18-23556358-C-T

Position:

chr18-23556358-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_000271.5(NPC1):c.1211G>A(p.Arg404Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000211 in 1,613,952 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R404W) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000023 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 7.83

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 18 ACMG points.

PM1

In a topological_domain Lumenal (size 248) in uniprot entity NPC1_HUMAN there are 75 pathogenic changes around while only 19 benign (80%) in NM_000271.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr18-23556359-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 499939.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.967

PP5

Variant 18-23556358-C-T is Pathogenic according to our data. Variant chr18-23556358-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 188794.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr18-23556358-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NPC1	NM_000271.5 linkuse as main transcript	c.1211G>A	p.Arg404Gln	missense_variant	8/25	ENST00000269228.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NPC1	ENST00000269228.10 linkuse as main transcript	c.1211G>A	p.Arg404Gln	missense_variant	8/25	1	NM_000271.5	P1	O15118-1
NPC1	ENST00000591051.1 linkuse as main transcript	c.494G>A	p.Arg165Gln	missense_variant	3/18	2
NPC1	ENST00000540608.5 linkuse as main transcript	n.1125G>A		non_coding_transcript_exon_variant	6/16	2

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152090

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:

0.0000358

AC:

AN:

251292

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135804

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

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:

0.0000440

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000226

AC:

AN:

1461862

Hom.:

Cov.:

AF XY:

0.0000234

AC XY:

AN XY:

727230

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.0000225

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152090

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74290

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

Alfa

AF:

0.0000614

Hom.:

Bravo

AF:

0.0000302

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000412

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type C1

Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Mar 24, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 21, 2023	This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 404 of the NPC1 protein (p.Arg404Gln). This variant is present in population databases (rs139751448, gnomAD 0.009%). This missense change has been observed in individual(s) with Nieman-Pick disease type C (PMID: 11349231, 11545687, 26666848, 27581084; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 188794). 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 with a positive predictive value of 95%. Experimental studies have shown that this missense change affects NPC1 function (PMID: 22065762). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Counsyl	Jan 23, 2019	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Feb 08, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Oct 31, 2018	- -

Niemann-Pick disease, type C

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Dec 01, 2016

Variant summary: The c.1211G>A (p.Arg404Gln) in NPC1 gene is a missense change that alters a highly conserved nucleotide and 4/5 in silico tools predict deleterious outcome. These predictions were also confirmed by functional studies, where very low esterification values were found in fibroblasts of a patient homozygous for R404Q. The variant is present in the large control population dataset of ExAC at a frequency 0.000041 (5/121346 chrs tested), which does not exceed the estimated maximal expected allele frequency of a pathogenic variant (0.0028). The variant was identified in multiple affected individuals with established dx of classical NPC. Lastly, multiple reputable diagnostic centers classified the variant of interest as Pathogenic. Taken together, the variant was classified as Pathogenic. -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 26, 2024

Relatively common in affected patients, occurring on 3.1% of NPC1 alleles (PMID: 12955717); Published functional studies demonstrate R404Q significantly decreased binding to NPC2 compared the wild-type protein (PMID: 22065762); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 12974729, 27307437, 26666848, 11333381, 10480349, 15465421, 11545687, 30188717, 11349231, 27581084, 19744920, 26981555, 32222928, 32317543, 38178268, 12955717, 22065762) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.44

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.86

Eigen

Pathogenic

0.90

Eigen_PC

Pathogenic

0.81

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.42

MetaRNN

Pathogenic

0.97

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.2

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.51

PROVEAN

Uncertain

-4.0

REVEL

Pathogenic

0.90

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.94

MVP

0.94

MPC

0.97

ClinPred

1.0

GERP RS

4.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.8

Varity_R

0.90

gMVP

0.97

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.31

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.31

Position offset: -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