rs770834438

Positions:

• chr9-132897226-A-C
• chr9-132897226-A-G
• chr9-132897226-A-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 1P and 7B. PP2 BP4_Moderate BP6 BS2

The NM_000368.5(TSC1):​c.2933T>G​(p.Leu978Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000752 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign 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. L978V) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 1.30

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.22033373).
• BP6: Variant 9-132897226-A-C is Benign according to our data. Variant chr9-132897226-A-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 428188.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
• BS2: High AC in GnomAdExome4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2933T>G	p.Leu978Arg	missense_variant	22/23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.2933T>G	p.Leu978Arg	missense_variant	22/23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2933T>G	p.Leu978Arg	missense_variant	23/24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251484 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000980

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461888 Hom.: 0 Cov.: 33 AF XY: 0.00000963 AC XY: 7 AN XY: 727244

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 19, 2023

The p.L978R variant (also known as c.2933T>G), located in coding exon 20 of the TSC1 gene, results from a T to G substitution at nucleotide position 2933. The leucine at codon 978 is replaced by arginine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. 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. -

Tuberous sclerosis 1 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 23, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.070
BayesDel_addAF	Benign	-0.045	T
BayesDel_noAF	Benign	-0.10
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	T;.;T;.;.;T;.;T;.;.;.
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.86	.;D;D;D;D;.;.;.;D;D;.
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.22	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.28	T
MutationAssessor	Benign	1.9	M;.;M;.;.;M;.;M;.;.;.
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-0.57	N;N;N;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.40
Sift	Uncertain	0.0040	D;D;D;.;.;.;.;.;.;.;.
Sift4G	Benign	0.28	T;T;T;.;.;.;.;.;.;.;.
Polyphen		0.96	P;.;P;.;.;P;.;P;.;.;.
Vest4		0.30
MutPred		0.30		Loss of loop (P = 0.0073);.;Loss of loop (P = 0.0073);.;.;Loss of loop (P = 0.0073);.;Loss of loop (P = 0.0073);.;.;.;
MVP		0.50
MPC		0.74
ClinPred		0.40	T
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.30
gMVP		0.56

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs770834438; hg19: chr9-135772613;