NM_000391.4:c.1280C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM1BP4_ModerateBP6

The NM_000391.4(TPP1):c.1280C>T(p.Thr427Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000112 in 1,614,070 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 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. T427S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00022 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00010 ( 0 hom. )

Consequence

TPP1
NM_000391.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1

Conservation

PhyloP100: 1.79

Publications

5 publications found

Variant links:

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

TPP1 links:

ENSG00000285338 (HGNC:):

ENSG00000285338 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000391.4

BP4

Computational evidence support a benign effect (MetaRNN=0.10267934).

BP6

Variant 11-6615316-G-A is Benign according to our data. Variant chr11-6615316-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 207590.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPP1	NM_000391.4 link	c.1280C>T	p.Thr427Met	missense_variant	Exon 11 of 13	ENST00000299427.12	NP_000382.3	O14773-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPP1	ENST00000299427.12 link	c.1280C>T	p.Thr427Met	missense_variant	Exon 11 of 13	1	NM_000391.4	ENSP00000299427.6		O14773-1

Frequencies

GnomAD3 genomes

AF:

0.000223

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000410

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000220

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000171

AC:

AN:

251438

AF XY:

0.000162

show subpopulations

Gnomad AFR exome

AF:

0.000308

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.0000992

Gnomad EAS exome

AF:

0.000109

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.000237

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000999

AC:

146

AN:

1461890

Hom.:

Cov.:

AF XY:

0.000100

AC XY:

AN XY:

727246

show subpopulations

African (AFR)

AF:

0.000239

AC:

AN:

33480

American (AMR)

AF:

0.000134

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.000151

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000562

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.000347

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000845

AC:

AN:

1112010

Other (OTH)

AF:

0.000447

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000223

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.000242

AC XY:

AN XY:

74342

show subpopulations

African (AFR)

AF:

0.000410

AC:

AN:

41424

American (AMR)

AF:

0.0000654

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000192

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000220

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.515

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000208

Hom.:

Bravo

AF:

0.000189

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.000454

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000198

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Aug 13, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis suggests that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Dec 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Uncertain:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Uncertain:1

Dec 03, 2018

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.T427M variant (also known as c.1280C>T), located in coding exon 11 of the TPP1 gene, results from a C to T substitution at nucleotide position 1280. The threonine at codon 427 is replaced by methionine, an amino acid with similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Intellectual disability

Uncertain:1

Jan 01, 2019

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.30

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.37

T;.;.;.;.;.;.

Eigen

Benign

-0.045

Eigen_PC

Benign

-0.035

FATHMM_MKL

Benign

0.16

LIST_S2

Benign

0.72

T;.;T;.;T;.;T

M_CAP

Benign

0.075

MetaRNN

Benign

0.10

T;T;T;T;T;T;T

MetaSVM

Uncertain

-0.23

MutationAssessor

Benign

1.5

L;.;.;.;.;.;.

PhyloP100

1.8

PrimateAI

Benign

0.32

PROVEAN

Benign

-1.4

N;N;.;.;.;.;.

REVEL

Benign

0.25

Sift

Benign

0.097

T;D;.;.;.;.;.

Sift4G

Uncertain

0.028

D;D;.;.;.;.;.

Polyphen

0.91

P;.;.;.;.;.;.

Vest4

0.23

MVP

0.93

MPC

0.36

ClinPred

0.020

GERP RS

4.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.046

gMVP

0.52

Mutation Taster

=88/12

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over