rs370916731

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2BP4_ModerateBP6

The NM_000368.5(TSC1):​c.899C>T​(p.Thr300Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,614,082 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

TSC1
NM_000368.5 missense

Scores

6
13

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:2

Conservation

PhyloP100: 4.61
Variant links:
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.1915966).
BP6
Variant 9-132912296-G-A is Benign according to our data. Variant chr9-132912296-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 411242.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Benign=1, Uncertain_significance=4}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TSC1NM_000368.5 linkc.899C>T p.Thr300Ile missense_variant Exon 9 of 23 ENST00000298552.9 NP_000359.1 Q92574-1Q86WV8X5D9D2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TSC1ENST00000298552.9 linkc.899C>T p.Thr300Ile missense_variant Exon 9 of 23 1 NM_000368.5 ENSP00000298552.3 Q92574-1
TSC1ENST00000490179.4 linkc.899C>T p.Thr300Ile missense_variant Exon 10 of 24 3 ENSP00000495533.2 A0A2R8Y6S8

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.00000398
AC:
1
AN:
251256
Hom.:
0
AF XY:
0.00000737
AC XY:
1
AN XY:
135766
show subpopulations
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:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000881
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461846
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
727220
show subpopulations
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:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000180
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74378
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000147
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.0000151
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.0000165
AC:
2
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:4Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:1Benign:2
Nov 07, 2021
Genome-Nilou Lab
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jan 23, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jan 08, 2024
Clinical Genomics Laboratory, Washington University in St. Louis
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

A TSC1 c.899C>T (p.Thr300Ile) variant was identified at a heterozygous allelic fraction of 49%, a frequency consistent with germline origin. This variant, to our knowledge, has not been reported in the medical literature and is only observed on 3/780,974 alleles in the general population (gnomAD v.4.0.0), indicating it is not a common variant. This variant has been reported in the ClinVar database by four submitters (ClinVar ID: 411242), but with conflicting interpretations. Computational predictors are uncertain as to the impact of this variant on TSC1 function. Due to limited and conflicting information, and based on ACMG/AMP guidelines for variant interpretation (Richards S et al., PMID: 25741868), the clinical significance of the TSC1 c.899C>T (p.Thr300Ile) variant is uncertain at this time. -

Tuberous sclerosis syndrome Uncertain:1
Aug 13, 2024
All of Us Research Program, National Institutes of Health
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This missense variant replaces threonine with isoleucine at codon 300 of the TSC1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/251256 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Isolated focal cortical dysplasia type II Uncertain:1
Oct 30, 2023
Baylor Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1
Oct 24, 2024
Ambry Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The p.T300I variant (also known as c.899C>T), located in coding exon 7 of the TSC1 gene, results from a C to T substitution at nucleotide position 899. The threonine at codon 300 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is not well 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.089
BayesDel_addAF
Uncertain
0.043
T
BayesDel_noAF
Benign
-0.16
CADD
Benign
19
DANN
Benign
0.94
DEOGEN2
Uncertain
0.42
T;.;T;.;T;.;T;.;.;.;.;.;.;.;.;.;.;T;.
Eigen
Benign
0.018
Eigen_PC
Uncertain
0.24
FATHMM_MKL
Uncertain
0.91
D
LIST_S2
Benign
0.83
.;T;T;T;.;.;.;T;T;.;T;.;.;T;T;T;T;T;T
M_CAP
Benign
0.038
D
MetaRNN
Benign
0.19
T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM
Uncertain
-0.086
T
MutationAssessor
Benign
1.7
L;.;L;.;L;.;L;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI
Benign
0.47
T
PROVEAN
Benign
0.51
N;N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.
REVEL
Uncertain
0.29
Sift
Benign
0.44
T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.
Sift4G
Benign
0.49
T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.
Polyphen
0.0070
B;.;B;.;B;.;B;.;.;.;.;B;B;B;.;.;.;B;.
Vest4
0.23
MVP
0.50
MPC
0.59
ClinPred
0.26
T
GERP RS
5.9
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.079
gMVP
0.26

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

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs370916731; hg19: chr9-135787683; API