16-2087897-CG-TC

Variant names:

• chr16-2087897-CG-TC
• NM_000548.5:c.5024_5025delCGinsTC
• TSC2 p.Pro1675Leu

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PS1_Very_Strong PM1 PM5 PP3

The NM_000548.5(TSC2):​c.5024_5025delCGinsTC​(p.Pro1675Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P1675R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.84
• Publications: 0 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: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, 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: Pathogenic. The variant received 13 ACMG points.

• PS1: Transcript NM_000548.5 (TSC2) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 15 benign, 40 uncertain in NM_000548.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-2087897-C-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1697094.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.5024_5025delCGinsTC	p.Pro1675Leu	missense	N/A	NP_000539.2	P49815-1
	TSC2	NM_001406663.1		c.5021_5022delCGinsTC	p.Pro1674Leu	missense	N/A	NP_001393592.1	A0A2R8Y6C9
	TSC2	NM_001114382.3		c.4955_4956delCGinsTC	p.Pro1652Leu	missense	N/A	NP_001107854.1	P49815-4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.5024_5025delCGinsTC	p.Pro1675Leu	missense	N/A	ENSP00000219476.3	P49815-1
	TSC2	ENST00000350773.9	TSL:1	c.4955_4956delCGinsTC	p.Pro1652Leu	missense	N/A	ENSP00000344383.4	P49815-4
	TSC2	ENST00000401874.7	TSL:1	c.4823_4824delCGinsTC	p.Pro1608Leu	missense	N/A	ENSP00000384468.2	P49815-5

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.8

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr16-2137898;