16-2075870-C-G

Variant names:

• chr16-2075870-C-G
• rs1555508418
• NM_000548.5:c.2617C>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000548.5(TSC2):​c.2617C>G​(p.Leu873Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,228 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. L873P) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.22
• Publications: 0 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]

TSC2 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
• lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 6 benign, 33 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.779

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.2617C>G	p.Leu873Val	missense	Exon 23 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.2617C>G	p.Leu873Val	missense	Exon 23 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.2617C>G	p.Leu873Val	missense	Exon 23 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.2617C>G	p.Leu873Val	missense	Exon 23 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.2617C>G	p.Leu873Val	missense	Exon 23 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.2617C>G	p.Leu873Val	missense	Exon 23 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152228 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

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: 0.0000941

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 33

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152228 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74372

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41458

American (AMR) AF: 0.00 AC: 0 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.0000941 AC: 1 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68038

Other (OTH) AF: 0.00 AC: 0 AN: 2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Hereditary cancer-predisposing syndrome (1)
-	1	-	Tuberous sclerosis 2 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D
Eigen	Uncertain	0.27
Eigen_PC	Benign	0.22
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.78	D
MetaSVM	Uncertain	0.43	D
MutationAssessor	Uncertain	2.0	M
PhyloP100		3.2
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-2.3	N
REVEL	Pathogenic	0.79
Sift	Benign	0.12	T
Sift4G	Uncertain	0.0080	D
Polyphen		0.99	D
Vest4		0.79
MutPred		0.69		Gain of sheet (P = 0.0477)
MVP		0.96
ClinPred		0.92	D
GERP RS		3.1
Varity_R		0.24
gMVP		0.63
Mutation Taster		=41/59	disease causing

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

Other links and lift over

dbSNP: rs1555508418; hg19: chr16-2125871;