18-23541355-T-G

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM2PP3_StrongPP5_Very_Strong

The NM_000271.5(NPC1):c.2324A>C(p.Gln775Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,134 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 Pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4O:1

Conservation

PhyloP100: 7.95

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 16 ACMG points.

PM1

In a transmembrane_region Helical (size 23) in uniprot entity NPC1_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000271.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.992

PP5

Variant 18-23541355-T-G is Pathogenic according to our data. Variant chr18-23541355-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 21134.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr18-23541355-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5 link	c.2324A>C	p.Gln775Pro	missense_variant	Exon 15 of 25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
NPC1	ENST00000269228.10 link	c.2324A>C	p.Gln775Pro	missense_variant	Exon 15 of 25	1	NM_000271.5	ENSP00000269228.4	O15118-1
NPC1	ENST00000591051.1 link	c.1400A>C	p.Gln467Pro	missense_variant	Exon 8 of 18	2		ENSP00000467636.1	K7EQ23
NPC1	ENST00000540608.5 link	n.2238A>C		non_coding_transcript_exon_variant	Exon 13 of 16	2
NPC1	ENST00000586718.1 link	n.18A>C		non_coding_transcript_exon_variant	Exon 1 of 3	3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152244

Hom.:

Cov.:

show subpopulations

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251470

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135904

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152244

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

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

Bravo

AF:

0.0000227

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type C1

Pathogenic:2Other:1

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Jul 09, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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) performed at Invitae indicates that this missense variant is expected to disrupt NPC1 protein function. For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects NPC1 function (PMID: 30923329). ClinVar contains an entry for this variant (Variation ID: 21134). This missense change has been observed in individual(s) with Niemann-Pick Type C (PMID: 11333381, 16098014, 20718790, 28222799). This variant is present in population databases (rs80358253, gnomAD 0.002%). This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 775 of the NPC1 protein (p.Gln775Pro). -

Niemann-Pick disease, type C

Pathogenic:1

Jul 26, 2024

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: NPC1 c.2324A>C (p.Gln775Pro) results in a non-conservative amino acid change located in the Sterol-sensing domain (IPR000731) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251470 control chromosomes. c.2324A>C has been reported in the literature in multiple homozygous and compound heterozygous individuals affected with Niemann-Pick Disease Type C (e.g. Millat_2001, Fernandez-Valero_2005). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 16098014, 11333381). ClinVar contains an entry for this variant (Variation ID: 21134). Based on the evidence outlined above, the variant was classified as pathogenic. -

NPC1-related disorder

Pathogenic:1

Apr 29, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The NPC1 c.2324A>C variant is predicted to result in the amino acid substitution p.Gln775Pro. This variant has been reported in the homozygous and compound heterozygous states in multiple individuals with Niemann-Pick disease type C (see for example, Table 3, Millat et al. 2001. PubMed ID: 11333381; Table 4, Fernandez-Valero et al. 2005. PubMed ID: 16098014; Table 2, Shammas et al. 2019. PubMed ID: 30923329). This variant is reported in 0.0018% of alleles in individuals of European (non-Finnish) descent in gnomAD. This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Pathogenic

0.55

BayesDel_noAF

Pathogenic

0.57

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.98

Eigen

Pathogenic

0.99

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.94

M_CAP

Pathogenic

0.70

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.6

PrimateAI

Uncertain

0.62

PROVEAN

Pathogenic

-5.4

REVEL

Pathogenic

0.99

Sift

Uncertain

0.0030

Sift4G

Uncertain

0.0040

Polyphen

1.0

Vest4

1.0

MutPred

0.90

Gain of catalytic residue at L774 (P = 0.1853);

MVP

0.98

MPC

1.0

ClinPred

0.99

GERP RS

5.9

Varity_R

0.99

gMVP

0.99

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over