rs45517388

chr16-2087929-C-Achr16-2087929-C-Gchr16-2087929-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP3 PP5_Moderate

The NM_000548.5(TSC2):c.5056C>A(p.Gln1686Lys) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q1686P) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.84

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 14 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-2087930-A-C is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.794
• PP5: Variant 16-2087929-C-A is Pathogenic according to our data. Variant chr16-2087929-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1802241.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.5056C>A	p.Gln1686Lys	missense_variant	39/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.5056C>A	p.Gln1686Lys	missense_variant	39/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Diagnostics Services (NGS), CSIR - Centre For Cellular And Molecular Biology

Aug 30, 2022

The c.5056C>A variant is not present in 1000 Genomes, EVS, gnomAD and Indian Exome Database. The variant is not present in our in-house exome database. In-silico pathogenicity prediction programs like PolyPhen-2, MutationTaster2, CADD, Varsome etc. predicted this variant to be likely deleterious, however these predictions were not confirmed by any published functional studies. The variant is located in a dense mutational hotspot region of the gene and an alternative variant (c.5056C>T) in the same location was previously identified and reported to HGMD (ID: CM052387) in patients affected with Tuberous sclerosis [5]. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.20
Cadd	Uncertain	26
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.64	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.29
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.94	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.79	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.50	D
MutationAssessor	Benign	1.2	L;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.3	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Pathogenic	0.76
Sift	Benign	0.32	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.074	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.97	D;.;.;.;P;P;.;.;P;D;.;.;.;.;.
Vest4		0.79
MutPred		0.62		Gain of methylation at Q1686 (P = 0.0301);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.88
ClinPred		0.91	D
GERP RS		4.6
Varity_R		0.68
gMVP		0.71

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: rs45517388; hg19: chr16-2137930;