9-132928808-C-T

Position:

• chr9-132928808-C-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 1P and 6B. PP2 BP4_Moderate BS2

The NM_000368.5(TSC1):​c.65G>A​(p.Arg22Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000185 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R22W) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000018 (0 hom.)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 1.14

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_benign. Variant got -5 ACMG points.

• PP2: Missense variant where missense usually causes diseases, TSC1
• BP4: Computational evidence support a benign effect (MetaRNN=0.07581249).
• BS2: High AC in GnomAdExome4 at 27 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC1	NM_000368.5	c.65G>A	p.Arg22Gln	missense_variant	3/23	ENST00000298552.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC1	ENST00000298552.9	c.65G>A	p.Arg22Gln	missense_variant	3/23	1	NM_000368.5	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251338 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135850

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000980

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000185 AC: 27 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.0000206 AC XY: 15 AN XY: 727238

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000139

Gnomad4 FIN exome AF: 0.0000374

Gnomad4 NFE exome AF: 0.00000989

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 11, 2023

The p.R22Q variant (also known as c.65G>A), located in coding exon 1 of the TSC1 gene, results from a G to A substitution at nucleotide position 65. The arginine at codon 22 is replaced by glutamine, an amino acid with highly similar properties. This alteration has been reported in a patient with a clinical diagnosis of tuberous sclerosis (Ismail NF et al. J Mol Diagn, 2017 03;19:265-276). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Tuberous sclerosis 1 Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.093
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.30
CADD	Benign	16
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.42	T;.;T;.;T;.;T;.;.;.;.;.;.;.;.;.;.;T;.;.;.
Eigen	Benign	-0.75
Eigen_PC	Benign	-0.69
FATHMM_MKL	Benign	0.43	N
M_CAP	Benign	0.069	D
MetaRNN	Benign	0.076	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.80	T
MutationAssessor	Benign	1.1	L;L;L;.;L;.;L;.;.;L;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	0.070	N;N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.;.;.
REVEL	Benign	0.076
Sift	Benign	0.34	T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.
Sift4G	Benign	0.12	T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.
Polyphen		0.0040	B;.;B;.;B;.;B;.;.;.;.;B;B;B;.;.;.;B;.;.;.
Vest4		0.19
MVP		0.63
MPC		0.58
ClinPred		0.079	T
GERP RS		0.75
Varity_R		0.014
gMVP		0.23

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: rs141736779; hg19: chr9-135804195;