rs756564767

chr11-6617627-G-A

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.379C>T(p.Arg127Ter) variant causes a stop gained, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000508 in 1,613,930 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000052 (0 hom.)
• Consequence: TPP1 NM_000391.4 stop_gained, splice_region
• Scores: Splicing: ADA: 0.7899
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 0.275

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]

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 11-6617627-G-A is Pathogenic according to our data. Variant chr11-6617627-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 207569.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-6617627-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TPP1	NM_000391.4	c.379C>T	p.Arg127Ter	stop_gained, splice_region_variant	4/13	ENST00000299427.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TPP1	ENST00000299427.12	c.379C>T	p.Arg127Ter	stop_gained, splice_region_variant	4/13	1	NM_000391.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152100 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000636 AC: 16 AN: 251478 Hom.: 0 AF XY: 0.0000662 AC XY: 9 AN XY: 135916

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.000347

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000520 AC: 76 AN: 1461830 Hom.: 0 Cov.: 33 AF XY: 0.0000495 AC XY: 36 AN XY: 727214

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.000313

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000513

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152100 Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3 AN XY: 74284

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000160 Hom.: 0

Bravo AF: 0.0000302

ExAC AF: 0.0000412 AC: 5

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neuronal ceroid lipofuscinosis 2 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	May 02, 2018	The TPP1 c.379C>T p.(Arg127Ter) variant is nonsense variant is expected to result in the loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. This variant has been identified in individuals with a phenotype consistent with late infantile-onset NCL or undiagnosed lysosomal storage disorder (Sleat et al. 1999; Sleat et al. 2009; Di Fruscio et al. 2015). The highest frequency of this allele in the Genome Aggregation Database is 0.000032 in the Latino population (version 2.1.1). Functional studies of the variant have not been conducted, but deficient enzyme activity and protein expression were demonstrated in fibroblasts and post-mortem brain tissue from the compound heterozygous individuals. Based on the available evidence, the c.379C>T (p.(Arg127Ter) variant is classified as pathogenic for neuronal ceroid lipofuscinosis. -
Pathogenic, criteria provided, single submitter	research	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Dec 03, 2018	The homozygous p.Arg127Ter variant in TPP1 was identified by our study in one individual with Neuronal Ceroid Lipofuscinosis. The p.Arg127Ter variant in TPP has been reported in 8 individuals from Turkey, Mexico, US, German, UK, and Canada, with Neuronal Ceroid Lipofuscinosis, segregated with disease in 3 affected relatives from 1 families (PMID: 10330339, 21990111), and has been identified in 0.03196% (11/34420) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs756564767). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported pathogenic in ClinVar (Variation ID: 207569). This nonsense variant leads to a premature termination codon at position 127, which is predicted to lead to a truncated or absent protein. Loss of function of the TPP1 gene is an established disease mechanism in autosomal recessive Neuronal Ceroid Lipofuscinosis. The presence of this variant in combination with a reported pathogenic variant as well as a splice site variant absent from ClinVar, and in 3 individuals with Neuronal Ceroid Lipofuscinosis increases the likelihood that the p.Arg127Ter variant is pathogenic (PMID: 10330339, 21990111; Variation ID: 2643). In summary, this variant meets criteria to be classified as pathogenic for Neuronal Ceroid Lipofuscinosis in an autosomal recessive manner based on the predicted impact of the variant and multiple occurrences with pathogenic TPP1 variants in individuals with Neuronal Ceroid Lipofuscinosis. ACMG/AMP Criteria applied: PM2, PVS1, PM3, PP1 (Richards 2015). -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 29, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 15, 2022	Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 25525159, 26075876, 29631617, 28289221, 10330339, 21990111, 30792901, 31589614) -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Nov 30, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 10, 2024	This sequence change creates a premature translational stop signal (p.Arg127*) 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 present in population databases (rs756564767, gnomAD 0.03%). This premature translational stop signal has been observed in individual(s) with autosomal recessive neuronal ceroid lipofucinosis (PMID: 10330339). ClinVar contains an entry for this variant (Variation ID: 207569). For these reasons, this variant has been classified as Pathogenic. -

Autosomal recessive spinocerebellar ataxia 7;C1876161:Neuronal ceroid lipofuscinosis 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Angelman syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India

-

- -

Neuronal ceroid lipofuscinosis Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Aug 05, 2019

Variant summary: TPP1 c.379C>T (p.Arg127X) 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. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 6.4e-05 in 251478 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in TPP1 causing Neuronal Ceroid-Lipofuscinosis (Batten Disease) (6.4e-05 vs 0.003), allowing no conclusion about variant significance. c.379C>T has been reported in the literature in at-least two individuals affected with Neuronal Ceroid-Lipofuscinosis (Batten Disease)(Sleat_1999, Scocchia_2019). These data indicate that the variant is likely to be associated with disease. 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. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.48
Cadd	Pathogenic	37
Dann	Uncertain	1.0
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Benign	0.71	D
MutationTaster	Benign	1.0	A;D
Vest4		0.76
GERP RS		3.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.79
dbscSNV1_RF	Benign	0.46
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: rs756564767; hg19: chr11-6638858; COSMIC: COSV54993759; COSMIC: COSV54993759;