rs777592623

chr16-2086268-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000548.5(TSC2):c.4738C>T(p.Arg1580Trp) variant causes a missense change. The variant allele was found at a frequency of 0.0000131 in 152,188 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R1580Q) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 34)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 4.04

Genes affected

TSC2 (HGNC:12363): (TSC complex subunit 2) This gene is a tumor suppressor gene that encodes the growth inhibitory protein tuberin. Tuberin interacts with hamartin to form the TSC protein complex which functions in the control of cell growth. This TSC protein complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 15 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.4738C>T	p.Arg1580Trp	missense_variant	37/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.4738C>T	p.Arg1580Trp	missense_variant	37/42	5	NM_000548.5

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152188 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000800 AC: 2 AN: 249958 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135656

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000888

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152188 Hom.: 0 Cov.: 34 AF XY: 0.0000269 AC XY: 2 AN XY: 74356

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Invitae	Nov 12, 2023	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Athena Diagnostics

Jun 04, 2019

- -

Isolated focal cortical dysplasia type II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

May 05, 2023

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 22, 2022

The p.R1580W variant (also known as c.4738C>T), located in coding exon 36 of the TSC2 gene, results from a C to T substitution at nucleotide position 4738. The arginine at codon 1580 is replaced by tryptophan, an amino acid with dissimilar properties. This amino acid position is poorly conserved in available vertebrate species. One functional study reported that this variant behaved similarly to wild-type as assessed by GAP activity levels (Hansmann P. et al. Structure. 2020 08;28(8):933-942). In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.11
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Benign	-0.028
Eigen_PC	Benign	-0.014
FATHMM_MKL	Benign	0.75	D
LIST_S2	Uncertain	0.94	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.46	D
MetaRNN	Uncertain	0.54	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Benign	-0.15	N;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	0.52	D;D;D;N;N;N;N
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.1	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.60
Sift	Uncertain	0.022	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.0050	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		1.0	D;.;.;.;P;P;.;.;D;P;.;.;.;.;.
Vest4		0.56
MVP		0.87
ClinPred		0.79	D
GERP RS		2.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.47
gMVP		0.68

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: rs777592623; hg19: chr16-2136269;