18-23541422-C-T

Position:

chr18-23541422-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_000271.5(NPC1):c.2257G>A(p.Val753Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00021 in 1,614,112 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00016 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00021 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.727

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:

NPC1 (HGNC:):

NPC1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM1

In a domain SSD (size 165) in uniprot entity NPC1_HUMAN there are 26 pathogenic changes around while only 4 benign (87%) in NM_000271.5

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.14287668).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NPC1	NM_000271.5 linkuse as main transcript	c.2257G>A	p.Val753Met	missense_variant	15/25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	UniProt
NPC1	ENST00000269228.10 linkuse as main transcript	c.2257G>A	p.Val753Met	missense_variant	15/25	1	NM_000271.5	ENSP00000269228.4	O15118-1
NPC1	ENST00000591051.1 linkuse as main transcript	c.1333G>A	p.Val445Met	missense_variant	8/18	2		ENSP00000467636.1	K7EQ23
NPC1	ENST00000540608.5 linkuse as main transcript	n.2171G>A		non_coding_transcript_exon_variant	13/16	2
NPC1	ENST00000586718.1 linkuse as main transcript	n.-50G>A		upstream_gene_variant		3

Frequencies

GnomAD3 genomes

AF:

0.000164

AC:

AN:

152222

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

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:

0.000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000191

AC:

AN:

251422

Hom.:

AF XY:

0.000199

AC XY:

AN XY:

135888

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.000378

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.000215

AC:

314

AN:

1461890

Hom.:

Cov.:

AF XY:

0.000227

AC XY:

165

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000812

Gnomad4 FIN exome

AF:

0.0000749

Gnomad4 NFE exome

AF:

0.000259

Gnomad4 OTH exome

AF:

0.000149

GnomAD4 genome

AF:

0.000164

AC:

AN:

152222

Hom.:

Cov.:

AF XY:

0.000215

AC XY:

AN XY:

74358

show subpopulations

Gnomad4 AFR

AF:

0.000121

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:

0.000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000417

Hom.:

Bravo

AF:

0.000132

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000519

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000148

AC:

EpiCase

AF:

0.000491

EpiControl

AF:

0.000533

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Nov 29, 2017	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Mar 19, 2024	- -

Niemann-Pick disease, type C1

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 17, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Oct 31, 2018	- -

NPC1-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 20, 2024

The NPC1 c.2257G>A variant is predicted to result in the amino acid substitution p.Val753Met. This variant has not been reported in an individual with ataxia and assessed as a variant of unknown significance (Vural et al. 2021. PubMed ID: 33624863). This variant is reported in 0.039% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.087

BayesDel_addAF

Benign

-0.35

BayesDel_noAF

Benign

-0.40

CADD

Benign

0.029

DANN

Benign

0.89

DEOGEN2

Uncertain

0.59

Eigen

Benign

-1.5

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.057

LIST_S2

Benign

0.66

M_CAP

Benign

0.046

MetaRNN

Benign

0.14

MetaSVM

Benign

-0.34

MutationAssessor

Benign

1.3

PrimateAI

Benign

0.27

PROVEAN

Benign

-0.13

REVEL

Uncertain

0.37

Sift

Benign

0.065

Sift4G

Benign

0.10

Polyphen

0.64

Vest4

0.22

MVP

0.41

MPC

0.27

ClinPred

0.028

GERP RS

-12

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.037

gMVP

0.13

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

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