rs1554902216

Positions:

• chr11-6618819-CGA-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000391.4(TPP1):​c.184_185del​(p.Ser62GlyfsTer25) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. S62S) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TPP1 NM_000391.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.992

Genes affected

TPP1 (HGNC:2073): (tripeptidyl peptidase 1) This gene encodes a member of the sedolisin family of serine proteases. The protease functions in the lysosome to cleave N-terminal tripeptides from substrates, and has weaker endopeptidase activity. It is synthesized as a catalytically-inactive enzyme which is activated and auto-proteolyzed upon acidification. Mutations in this gene result in late-infantile neuronal ceroid lipofuscinosis, which is associated with the failure to degrade specific neuropeptides and a subunit of ATP synthase in the lysosome. [provided by RefSeq, Jul 2008]

(HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-6618819-CGA-C is Pathogenic according to our data. Variant chr11-6618819-CGA-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 552025.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TPP1	NM_000391.4	c.184_185del	p.Ser62GlyfsTer25	frameshift_variant	3/13	ENST00000299427.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TPP1	ENST00000299427.12	c.184_185del	p.Ser62GlyfsTer25	frameshift_variant	3/13	1	NM_000391.4	P1
	ENST00000545572.1	n.34_35del		non_coding_transcript_exon_variant	1/2	3

Frequencies

GnomAD3 genomes Cov.: 32

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

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neuronal ceroid lipofuscinosis Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 01, 2023	Variant summary: TPP1 c.184_185delTC (p.Ser62GlyfsX25) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 251362 control chromosomes. c.184_185delTC has been reported in the literature in at-least one individual affected with Neuronal Ceroid-Lipofuscinosis (Batten Disease) (example, Lam_2001). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 14, 2023

This sequence change creates a premature translational stop signal (p.Ser62Glyfs*25) in the TPP1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TPP1 are known to be pathogenic (PMID: 10330339). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with neuronal ceroid lipofuscinosis (PMID: 11241479). This variant is also known as 1902delCT. ClinVar contains an entry for this variant (Variation ID: 552025). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Neuronal ceroid lipofuscinosis 2 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

May 19, 2017

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.16		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: rs1554902216; hg19: chr11-6640050;