16-2088461-G-C

Variant names:

• chr16-2088461-G-C
• rs758450326
• NM_000548.5:c.5275G>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000548.5(TSC2):​c.5275G>C​(p.Ala1759Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A1759V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.19
• Publications: 6 publications found

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]

PKD1 (HGNC:9008): (polycystin 1, transient receptor potential channel interacting) This gene encodes a member of the polycystin protein family. The encoded glycoprotein contains a large N-terminal extracellular region, multiple transmembrane domains and a cytoplasmic C-tail. It is an integral membrane protein that functions as a regulator of calcium permeable cation channels and intracellular calcium homoeostasis. It is also involved in cell-cell/matrix interactions and may modulate G-protein-coupled signal-transduction pathways. It plays a role in renal tubular development, and mutations in this gene cause autosomal dominant polycystic kidney disease type 1 (ADPKD1). ADPKD1 is characterized by the growth of fluid-filled cysts that replace normal renal tissue and result in end-stage renal failure. Splice variants encoding different isoforms have been noted for this gene. Also, six pseudogenes, closely linked in a known duplicated region on chromosome 16p, have been described. [provided by RefSeq, Oct 2008]

PKD1 Gene-Disease associations (from GenCC):

• autosomal dominant polycystic kidney disease

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• polycystic kidney disease 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• autosomal recessive polycystic kidney disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Caroli disease

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000548.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.5275G>C	p.Ala1759Pro	missense	Exon 42 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.5272G>C	p.Ala1758Pro	missense	Exon 42 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.5206G>C	p.Ala1736Pro	missense	Exon 41 of 41	NP_001107854.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.5275G>C	p.Ala1759Pro	missense	Exon 42 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.5206G>C	p.Ala1736Pro	missense	Exon 41 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.5074G>C	p.Ala1692Pro	missense	Exon 40 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460510 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 726540

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52074

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111990

Other (OTH) AF: 0.00 AC: 0 AN: 60380

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Jan 28, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 1759 of the TSC2 protein (p.Ala1759Pro). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 951509). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TSC2 protein function. 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.067
BayesDel_addAF	Uncertain	0.094	D
BayesDel_noAF	Benign	-0.10
CADD	Benign	18
DANN	Benign	0.62
DEOGEN2	Benign	0.41	T
Eigen	Benign	-1.0
Eigen_PC	Benign	-0.98
FATHMM_MKL	Benign	0.019	N
LIST_S2	Benign	0.71	T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.14	T
MetaSVM	Benign	-0.56	T
MutationAssessor	Benign	0.0	N
PhyloP100		3.2
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-0.68	N
REVEL	Uncertain	0.49
Sift	Benign	0.31	T
Sift4G	Benign	0.18	T
Polyphen		0.0010	B
Vest4		0.20
MutPred		0.32		Gain of loop (P = 0.0097)
MVP		0.90
ClinPred		0.15	T
GERP RS		2.5
Varity_R		0.061
gMVP		0.50
Mutation Taster		=96/4	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.24		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.24		Position offset: 47

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs758450326; hg19: chr16-2138462;