16-2071864-G-A

Variant names:

• chr16-2071864-G-A
• rs754556513
• NM_000548.5:c.2027G>A

Variant summary

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

The NM_000548.5(TSC2):​c.2027G>A​(p.Gly676Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000753 in 1,328,766 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G676V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.5e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.10
• 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: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, 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 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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.2027G>A	p.Gly676Asp	missense	Exon 19 of 42	NP_000539.2	P49815-1
	TSC2	NM_001406663.1		c.2027G>A	p.Gly676Asp	missense	Exon 19 of 42	NP_001393592.1	A0A2R8Y6C9
	TSC2	NM_001114382.3		c.2027G>A	p.Gly676Asp	missense	Exon 19 of 41	NP_001107854.1	P49815-4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.2027G>A	p.Gly676Asp	missense	Exon 19 of 42	ENSP00000219476.3	P49815-1
	TSC2	ENST00000350773.9	TSL:1	c.2027G>A	p.Gly676Asp	missense	Exon 19 of 41	ENSP00000344383.4	P49815-4
	TSC2	ENST00000401874.7	TSL:1	c.2027G>A	p.Gly676Asp	missense	Exon 19 of 40	ENSP00000384468.2	P49815-5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.53e-7 AC: 1 AN: 1328766 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 651664

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

African (AFR) AF: 0.00 AC: 0 AN: 29548

American (AMR) AF: 0.00 AC: 0 AN: 29624

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 21298

East Asian (EAS) AF: 0.00 AC: 0 AN: 35406

South Asian (SAS) AF: 0.00 AC: 0 AN: 64590

European-Finnish (FIN) AF: 0.0000252 AC: 1 AN: 39664

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3830

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1049798

Other (OTH) AF: 0.00 AC: 0 AN: 55008

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.020
CADD	Benign	21
DANN	Benign	0.97
DEOGEN2	Uncertain	0.46	T
Eigen	Benign	-0.31
Eigen_PC	Benign	-0.21
FATHMM_MKL	Benign	0.44	N
LIST_S2	Uncertain	0.95	D
M_CAP	Uncertain	0.23	D
MetaRNN	Uncertain	0.51	D
MetaSVM	Benign	-0.51	T
MutationAssessor	Benign	0.69	N
PhyloP100		2.1
PrimateAI	Uncertain	0.51	T
PROVEAN	Benign	-0.93	N
REVEL	Uncertain	0.53
Sift	Benign	0.23	T
Sift4G	Benign	0.40	T
Polyphen		0.34	B
Vest4		0.44
MutPred		0.67		Loss of sheet (P = 0.0126)
MVP		0.98
ClinPred		0.38	T
GERP RS		4.4
Varity_R		0.051
gMVP		0.47
Mutation Taster		=90/10	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs754556513; hg19: chr16-2121865;