rs45443091

Positions:

• chr16-2062586-G-A
• chr16-2062586-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000548.5(TSC2):​c.1347G>A​(p.Met449Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,456,928 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 nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M449K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.59

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.845

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.1347G>A	p.Met449Ile	missense_variant	13/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.1347G>A	p.Met449Ile	missense_variant	13/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1456928 Hom.: 0 Cov.: 31 AF XY: 0.00000414 AC XY: 3 AN XY: 724180

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000352

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 30, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 10, 2023	This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 449 of the TSC2 protein (p.Met449Ile). 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: 852892). 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 v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.50	T;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.30
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-0.41	T
MutationAssessor	Benign	1.8	L;.;.;.;L;L;.;.;.;L;.;L;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Benign	-1.9	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.57
Sift	Benign	0.081	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.074	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.89	P;.;.;.;B;P;.;.;B;B;.;.;.;.;.
Vest4		0.91
MutPred		0.79		Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);.;Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);.;Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);Loss of MoRF binding (P = 0.1019);.;
MVP		0.95
ClinPred		0.91	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.46
gMVP		0.71

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

Publications

LitVar

Other links and lift over

dbSNP: rs45443091; hg19: chr16-2112587;