16-2055505-C-A

Variant names:

• chr16-2055505-C-A
• rs397515309
• NM_000548.5:c.585C>A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000548.5(TSC2):​c.585C>A​(p.Ile195Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I195I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TSC2 NM_000548.5 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: -0.209

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.585C>A	p.Ile195Ile	synonymous_variant	Exon 6 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.585C>A	p.Ile195Ile	synonymous_variant	Exon 6 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Aug 09, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TSC2 c.585C>A alters a non-conserved nucleotide resulting in a synonymous change. Consensus agreement among computation tools predict no significant impact on normal splicing. At least one publication reports experimental evidence that this variant affects mRNA splicing. The variant was absent in 251492 control chromosomes. c.585C>A has been reported in the literature in a family with multiple members affected with Tuberous Sclerosis Complex with no family pedigree to determine segregation (Ng_2022). These data do not allow any conclusion about variant significance. A functional study assessed the effect of this variant on splicing and the result showed skipping of exon 6, leading to a reading frame shift and a premature termination (Ng_2022). ClinVar contains an entry for this variant (Variation ID: 65051). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Tuberous sclerosis syndrome Other:1

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Tuberous sclerosis database (TSC2)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.34
CADD	Benign	0.48
DANN	Benign	0.69

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.52		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.52		Position offset: 14

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

Publications

LitVar

Other links and lift over

dbSNP: rs397515309; hg19: chr16-2105506;