16-2071506-A-G

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_000548.5(TSC2):c.1840-4A>G variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,264 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.001725
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: -0.779

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.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BP6: Variant 16-2071506-A-G is Benign according to our data. Variant chr16-2071506-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 390347.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=1, Benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.1840-4A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.1840-4A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249862 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135522

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461264 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726942

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Invitae	Jul 30, 2023	- -

Lymphangiomyomatosis;C1846385:Isolated focal cortical dysplasia type II;C1860707:Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Jul 21, 2021

TSC2 NM_000548.3 intron 17 c.1840-4A>G:This variant has not been reported in the literature and is not present in large control databases. This variant is present in ClinVar (Variation ID:390347). Evolutionary conservation and computational predictive tools for this variant are limited or unavailable. Although this variant occurs in the splice region, computational prediction tools do not suggest that it alters splicing. However, further studies are needed to understand its impact. In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain. -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Oct 26, 2016

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. -

Tuberous sclerosis syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Apr 10, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
Cadd	Benign	1.4
Dann	Benign	0.51

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.0017
dbscSNV1_RF	Benign	0.18
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: rs1057523736; hg19: chr16-2121507;