NM_000391.4:c.1397T>G

Variant names:

• chr11-6615199-A-C
• rs398122959
• NM_000391.4:c.1397T>G

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PP5_Very_Strong

The NM_000391.4(TPP1):​c.1397T>G​(p.Val466Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,966 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V466M) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: TPP1 NM_000391.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 8.62
• Publications: 4 publications found

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]

TPP1 Gene-Disease associations (from GenCC):

• neuronal ceroid lipofuscinosis

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• neuronal ceroid lipofuscinosis 2

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Myriad Women’s Health, G2P, Orphanet
• autosomal recessive spinocerebellar ataxia 7

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000285338 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_000391.4
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-6615199-A-C is Pathogenic according to our data. Variant chr11-6615199-A-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 89086.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPP1	NM_000391.4	c.1397T>G	p.Val466Gly	missense_variant	Exon 11 of 13	ENST00000299427.12	NP_000382.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPP1	ENST00000299427.12	c.1397T>G	p.Val466Gly	missense_variant	Exon 11 of 13	1	NM_000391.4	ENSP00000299427.6

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152074 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251488 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461892 Hom.: 0 Cov.: 34 AF XY: 0.00000413 AC XY: 3 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 152074 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74276

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41368

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68010

Other (OTH) AF: 0.00 AC: 0 AN: 2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.0000431 Hom.: 0

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:5

Jan 10, 2023

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 23775425, 34733232, 31059981, 31283065, 23418007) -

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Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 22, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 466 of the TPP1 protein (p.Val466Gly). This variant is present in population databases (rs398122959, gnomAD 0.002%). This missense change has been observed in individual(s) with autosomal recessive spinocerebellar ataxia (PMID: 23418007). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 89086). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on TPP1 protein function. For these reasons, this variant has been classified as Pathogenic. -

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Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Autosomal recessive spinocerebellar ataxia 7 Pathogenic:1

May 01, 2013

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.41	T;.;.;.;.;.;.
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.68	T;.;T;.;T;.;T
M_CAP	Pathogenic	0.61	D
MetaRNN	Uncertain	0.52	D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.067	T
MutationAssessor	Benign	1.5	L;.;.;.;.;.;.
PhyloP100		8.6
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-2.1	N;N;.;.;.;.;.
REVEL	Uncertain	0.49
Sift	Benign	0.077	T;T;.;.;.;.;.
Sift4G	Benign	0.11	T;T;.;.;.;.;.
Polyphen		0.75	P;.;.;.;.;.;.
Vest4		0.78
MutPred		0.47		Loss of stability (P = 0.0012);.;.;.;.;.;.;
MVP		0.96
MPC		0.30
ClinPred		0.68	D
GERP RS		5.3
Varity_R		0.33
gMVP		0.84
Mutation Taster		=11/89	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
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

Other links and lift over

dbSNP: rs398122959; hg19: chr11-6636430;