chr18-23554875-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1PM2PP3_StrongPP5

The NM_000271.5(NPC1):c.1436G>A(p.Cys479Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,170 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: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 7.64

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 Likely_pathogenic. Variant got 9 ACMG points.

PM1

In a topological_domain Lumenal (size 248) in uniprot entity NPC1_HUMAN there are 30 pathogenic changes around while only 10 benign (75%) 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 18-23554875-C-T is Pathogenic according to our data. Variant chr18-23554875-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 539310.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Pathogenic=1, Uncertain_significance=2}. Variant chr18-23554875-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5 link	c.1436G>A	p.Cys479Tyr	missense_variant	Exon 9 of 25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
NPC1	ENST00000269228.10 link	c.1436G>A	p.Cys479Tyr	missense_variant	Exon 9 of 25	1	NM_000271.5	ENSP00000269228.4	O15118-1
NPC1	ENST00000591051.1 link	c.716G>A	p.Cys239Tyr	missense_variant	Exon 4 of 18	2		ENSP00000467636.1	K7EQ23
NPC1	ENST00000540608.5 link	n.1350G>A		non_coding_transcript_exon_variant	Exon 7 of 16	2
NPC1	ENST00000590301.1 link	n.111G>A		non_coding_transcript_exon_variant	Exon 1 of 2	2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152170

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

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1461776

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727194

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152170

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74336

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:

0.00000378

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 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 479 of the NPC1 protein (p.Cys479Tyr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Niemann-Pick disease (PMID: 16098014, 20718790; internal data). 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: 539310). 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%. For these reasons, this variant has been classified as Pathogenic. -

Baylor Genetics

Significance: Likely 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

- -

Nov 15, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The NPC1 c.1436G>A (p.Cys479Tyr) missense variant has been reported in two studies and is found in two individuals with Niemann-Pick disease type C, including one each in a compound heterozygous state with a second missense variant and in a heterozygous state (Fernandez-Valero et al. 2005; Macias-Vidal et al. 2011). The p.Cys479Tyr variant was absent from 100 controls and is not found in the 1000 Genomes Project, the Exome Sequencing Project, the Exome Aggregation Consortium or the Genome Aggregation Database. Based on the limited evidence, the p.Cys479Tyr variant is classified as a variant of unknown significance but suspicious for pathogenicity for Niemann-Pick disease type C. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Inborn genetic diseases

Pathogenic:1

Mar 30, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1436G>A (p.C479Y) alteration is located in coding exon 9 of the NPC1 gene. This alteration results from a G to A substitution at nucleotide position 1436, causing the cysteine (C) at amino acid position 479 to be replaced by a tyrosine (Y). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been detected in a Spanish child who developed generalized seizures at age 9 and was later diagnosed with Niemann-Pick disease type C at age 11. The child was heterozygous for this variant and a second mutation was not able to be detected (Fernandez-Valero 2005; Macías-Vidal 2011). This variant was also reported in trans with a second NPC1 mutation (p.A1054T c.3160G>A) in another Spanish child with severe infantile onset (Macías-Vidal 2011). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -

not provided

Uncertain:1

Aug 10, 2017

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.92

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.85

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

M_CAP

Pathogenic

0.71

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.2

PrimateAI

Uncertain

0.79

PROVEAN

Pathogenic

-11

REVEL

Pathogenic

0.94

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.99

MutPred

0.90

Gain of sheet (P = 0.039);

MVP

0.99

MPC

1.2

ClinPred

1.0

GERP RS

4.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.96

gMVP

0.99

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

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