rs757113497

Positions:

• chr16-2048721-A-G
• chr16-2048721-A-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_000548.5(TSC2):​c.106A>G​(p.Thr36Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,936 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T36M) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:3
• Conservation: PhyloP100: 3.32

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17793036).
• BP6: Variant 16-2048721-A-G is Benign according to our data. Variant chr16-2048721-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 207655.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.106A>G	p.Thr36Ala	missense_variant	2/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.106A>G	p.Thr36Ala	missense_variant	2/42	5	NM_000548.5

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152172 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251284 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135894

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461764 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727168

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152172 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74348

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000227

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Invitae	Oct 27, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	Jun 22, 2023	The TSC2 c.106A>G (p.Thr36Ala) missense change has a maximum subpopulation frequency of 0.0058% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org). The in silico tool REVEL predicts a benign effect on protein function, but to our knowledge this prediction has not been confirmed by functional studies. To our knowledge, this variant has not been reported in individuals with tuberous sclerosis complex. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 25, 2021

The p.T36A variant (also known as c.106A>G), located in coding exon 1 of the TSC2 gene, results from an A to G substitution at nucleotide position 106. The threonine at codon 36 is replaced by alanine, an amino acid with similar properties. 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. -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Apr 03, 2013

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.092
BayesDel_addAF	Benign	-0.018	T
BayesDel_noAF	Benign	-0.090
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.47	T;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.25
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.91	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.092	D
MetaRNN	Benign	0.18	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.49	T
MutationAssessor	Benign	1.6	L;.;.;L;L;.;.;L;L;.;.;L;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-1.5	N;.;.;.;N;.;.;N;N;.;.;.;.;.;N
REVEL	Benign	0.23
Sift	Benign	0.23	T;.;.;.;T;.;.;T;T;.;.;.;.;.;T
Sift4G	Benign	0.42	T;.;.;.;T;.;.;T;T;.;.;.;.;.;T
Polyphen		0.98	D;.;.;.;D;.;.;P;B;.;.;.;.;.;.
Vest4		0.55
MutPred		0.30		Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);Loss of sheet (P = 0.0084);.;
MVP		0.89
ClinPred		0.59	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.095
gMVP		0.13

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: rs757113497; hg19: chr16-2098722;