16-2084676-C-T

Position:

• chr16-2084676-C-T

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BP6 BS2

The NM_000548.5(TSC2):​c.4454C>T​(p.Thr1485Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000761 in 1,446,404 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign 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. T1485P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000076 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:2
• Conservation: PhyloP100: 2.90

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 -7 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.2029993).
• BP6: Variant 16-2084676-C-T is Benign according to our data. Variant chr16-2084676-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 535928.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Benign=1, Uncertain_significance=1}.
• BS2: High AC in GnomAdExome4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.4454C>T	p.Thr1485Ile	missense_variant	34/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.4454C>T	p.Thr1485Ile	missense_variant	34/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000126 AC: 3 AN: 237482 Hom.: 0 AF XY: 0.00000769 AC XY: 1 AN XY: 129978

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000654

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000167

GnomAD4 exome AF: 0.00000761 AC: 11 AN: 1446404 Hom.: 0 Cov.: 33 AF XY: 0.00000556 AC XY: 4 AN XY: 719970

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: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.0000332

GnomAD4 genome Cov.: 34

ExAC AF: 0.0000249 AC: 3

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 04, 2022

The p.T1485I variant (also known as c.4454C>T), located in coding exon 33 of the TSC2 gene, results from a C to T substitution at nucleotide position 4454. The threonine at codon 1485 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is conserved. 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. -

Tuberous sclerosis syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jul 22, 2023

- -

Tuberous sclerosis 2 Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Dec 30, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Uncertain	0.050	T
BayesDel_noAF	Uncertain	0.040
CADD	Benign	19
DANN	Benign	0.93
DEOGEN2	Uncertain	0.53	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.59
Eigen_PC	Benign	-0.50
FATHMM_MKL	Benign	0.68	D
LIST_S2	Uncertain	0.94	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.35	D
MetaRNN	Benign	0.20	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.36	T
MutationAssessor	Benign	0.0	N;.;.;.;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N
PrimateAI	Benign	0.31	T
PROVEAN	Benign	-1.7	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.49
Sift	Benign	0.15	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.19	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.21	B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.27
MutPred		0.32		Loss of glycosylation at T1485 (P = 0.0087);.;.;.;.;.;.;Loss of glycosylation at T1485 (P = 0.0087);.;.;.;.;.;.;.;
MVP		0.96
ClinPred		0.085	T
GERP RS		4.1
Varity_R		0.046
gMVP		0.35

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs772667717; hg19: chr16-2134677;