9-132903802-T-C

Variant names:

• chr9-132903802-T-C
• rs786201465
• NM_000368.5:c.2057A>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM2 PP3_Moderate BP6

The NM_000368.5(TSC1):​c.2057A>G​(p.Asp686Gly) 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. D686N) 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: 8.02
• 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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.862
• BP6: Variant 9-132903802-T-C is Benign according to our data. Variant chr9-132903802-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 184442.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2057A>G	p.Asp686Gly	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.2057A>G	p.Asp686Gly	missense_variant	Exon 17 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2057A>G	p.Asp686Gly	missense_variant	Exon 18 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000293 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:1 Benign:1

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Tuberous sclerosis syndrome Uncertain:1

May 14, 2024

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 686 of the TSC1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. 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 not been identified 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Apr 06, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2057A>G (p.D686G) alteration is located in exon 17 (coding exon 15) of the TSC1 gene. This alteration results from a A to G substitution at nucleotide position 2057, causing the aspartic acid (D) at amino acid position 686 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.70	D;.;D;.;.;D;.;D;.;.;.
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	.;D;D;D;T;.;.;.;D;T;.
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.86	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Uncertain	2.5	M;.;M;.;.;M;.;M;.;.;.
PhyloP100		8.0
PrimateAI	Uncertain	0.60	T
PROVEAN	Uncertain	-2.9	D;D;D;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0030	D;D;D;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.034	D;D;D;.;.;.;.;.;.;.;.
Polyphen		1.0	D;.;D;.;.;D;.;D;.;.;.
Vest4		0.87
MutPred		0.61		Loss of helix (P = 0.0167);.;Loss of helix (P = 0.0167);.;.;Loss of helix (P = 0.0167);.;Loss of helix (P = 0.0167);.;.;.;
MVP		0.92
MPC		1.6
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.55
gMVP		0.53
Mutation Taster		=39/61	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.34		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.34		Position offset: 15

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

Other links and lift over

dbSNP: rs786201465; hg19: chr9-135779189;