rs760885994

chr16-2072950-C-Gchr16-2072950-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000548.5(TSC2):c.2322C>G(p.Ile774Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,236 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I774I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.140

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.2322C>G	p.Ile774Met	missense_variant	21/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.2322C>G	p.Ile774Met	missense_variant	21/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461236 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726892

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 24, 2021

The p.I774M variant (also known as c.2322C>G), located in coding exon 20 of the TSC2 gene, results from a C to G substitution at nucleotide position 2322. The isoleucine at codon 774 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
Cadd	Benign	21
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.56	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.15
FATHMM_MKL	Benign	0.73	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Uncertain	0.46	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.40	D
MutationAssessor	Benign	1.7	L;.;.;.;L;L;.;.;.;L;.;L;.;.;.
MutationTaster	Benign	0.84	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.57	T
PROVEAN	Benign	-1.0	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.58
Sift	Uncertain	0.025	D;.;.;T;.;T;.;.;T;D;.;.;.;.;T
Sift4G	Benign	0.083	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		1.0	D;.;.;.;D;D;.;.;D;D;.;.;.;.;.
Vest4		0.76
MutPred		0.68		Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);.;Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);.;Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);Gain of helix (P = 0.2059);.;
MVP		0.85
ClinPred		0.79	D
GERP RS		2.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.17
gMVP		0.45

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: rs760885994; hg19: chr16-2122951;