rs1554816070

chr9-132906106-G-Achr9-132906106-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_000368.5(TSC1):c.1472C>T(p.Thr491Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. T491R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.16

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
• PP2: Missense variant where missense usually causes diseases, TSC1

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC1	NM_000368.5	c.1472C>T	p.Thr491Ile	missense_variant	15/23	ENST00000298552.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC1	ENST00000298552.9	c.1472C>T	p.Thr491Ile	missense_variant	15/23	1	NM_000368.5	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 08, 2020

In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TSC1-related disease. This sequence change replaces threonine with isoleucine at codon 491 of the TSC1 protein (p.Thr491Ile). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Uncertain	0.065	T
BayesDel_noAF	Benign	-0.14
Cadd	Uncertain	25
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.52	D;.;D;.;.;D;.;D;.;.;.
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Uncertain	0.93	D
M_CAP	Benign	0.072	D
MetaRNN	Uncertain	0.43	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.23	D
MutationAssessor	Uncertain	2.3	M;.;M;.;.;M;.;M;.;.;.
MutationTaster	Benign	0.52	D;D;D;D
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-1.6	N;N;N;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.39
Sift	Benign	0.034	D;D;D;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.051	T;T;T;.;.;.;.;.;.;.;.
Polyphen		0.90	P;.;P;.;.;P;.;P;.;.;.
Vest4		0.39
MutPred		0.51		Loss of glycosylation at T491 (P = 0.0051);.;Loss of glycosylation at T491 (P = 0.0051);.;.;Loss of glycosylation at T491 (P = 0.0051);.;Loss of glycosylation at T491 (P = 0.0051);.;Loss of glycosylation at T491 (P = 0.0051);.;
MVP		0.62
MPC		0.85
ClinPred		0.93	D
GERP RS		5.8
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.6
Varity_R		0.19
gMVP		0.28

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1554816070; hg19: chr9-135781493;