9-132921429-A-G

Variant names:

• chr9-132921429-A-G
• rs118203426
• NM_000368.5:c.671T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000368.5(TSC1):​c.671T>C​(p.Met224Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,834 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. M224L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• 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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 14 uncertain in NM_000368.5
• 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 ClinVar as [Likely_pathogenic]. Clinvar id is 5104.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.872

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.671T>C	p.Met224Thr	missense_variant	Exon 8 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.671T>C	p.Met224Thr	missense_variant	Exon 8 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.671T>C	p.Met224Thr	missense_variant	Exon 9 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461834 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727222

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

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

May 04, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; 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 methionine with threonine at codon 224 of the TSC1 protein (p.Met224Thr). The methionine residue is moderately conserved and there is a moderate physicochemical difference between methionine and threonine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.17
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.71	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.;.
Eigen	Uncertain	0.68
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	.;D;D;D;.;.;.;D;D;.;D;.;.;D;D;D;D;D;D;D
M_CAP	Uncertain	0.15	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.47	D
MutationAssessor	Uncertain	2.3	M;.;M;.;M;.;M;.;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-3.3	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0010	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Sift4G	Uncertain	0.0050	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.
Polyphen		0.92	P;.;P;.;P;.;P;.;.;.;.;D;D;D;.;.;.;D;.;.
Vest4		0.72
MutPred		0.70		Gain of glycosylation at M224 (P = 0.0271);.;Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);.;.;Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);Gain of glycosylation at M224 (P = 0.0271);.;Gain of glycosylation at M224 (P = 0.0271);.;Gain of glycosylation at M224 (P = 0.0271);
MVP		0.74
MPC		1.5
ClinPred		0.98	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.69
gMVP		0.73

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: rs118203426; hg19: chr9-135796816;