NM_000548.5:c.1991C>T

Variant names:

• chr16-2071828-C-T
• rs991714565
• NM_000548.5:c.1991C>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM2 PP3_Moderate BP6

The NM_000548.5(TSC2):​c.1991C>T​(p.Ser664Phe) variant causes a missense change. The variant allele was found at a frequency of 0.000000692 in 1,445,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S664Y) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 5.63
• Publications: 1 publications found

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]

TSC2 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
• lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.846
• BP6: Variant 16-2071828-C-T is Benign according to our data. Variant chr16-2071828-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 647861.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000548.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.1991C>T	p.Ser664Phe	missense	Exon 19 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.1991C>T	p.Ser664Phe	missense	Exon 19 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.1991C>T	p.Ser664Phe	missense	Exon 19 of 41	NP_001107854.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.1991C>T	p.Ser664Phe	missense	Exon 19 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.1991C>T	p.Ser664Phe	missense	Exon 19 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.1991C>T	p.Ser664Phe	missense	Exon 19 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000468 AC: 1 AN: 213650 AF XY: 0.00000852

Gnomad AFR exome AF: 0.0000824

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.92e-7 AC: 1 AN: 1445894 Hom.: 0 Cov.: 32 AF XY: 0.00000139 AC XY: 1 AN XY: 717852

African (AFR) AF: 0.0000302 AC: 1 AN: 33116

American (AMR) AF: 0.00 AC: 0 AN: 43228

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25716

East Asian (EAS) AF: 0.00 AC: 0 AN: 38964

South Asian (SAS) AF: 0.00 AC: 0 AN: 83612

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50850

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1104974

Other (OTH) AF: 0.00 AC: 0 AN: 59690

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1 Benign:1

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Dec 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Uncertain:1

Dec 08, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Hereditary cancer-predisposing syndrome Uncertain:1

Jun 06, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.S664F variant (also known as c.1991C>T), located in coding exon 18 of the TSC2 gene, results from a C to T substitution at nucleotide position 1991. The serine at codon 664 is replaced by phenylalanine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.46
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.34
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.35	D
MetaRNN	Pathogenic	0.85	D
MetaSVM	Uncertain	0.78	D
MutationAssessor	Uncertain	2.4	M
PhyloP100		5.6
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-3.6	D
REVEL	Pathogenic	0.68
Sift	Uncertain	0.0050	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.68
MutPred		0.37		Loss of phosphorylation at S664 (P = 0.0069)
MVP		0.91
ClinPred		0.95	D
GERP RS		5.5
Varity_R		0.38
gMVP		0.60
Mutation Taster		=53/47	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs991714565; hg19: chr16-2121829;