9-132912413-T-G

Position:

• chr9-132912413-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_000368.5(TSC1):​c.782A>C​(p.Lys261Thr) variant causes a missense change. 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. K261R) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.27

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 5 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, 0.865

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC1	NM_000368.5	c.782A>C	p.Lys261Thr	missense_variant	9/23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.782A>C	p.Lys261Thr	missense_variant	9/23	1	NM_000368.5	ENSP00000298552	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

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 11, 2016

The p.K261T variant (also known as c.782A>C), located in coding exon 7 of the TSC1 gene, results from an A to C substitution at nucleotide position 782. The lysine at codon 261 is replaced by threonine, an amino acid with similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.01% (greater than 10000 alleles tested) in our clinical cohort. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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	Pathogenic	0.74
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	.;D;D;D;.;.;.;D;D;.;D;.;.;D;D;D;D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Uncertain	2.5	M;.;M;.;M;.;M;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-3.4	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
REVEL	Pathogenic	0.87
Sift	Uncertain	0.0060	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
Sift4G	Uncertain	0.0060	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
Polyphen		0.99	D;.;D;.;D;.;D;.;.;.;.;D;D;D;.;.;.;D;.
Vest4		0.86
MutPred		0.58		Loss of ubiquitination at K261 (P = 0.0081);.;Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);.;.;Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);Loss of ubiquitination at K261 (P = 0.0081);.;Loss of ubiquitination at K261 (P = 0.0081);.;
MVP		0.93
MPC		1.5
ClinPred		0.99	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.45
gMVP		0.63

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: rs371225009; hg19: chr9-135787800;