16-2086732-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PM5

The NM_000548.5(TSC2):​c.4850C>T​(p.Ala1617Val) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. A1617P) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

TSC2
NM_000548.5 missense, splice_region

Scores

1
9
9
Splicing: ADA: 0.009565
2

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.96
Variant links:
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]

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM1
In a domain Rap-GAP (size 227) in uniprot entity TSC2_HUMAN there are 284 pathogenic changes around while only 47 benign (86%) in NM_000548.5
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr16-2086379-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
TSC2NM_000548.5 linkuse as main transcriptc.4850C>T p.Ala1617Val missense_variant, splice_region_variant 38/42 ENST00000219476.9 NP_000539.2

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
TSC2ENST00000219476.9 linkuse as main transcriptc.4850C>T p.Ala1617Val missense_variant, splice_region_variant 38/425 NM_000548.5 ENSP00000219476 P49815-1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
Data not reliable, filtered out with message: AC0
AF:
0.00
AC:
0
AN:
1457474
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
725058
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:
0.00
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
LINK: link

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpJan 24, 2024This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1617 of the TSC2 protein (p.Ala1617Val). 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: 1519622). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -
Hereditary cancer-predisposing syndrome Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingAmbry GeneticsNov 05, 2021The p.A1617V variant (also known as c.4850C>T) is located in coding exon 37 of the TSC2 gene. The alanine at codon 1617 is replaced by valine, an amino acid with similar properties. This change occurs in the first base pair of coding exon 37. This amino acid position is well 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
0.25
BayesDel_addAF
Pathogenic
0.21
D
BayesDel_noAF
Uncertain
0.060
CADD
Uncertain
24
DANN
Benign
0.82
DEOGEN2
Uncertain
0.51
D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen
Benign
0.053
Eigen_PC
Benign
0.14
FATHMM_MKL
Uncertain
0.93
D
LIST_S2
Uncertain
0.95
D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP
Uncertain
0.29
D
MetaRNN
Uncertain
0.54
D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM
Uncertain
0.15
D
MutationAssessor
Benign
-0.93
N;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster
Benign
1.0
D;D;D;D;D;D;D
PrimateAI
Uncertain
0.71
T
PROVEAN
Benign
0.57
N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL
Uncertain
0.61
Sift
Benign
0.76
T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G
Benign
0.82
T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen
0.92
P;.;.;.;P;P;.;.;D;P;.;.;.;.;.
Vest4
0.56
MutPred
0.53
Gain of sheet (P = 0.0266);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP
0.89
ClinPred
0.72
D
GERP RS
5.0
Varity_R
0.25
gMVP
0.64

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Benign
0.0096
dbscSNV1_RF
Benign
0.22
SpliceAI score (max)
0.050
Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-2136733; API