16-2070578-G-C

Variant names:

• chr16-2070578-G-C
• rs1555505208
• NM_000548.5:c.1839G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_000548.5(TSC2):​c.1839G>C​(p.Gln613His) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.92

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_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 16-2070578-G-C is Pathogenic according to our data. Variant chr16-2070578-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 467902.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr16-2070578-G-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.1839G>C	p.Gln613His	missense_variant, splice_region_variant	Exon 17 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.1839G>C	p.Gln613His	missense_variant, splice_region_variant	Exon 17 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:1

May 12, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine with histidine at codon 613 of the TSC2 protein (p.Gln613His). The glutamine residue is highly conserved and there is a small physicochemical difference between glutamine and histidine. This variant also falls at the last nucleotide of exon 17, which is part of the consensus splice site for this exon. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with tuberous sclerosis complex (Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 467902). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). Nucleotide substitutions within 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, but this prediction has not been confirmed by published transcriptional studies. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	36
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.77	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.46	D
MutationAssessor	Uncertain	2.0	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-2.5	N;.;.;D;.;D;.;.;D;N;.;.;.;.;D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.029	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Benign	0.090	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		1.0	D;.;.;.;P;P;.;.;P;P;.;.;.;.;.
Vest4		0.70
MutPred		0.66		Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);.;Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);.;Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);.;
MVP		0.89
ClinPred		0.91	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.27
gMVP		0.68

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.63		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.63		Position offset: 46
DS_DL_spliceai		0.26		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555505208; hg19: chr16-2120579;