9-132927201-C-G

Position:

• chr9-132927201-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_000368.5(TSC1):​c.210G>C​(p.Lys70Asn) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. 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. K70E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.89

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_pathogenic. Variant got 7 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: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC1	NM_000368.5	c.210G>C	p.Lys70Asn	missense_variant, splice_region_variant	4/23	ENST00000298552.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC1	ENST00000298552.9	c.210G>C	p.Lys70Asn	missense_variant, splice_region_variant	4/23	1	NM_000368.5	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

Tuberous sclerosis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 20, 2020

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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. 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: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with TSC1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with asparagine at codon 70 of the TSC1 protein (p.Lys70Asn). The lysine residue is highly conserved and there is a moderate physicochemical difference between lysine and asparagine. This variant also falls at the last nucleotide of exon 4 of the TSC1 coding sequence, which is part of the consensus splice site for this exon. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.;.;.
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.51	.;T;D;D;.;.;.;D;D;.;T;.;.;D;D;D;T;D;D;D;D
M_CAP	Pathogenic	0.37	D
MetaRNN	Pathogenic	0.80	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.86	D
MutationAssessor	Uncertain	2.5	M;M;M;.;M;.;M;.;.;M;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;N
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-2.9	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.
REVEL	Pathogenic	0.79
Sift	Uncertain	0.0080	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.
Sift4G	Pathogenic	0.0	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.
Polyphen		1.0	D;.;D;.;D;.;D;.;.;.;.;D;D;D;.;.;.;D;.;.;.
Vest4		0.91
MutPred		0.53		Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);Loss of methylation at K70 (P = 0.011);
MVP		0.87
MPC		1.5
ClinPred		0.98	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.52
gMVP		0.65

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.87		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.87		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1060503219; hg19: chr9-135802588;