rs533565295

Positions:

• chr9-132896654-C-A
• chr9-132896654-C-G
• chr9-132896654-C-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM2 PP2 BP4_Strong

The NM_000368.5(TSC1):​c.3076G>T​(p.Ala1026Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,226 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict 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. A1026T) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -0.790

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, TSC1
• BP4: Computational evidence support a benign effect (MetaRNN=0.01726982).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC1	NM_000368.5	c.3076G>T	p.Ala1026Ser	missense_variant	23/23	ENST00000298552.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC1	ENST00000298552.9	c.3076G>T	p.Ala1026Ser	missense_variant	23/23	1	NM_000368.5	P4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152108 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249426 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135358

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152226 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74440

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

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

Invitae

Feb 14, 2018

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with TSC1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with serine at codon 1026 of the TSC1 protein (p.Ala1026Ser). The alanine residue is weakly conserved and there is a moderate physicochemical difference between alanine and serine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 10, 2022

The p.A1026S variant (also known as c.3076G>T), located in coding exon 21 of the TSC1 gene, results from a G to T substitution at nucleotide position 3076. The alanine at codon 1026 is replaced by serine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.064
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.50
CADD	Benign	0.26
DANN	Benign	0.18
DEOGEN2	Benign	0.29	T;.;T;.;.;T;.;T;.;.;.
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.19	N
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.017	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	0.41	N;.;N;.;.;N;.;N;.;.;.
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.31	T
PROVEAN	Benign	0.11	N;N;N;.;.;.;.;.;.;.;.
REVEL	Benign	0.11
Sift	Benign	1.0	T;T;T;.;.;.;.;.;.;.;.
Sift4G	Benign	1.0	T;T;T;.;.;.;.;.;.;.;.
Polyphen		0.0010	B;.;B;.;.;B;.;B;.;.;.
Vest4		0.056
MutPred		0.24		Gain of phosphorylation at A1026 (P = 5e-04);.;Gain of phosphorylation at A1026 (P = 5e-04);.;.;Gain of phosphorylation at A1026 (P = 5e-04);.;Gain of phosphorylation at A1026 (P = 5e-04);.;.;.;
MVP		0.41
MPC		0.45
ClinPred		0.036	T
GERP RS		1.7
Varity_R		0.017
gMVP		0.15

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: rs533565295; hg19: chr9-135772041;