NM_000548.5:c.1443+5G>A

Variant names:

• chr16-2063058-G-A
• rs1057521562
• NM_000548.5:c.1443+5G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM2 PP3_Moderate BP6

The NM_000548.5(TSC2):​c.1443+5G>A variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000143 in 1,399,126 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TSC2 NM_000548.5 splice_region, intron
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 8.45
• Publications: 0 publications found

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]

TSC2 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
• lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• BP6: Variant 16-2063058-G-A is Benign according to our data. Variant chr16-2063058-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 383238.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.1443+5G>A		splice_region_variant, intron_variant	Intron 14 of 41	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1443+5G>A		splice_region_variant, intron_variant	Intron 14 of 41	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00 AC: 0 AN: 156192 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000143 AC: 2 AN: 1399126 Hom.: 0 Cov.: 31 AF XY: 0.00000290 AC XY: 2 AN XY: 690080

African (AFR) AF: 0.00 AC: 0 AN: 31594

American (AMR) AF: 0.00 AC: 0 AN: 35702

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25172

East Asian (EAS) AF: 0.0000280 AC: 1 AN: 35732

South Asian (SAS) AF: 0.00 AC: 0 AN: 79232

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49132

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 9.27e-7 AC: 1 AN: 1078882

Other (OTH) AF: 0.00 AC: 0 AN: 57990

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000251 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1 Benign:1

Nov 07, 2021

Genome-Nilou Lab

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 28, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 14 of the TSC2 gene. It does not directly change the encoded amino acid sequence of the TSC2 protein. It affects a nucleotide within the consensus splice site. 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: 383238). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant disrupts the c.1443+5 nucleotide in the TSC2 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 21520333, 29476190, 33391346). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. 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. -

Isolated focal cortical dysplasia type II Uncertain:1

Oct 17, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 21, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1443+5G>A intronic variant results from a G to A substitution 5 nucleotides after coding exon 13 in the TSC2 gene. This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis for this alteration is inconclusive. RNA studies have demonstrated that this alteration results in an incomplete splice defect; the clinical impact of this abnormal splicing is unknown at this time (Ambry internal data). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not provided Benign:1

Nov 15, 2019

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.39
CADD	Benign	19
DANN	Benign	0.66
PhyloP100		8.4
PromoterAI		-0.10	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.22		Position offset: -5

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

Other links and lift over

dbSNP: rs1057521562; hg19: chr16-2113059;