16-2048010-G-C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_000548.5(TSC2):c.-85G>C variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000266 in 1,476,304 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00014 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00028 (4 hom.)
• Consequence: TSC2 NM_000548.5 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.957

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 Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.68).
• BS1: Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.00028 (371/1323992) while in subpopulation EAS AF= 0.0101 (336/33158). AF 95% confidence interval is 0.00924. There are 4 homozygotes in gnomad4_exome. There are 189 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd at 22 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.-85G>C		5_prime_UTR_variant	1/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.-85G>C		5_prime_UTR_variant	1/42	5	NM_000548.5

Frequencies

GnomAD3 genomes AF: 0.000145 AC: 22 AN: 152200 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00289

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.000478

GnomAD4 exome AF: 0.000280 AC: 371 AN: 1323992 Hom.: 4 Cov.: 31 AF XY: 0.000292 AC XY: 189 AN XY: 647886

Gnomad4 AFR exome AF: 0.0000361

Gnomad4 AMR exome AF: 0.000106

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0101

Gnomad4 SAS exome AF: 0.0000423

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000191

Gnomad4 OTH exome AF: 0.000145

GnomAD4 genome AF: 0.000144 AC: 22 AN: 152312 Hom.: 0 Cov.: 32 AF XY: 0.000188 AC XY: 14 AN XY: 74472

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00290

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.000108 Hom.: 0

Bravo AF: 0.000106

Asia WGS AF: 0.00144 AC: 5 AN: 3476

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
Cadd	Benign	14
Dann	Benign	0.70

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: rs540716235; hg19: chr16-2098011;