chr16-2050425-A-T

Variant names:

• chr16-2050425-A-T
• rs1555495709
• NM_000548.5:c.164A>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000548.5(TSC2):​c.164A>T​(p.Asn55Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict 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. N55S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 30)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.904
• 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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.29602265).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.164A>T	p.Asn55Ile	missense_variant	Exon 3 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.164A>T	p.Asn55Ile	missense_variant	Exon 3 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 30

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 07, 2019

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.N55I variant (also known as c.164A>T), located in coding exon 2 of the TSC2 gene, results from an A to T substitution at nucleotide position 164. The asparagine at codon 55 is replaced by isoleucine, an amino acid with dissimilar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Uncertain	0.043	T
BayesDel_noAF	Benign	-0.18
CADD	Benign	17
DANN	Benign	0.92
DEOGEN2	Uncertain	0.77	D;.;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.71
Eigen_PC	Benign	-0.65
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Benign	0.30	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.45	T
MutationAssessor	Benign	1.2	L;.;.;.;L;L;.;.;L;L;.;.;L;.;.;.
PhyloP100		0.90
PrimateAI	Benign	0.43	T
PROVEAN	Uncertain	-3.6	D;.;.;D;.;D;.;.;D;D;.;.;.;.;.;D
REVEL	Benign	0.23
Sift	Uncertain	0.020	D;.;.;D;.;D;.;.;D;D;.;.;.;.;.;D
Sift4G	Uncertain	0.014	D;.;.;D;.;D;.;.;D;D;.;.;.;.;.;D
Polyphen		0.17	B;.;.;.;.;B;.;.;P;B;.;.;.;.;.;.
Vest4		0.58
MutPred		0.39		Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);.;Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);Gain of helix (P = 0.0225);.;
MVP		0.76
ClinPred		0.89	D
GERP RS		2.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.23
gMVP		0.26
Mutation Taster		=69/31	polymorphism

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: rs1555495709; hg19: chr16-2100426;