rs137854883

Positions:

• chr16-2088139-T-A
• chr16-2088139-T-C
• chr16-2088139-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000548.5(TSC2):​c.5160T>A​(p.Asn1720Lys) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense, splice_region
• Scores: Splicing: ADA: 0.00007197
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: -1.68

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 6 ACMG points.

• PM1: In a domain Rap-GAP (size 227) in uniprot entity TSC2_HUMAN there are 284 pathogenic changes around while only 47 benign (86%) in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.903

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.5160T>A	p.Asn1720Lys	missense_variant, splice_region_variant	40/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.5160T>A	p.Asn1720Lys	missense_variant, splice_region_variant	40/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 09, 2022

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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Experimental studies and prediction algorithms are not available or were not evaluated, and the effect of this variant on mRNA splicing is currently unknown. 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: "Benign"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 49356). This missense change has been observed in individual(s) with clinical features of tuberous sclerosis complex (PMID: 17304050). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 1720 of the TSC2 protein (p.Asn1720Lys). It affects a nucleotide within the consensus splice site. -

Tuberous sclerosis syndrome Other:1

not provided, no classification provided

curation

Tuberous sclerosis database (TSC2)

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.030
CADD	Benign	0.053
DANN	Benign	0.92
DEOGEN2	Pathogenic	0.97	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.36	N
LIST_S2	Uncertain	0.91	D;D;D;D;D;D;D;D;D;D;T;D;D;T;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.70	D
MutationAssessor	Pathogenic	2.9	M;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-4.8	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.56
Sift	Uncertain	0.0020	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.0080	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.37	B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.95
MutPred		0.77		Gain of MoRF binding (P = 0.0234);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.97
ClinPred		0.97	D
GERP RS		-3.8
Varity_R		0.91
gMVP		0.82

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000072
dbscSNV1_RF	Benign	0.12
SpliceAI score (max)		0.010		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: rs137854883; hg19: chr16-2138140;