NM_000368.5:c.518C>A

Variant names:

• chr9-132921964-G-T
• rs777484049
• NM_000368.5:c.518C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000368.5(TSC1):​c.518C>A​(p.Ala173Glu) 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 benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A173V) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.03
• 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.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 22 uncertain in NM_000368.5
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3099048).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000368.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC1	NM_000368.5	MANE Select	c.518C>A	p.Ala173Glu	missense	Exon 7 of 23	NP_000359.1
	TSC1	NM_001406592.1		c.518C>A	p.Ala173Glu	missense	Exon 7 of 23	NP_001393521.1
	TSC1	NM_001406593.1		c.518C>A	p.Ala173Glu	missense	Exon 7 of 23	NP_001393522.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC1	ENST00000298552.9	TSL:1 MANE Select	c.518C>A	p.Ala173Glu	missense	Exon 7 of 23	ENSP00000298552.3
	TSC1	ENST00000490179.4	TSL:3	c.518C>A	p.Ala173Glu	missense	Exon 8 of 24	ENSP00000495533.2
	TSC1	ENST00000403810.6	TSL:1	c.518C>A	p.Ala173Glu	missense	Exon 7 of 10	ENSP00000386093.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Jul 15, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A173E variant (also known as c.518C>A), located in coding exon 5 of the TSC1 gene, results from a C to A substitution at nucleotide position 518. The alanine at codon 173 is replaced by glutamic acid, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.030
CADD	Uncertain	23
DANN	Uncertain	0.97
DEOGEN2	Benign	0.41	T
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D
M_CAP	Benign	0.067	D
MetaRNN	Benign	0.31	T
MetaSVM	Uncertain	-0.026	T
MutationAssessor	Benign	1.1	L
PhyloP100		8.0
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-0.22	N
REVEL	Benign	0.28
Sift	Benign	0.19	T
Sift4G	Benign	0.10	T
Polyphen		0.0050	B
Vest4		0.45
MutPred		0.36		Gain of sheet (P = 0.039)
MVP		0.25
MPC		0.93
ClinPred		0.59	D
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.077
gMVP		0.19
Mutation Taster		=60/40	polymorphism

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: rs777484049; hg19: chr9-135797351;