chr9-132921375-A-G

Position:

• chr9-132921375-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP3_Moderate

The ENST00000298552.9(TSC1):​c.725T>C​(p.Leu242Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. L242L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TSC1 ENST00000298552.9 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32

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.

• 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 ENST00000298552.9
• 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, 0.89

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC1	NM_000368.5	c.725T>C	p.Leu242Pro	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.725T>C	p.Leu242Pro	missense_variant	8/23	1	NM_000368.5	ENSP00000298552	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461822 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727212

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 30, 2017

This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TSC1-related disease. In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. 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"). This sequence change replaces leucine with proline at codon 242 of the TSC1 protein (p.Leu242Pro). The leucine residue is moderately conserved and there is a moderate physicochemical difference between leucine and proline. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.79	D;.;D;.;D;.;D;.;.;.;.;.;.;.;.;.;.;D;.
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	.;D;D;D;.;.;.;D;D;.;D;.;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.35	D
MetaRNN	Pathogenic	0.89	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;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-4.2	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0040	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
Sift4G	Uncertain	0.0030	D;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.
Polyphen		1.0	D;.;D;.;D;.;D;.;.;.;.;D;D;D;.;.;.;D;.
Vest4		0.90
MutPred		0.68		Gain of disorder (P = 0.033);.;Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);.;.;Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);Gain of disorder (P = 0.033);.;Gain of disorder (P = 0.033);.;
MVP		0.82
MPC		1.8
ClinPred		0.99	D
GERP RS		6.0
Varity_R		0.73
gMVP		0.89

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: rs1554819388; hg19: chr9-135796762;