9-132925723-A-T

Variant names:

• chr9-132925723-A-T
• rs118203355
• NM_000368.5:c.227T>A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000368.5(TSC1):​c.227T>A​(p.Ile76Asn) 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: 33)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 9.10

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 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.933

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.227T>A	p.Ile76Asn	missense_variant	Exon 5 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.227T>A	p.Ile76Asn	missense_variant	Exon 5 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.227T>A	p.Ile76Asn	missense_variant	Exon 6 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:1

Mar 02, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine with asparagine at codon 76 of the TSC1 protein (p.Ile76Asn). The isoleucine residue is weakly conserved and there is a large physicochemical difference between isoleucine and asparagine. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with tuberous sclerosis complex (PMID: 17304050). ClinVar contains an entry for this variant (Variation ID: 48927). This variant has been reported to affect TSC1 protein function (PMID: 21309039). 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. -

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	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.10
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D;D;.;D;.;D;.;.;.;.;.;.;.;D;.;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	.;D;D;.;.;.;D;D;.;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.43	D
MutationAssessor	Benign	1.7	L;L;.;L;.;L;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.60	T
PROVEAN	Uncertain	-3.8	D;D;.;.;.;.;.;.;.;.;.;.;.;D;.;.
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0010	D;D;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Sift4G	Uncertain	0.0030	D;D;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Polyphen		0.71	P;P;.;P;.;P;.;.;P;P;P;.;.;P;.;.
Vest4		0.94
MutPred		0.81		Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);Gain of loop (P = 0.002);
MVP		0.78
MPC		1.6
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.76
gMVP		0.73

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

Publications

LitVar

Other links and lift over

dbSNP: rs118203355; hg19: chr9-135801110;