rs796053480

Positions:

• chr16-2088576-TCTC-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PM4_Supporting BS2

The NM_000548.5(TSC2):​c.5394_5396del​(p.Ser1799del) variant causes a inframe deletion change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000087 in 1,608,830 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: TSC2 NM_000548.5 inframe_deletion
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 7.73

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 -3 ACMG points.

• PM4: Nonframeshift variant in NON repetitive region in NM_000548.5. Strenght limited to Supporting due to length of the change: 1aa.
• BS2: High AC in GnomAdExome4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.5394_5396del	p.Ser1799del	inframe_deletion	42/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.5394_5396del	p.Ser1799del	inframe_deletion	42/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152154 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.000478

GnomAD3 exomes AF: 0.0000122 AC: 3 AN: 245802 Hom.: 0 AF XY: 0.00000747 AC XY: 1 AN XY: 133802

Gnomad AFR exome AF: 0.0000627

Gnomad AMR exome AF: 0.00

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: 0.0000179

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000824 AC: 12 AN: 1456676 Hom.: 0 AF XY: 0.00000552 AC XY: 4 AN XY: 724872

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000206

Gnomad4 NFE exome AF: 0.00000630

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152154 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74322

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

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: 0.000478

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000227

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Sep 09, 2021

The TSC2 c.5394_5396del (p.Ser1799del) change has a maximum subpopulation frequency of 0.0041% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/16-2138577-TCTC-T). The change results in the deletion of a single serine residue in a region without a known function at the c-terminal end of the gene (BP3). To our knowledge, functional studies have not been performed. This variant has been reported in a woman with lymphangioleiomyomatosis (PMID: 31856217). In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria: BP3. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 17, 2022

In-frame deletion of 1 amino acid in a non-repeat region; Previously reported as a variant of uncertain significance in a woman with a clinical diagnosis of tuberous sclerosis and lymphangioleiomyomatosis (Liu et al., 2019); In silico analysis supports a deleterious effect on protein structure/function; Published functional studies demonstrate reduced levels of TSC1 and TSC2 protein and elevated levels of phosphorylated AKT (Mrozek et al., 2021); This variant is associated with the following publications: (PMID: 31856217, 33891611) -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 01, 2023

The c.5394_5396delCTC (p.S1799del) alteration is located in exon 42 (coding exon 41) of the TSC2 gene. This alteration consists of an in-frame deletion of 3 nucleotides between nucleotide positions c.5394 and c.5396, resulting in the deletion of 1 residue. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Tuberous sclerosis 2 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 01, 2023

- -

Computational scores

Source: dbNSFP v4.3

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: rs796053480; hg19: chr16-2138577;