rs1338658857

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PP2PP3_StrongPP5

The NM_000271.5(NPC1):c.3281T>C(p.Ile1094Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:3

Conservation

PhyloP100: 9.32

Publications

6 publications found

Variant links:

Genes affected

NPC1 (HGNC:7897): (NPC intracellular cholesterol transporter 1) This gene encodes a large protein that resides in the limiting membrane of endosomes and lysosomes and mediates intracellular cholesterol trafficking via binding of cholesterol to its N-terminal domain. It is predicted to have a cytoplasmic C-terminus, 13 transmembrane domains, and 3 large loops in the lumen of the endosome - the last loop being at the N-terminus. This protein transports low-density lipoproteins to late endosomal/lysosomal compartments where they are hydrolized and released as free cholesterol. Defects in this gene cause Niemann-Pick type C disease, a rare autosomal recessive neurodegenerative disorder characterized by over accumulation of cholesterol and glycosphingolipids in late endosomal/lysosomal compartments.[provided by RefSeq, Aug 2009]

NPC1 Gene-Disease associations (from GenCC):

Niemann-Pick disease, type C1
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Myriad Women’s Health
Niemann-Pick disease type C, adult neurologic onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Niemann-Pick disease type C, juvenile neurologic onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Niemann-Pick disease type C, late infantile neurologic onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Niemann-Pick disease type C, severe early infantile neurologic onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Niemann-Pick disease type C, severe perinatal form
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

NPC1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000271.5

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 171 curated pathogenic missense variants (we use a threshold of 10). The gene has 18 curated benign missense variants. Gene score misZ: 1.0917 (below the threshold of 3.09). Trascript score misZ: 1.706 (below the threshold of 3.09). GenCC associations: The gene is linked to Niemann-Pick disease, type C1, Niemann-Pick disease type C, severe early infantile neurologic onset, Niemann-Pick disease type C, late infantile neurologic onset, Niemann-Pick disease type C, adult neurologic onset, Niemann-Pick disease type C, juvenile neurologic onset, Niemann-Pick disease type C, severe perinatal form.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.984

PP5

Variant 18-23535665-A-G is Pathogenic according to our data. Variant chr18-23535665-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 547997.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5 link	c.3281T>C	p.Ile1094Thr	missense_variant	Exon 22 of 25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NPC1	ENST00000269228.10 link	c.3281T>C	p.Ile1094Thr	missense_variant	Exon 22 of 25	1	NM_000271.5	ENSP00000269228.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251410

AF XY:

0.00000736

show subpopulations

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461832

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727214

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111964

Other (OTH)

AF:

0.00

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Niemann-Pick disease, type C1

Pathogenic:2Uncertain:2

Dec 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 1094 of the NPC1 protein (p.Ile1094Thr). This variant is present in population databases (no rsID available, gnomAD 0.003%). This missense change has been observed in individuals with Niemann-Pick disease type C (PMID: 12408188, 23433426, 27139891). ClinVar contains an entry for this variant (Variation ID: 547997). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt NPC1 protein function with a positive predictive value of 95%. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.

Nov 11, 2021

Myriad Genetics, Inc.

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

NM_000271.4(NPC1):c.3281T>C(I1094T) is a missense variant classified as a variant of uncertain significance in the context of Niemann-Pick disease type C1. I1094T has been observed in cases with relevant disease (PMID: 27139891, 23433426, 12955717, 12408188). Functional assessments of this variant are not available in the literature. I1094T has been observed in population frequency databases (gnomAD: SAS 0.003%). In summary, there is insufficient evidence to classify NM_000271.4(NPC1):c.3281T>C(I1094T) as pathogenic or benign. Please note: this variant was assessed in the context of healthy population screening.

Aug 11, 2017

Mayo Clinic Laboratories, Mayo Clinic

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 16, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

NPC1-related disorder

Pathogenic:1

Mar 08, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

The NPC1 c.3281T>C variant is predicted to result in the amino acid substitution p.Ile1094Thr. This variant has been reported in the compound heterozygous state with another NPC1 variant in two sets of siblings affected with Niemann-Pick disease type C (Family 3 in Kaminski et al 2002. PubMed ID: 12408188; Pts 020 and 021 in Stampfer et al. 2013. PubMed ID: 23433426). This variant is reported in 0.0033% of alleles in individuals of South Asian descent in gnomAD. This variant is interpreted as likely pathogenic.

not specified

Uncertain:1

Jul 03, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: NPC1 c.3281T>C (p.Ile1094Thr) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 4e-06 in 251410 control chromosomes. c.3281T>C has been reported in the literature in compound heterozygous individuals affected with Niemann-Pick Disease Type C (Kaminski_2002, Mazzacuva_2016, Stampfer_2013, Rodriguez-Gil_2021, Abela_2014). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 12408188, 27139891, 23433426, 31509197, 37032242, 15465421, 22585405, 27238017, 12955717, 34296265, 31543266, 25425405). ClinVar contains an entry for this variant (Variation ID: 547997). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.79

BayesDel_addAF

Pathogenic

0.39

BayesDel_noAF

Pathogenic

0.42

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.83

Eigen

Pathogenic

0.81

Eigen_PC

Pathogenic

0.80

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

M_CAP

Uncertain

0.27

MetaRNN

Pathogenic

0.98

MetaSVM

Pathogenic

0.85

MutationAssessor

Pathogenic

3.7

PhyloP100

9.3

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-3.5

REVEL

Pathogenic

0.90

Sift

Uncertain

0.016

Sift4G

Uncertain

0.030

Vest4

0.97

ClinPred

0.97

GERP RS

5.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.68

gMVP

0.95

Mutation Taster

=4/96

disease causing (ClinVar)

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over