chr16-2079598-C-A

Variant names:

• chr16-2079598-C-A
• rs796053474
• NM_000548.5:c.3326C>A

Variant summary

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

The NM_000548.5(TSC2):​c.3326C>A​(p.Pro1109Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. P1109A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.22
• 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 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.3326C>A	p.Pro1109Gln	missense	Exon 29 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.3323C>A	p.Pro1108Gln	missense	Exon 29 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.3326C>A	p.Pro1109Gln	missense	Exon 29 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.3326C>A	p.Pro1109Gln	missense	Exon 29 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.3326C>A	p.Pro1109Gln	missense	Exon 29 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.3194C>A	p.Pro1065Gln	missense	Exon 28 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Feb 28, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.P1109Q variant (also known as c.3326C>A), located in coding exon 28 of the TSC2 gene, results from a C to A substitution at nucleotide position 3326. The proline at codon 1109 is replaced by glutamine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.52
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.70	D
Eigen	Uncertain	0.54
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.67	D
MetaRNN	Uncertain	0.72	D
MetaSVM	Uncertain	0.47	D
MutationAssessor	Uncertain	2.3	M
PhyloP100		7.2
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.3	D
REVEL	Uncertain	0.55
Sift	Benign	0.24	T
Sift4G	Benign	0.16	T
Polyphen		1.0	D
Vest4		0.72
MutPred		0.17		Gain of helix (P = 0.0082)
MVP		0.85
ClinPred		0.99	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.21
gMVP		0.51
Mutation Taster		=13/87	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.20		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.20		Position offset: -41

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

Other links and lift over

dbSNP: rs796053474; hg19: chr16-2129599;