chr9-132921429-A-T

Position:

• chr9-132921429-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PM5 PP2 PP3_Moderate

The NM_000368.5(TSC1):​c.671T>A​(p.Met224Lys) variant causes a missense change involving the alteration of a conserved nucleotide. 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. M224R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.05

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_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-132921429-A-C is described in Lovd as [Pathogenic].
• 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, 0.929

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC1	NM_000368.5	c.671T>A	p.Met224Lys	missense_variant	8/23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.671T>A	p.Met224Lys	missense_variant	8/23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.671T>A	p.Met224Lys	missense_variant	9/24	3		ENSP00000495533.2

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

May 05, 2018

This sequence change replaces methionine with lysine at codon 224 of the TSC1 protein (p.Met224Lys). The methionine residue is moderately conserved and there is a moderate physicochemical difference between methionine and lysine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with TSC1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	.;D;D;D;.;.;.;D;D;.;D;.;.;D;D;D;D;D;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.60	D
MutationAssessor	Uncertain	2.3	M;.;M;.;M;.;M;.;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.77	T
PROVEAN	Uncertain	-4.1	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Sift4G	Uncertain	0.0030	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Polyphen		0.96	D;.;D;.;D;.;D;.;.;.;.;D;D;D;.;.;.;D;.;.
Vest4		0.84
MutPred		0.78		Loss of helix (P = 0.028);.;Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);.;.;Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);Loss of helix (P = 0.028);.;Loss of helix (P = 0.028);.;Loss of helix (P = 0.028);
MVP		0.88
MPC		1.7
ClinPred		0.99	D
GERP RS		5.1
Varity_R		0.88
gMVP		0.89

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs118203426; hg19: chr9-135796816;