rs1555440757

Variant names:

• chr16-2088303-A-ACAT
• rs1555440757
• NM_000548.5:c.5240_5242dupTCA

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PM4_Supporting

The NM_000548.5(TSC2):​c.5240_5242dupTCA​(p.Ile1747dup) variant causes a disruptive inframe insertion change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 34)
• Consequence: TSC2 NM_000548.5 disruptive_inframe_insertion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.869

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 Uncertain_significance. Variant got 5 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
• PM4: Nonframeshift variant in NON repetitive region in NM_000548.5. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.5240_5242dupTCA	p.Ile1747dup	disruptive_inframe_insertion	Exon 41 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.5240_5242dupTCA	p.Ile1747dup	disruptive_inframe_insertion	Exon 41 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Mar 11, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this is a novel in-frame duplication with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Experimental studies and prediction algorithms are not available for this variant, and the functional significance of the duplicated amino acid is currently unknown. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TSC2-related disease. This sequence change inserts 3 nucleotides in exon 41 of the TSC2 mRNA (c.5240_5242dupTCA). This leads to the insertion of 1 amino acid residue in the TSC2 protein (p.Ile1747dup) but otherwise preserves the integrity of the reading frame. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555440757; hg19: chr16-2138304;