9-132925592-G-T

Position:

• chr9-132925592-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_000368.5(TSC1):​c.358C>A​(p.Leu120Ile) 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L120F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.76

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
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TSC1. . Gene score misZ 2.3217 (greater than the threshold 3.09). Trascript score misZ 3.6986 (greater than threshold 3.09). GenCC has associacion of gene with lung lymphangioleiomyomatosis, tuberous sclerosis 1, tuberous sclerosis, tuberous sclerosis complex, lymphangioleiomyomatosis.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.818

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC1	NM_000368.5	c.358C>A	p.Leu120Ile	missense_variant	5/23	ENST00000298552.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC1	ENST00000298552.9	c.358C>A	p.Leu120Ile	missense_variant	5/23	1	NM_000368.5	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 03, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with TSC1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with isoleucine at codon 120 of the TSC1 protein (p.Leu120Ile). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and isoleucine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 18, 2024

The p.L120I variant (also known as c.358C>A), located in coding exon 3 of the TSC1 gene, results from a C to A substitution at nucleotide position 358. The leucine at codon 120 is replaced by isoleucine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.48
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.52	D;D;.;D;.;D;.;.;.;.;.;.;.;D;.;.
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	.;D;D;.;.;.;D;D;.;.;D;D;D;D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.82	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.41	D
MutationAssessor	Uncertain	2.5	M;M;.;M;.;M;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.79	T
PROVEAN	Benign	-1.4	N;N;.;.;.;.;.;.;.;.;.;.;.;N;.;.
REVEL	Uncertain	0.64
Sift	Uncertain	0.0090	D;D;.;.;.;.;.;.;.;.;.;.;.;T;.;.
Sift4G	Pathogenic	0.0	D;D;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Polyphen		0.98	D;D;.;D;.;D;.;.;D;D;D;.;.;D;.;.
Vest4		0.88
MutPred		0.71		Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);Loss of catalytic residue at L120 (P = 0.0533);
MVP		0.51
MPC		1.4
ClinPred		0.97	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.40
gMVP		0.33

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1554820263; hg19: chr9-135800979;