asp650Gly	missense_variant	Exon 15 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.1949A>G	p.Asp650Gly	missense_variant	Exon 15 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.1949A>G	p.Asp650Gly	missense_variant	Exon 16 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Aug 28, 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 aspartic acid with glycine at codon 650 of the TSC1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 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 1/31412 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. -

not provided Uncertain:1

Jun 16, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 29, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D650G variant (also known as c.1949A>G), located in coding exon 13 of the TSC1 gene, results from an A to G substitution at nucleotide position 1949. The aspartic acid at codon 650 is replaced by glycine, an amino acid with similar 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. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Tuberous sclerosis 1 Benign:1

Nov 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.74
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;.;D;.;.;D;.;D;.;.;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.95	.;D;D;D;D;.;.;.;D;D;.
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.96	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Uncertain	2.5	M;.;M;.;.;M;.;M;.;.;.
PhyloP100		7.8
PrimateAI	Uncertain	0.53	T
PROVEAN	Pathogenic	-5.3	D;D;D;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0080	D;D;D;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.0060	D;D;D;.;.;.;.;.;.;.;.
Polyphen		1.0	D;.;D;.;.;D;.;D;.;.;.
Vest4		0.94
MutPred		0.83		Loss of stability (P = 0.117);.;Loss of stability (P = 0.117);.;.;Loss of stability (P = 0.117);.;Loss of stability (P = 0.117);.;Loss of stability (P = 0.117);.;
MVP		0.97
MPC		1.6
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.71
gMVP		0.77
Mutation Taster		=38/62	disease causing

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

Other links and lift over

dbSNP: rs939275328; hg19: chr9-135781016;