chr18-23556268-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1PM2PP2PP5_Very_Strong

The NM_000271.5(NPC1):c.1301C>T(p.Pro434Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000297 in 1,613,970 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P434S) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000031 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3U:1

Conservation

PhyloP100: 7.62

Publications

8 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 13 ACMG points.

PM1

In a hotspot region, there are 2 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.

PP5

Variant 18-23556268-G-A is Pathogenic according to our data. Variant chr18-23556268-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 429322.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5 link	c.1301C>T	p.Pro434Leu	missense_variant	Exon 8 of 25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
NPC1	ENST00000269228.10 link	c.1301C>T	p.Pro434Leu	missense_variant	Exon 8 of 25	1	NM_000271.5	ENSP00000269228.4	O15118-1
NPC1	ENST00000591051.1 link	c.581C>T	p.Pro194Leu	missense_variant	Exon 3 of 18	2		ENSP00000467636.1	K7EQ23
NPC1	ENST00000540608.5 link	n.1215C>T		non_coding_transcript_exon_variant	Exon 6 of 16	2

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152134

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251404

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000308

AC:

AN:

1461836

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

727226

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

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:

0.0000232

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000369

AC:

AN:

1111972

Other (OTH)

AF:

0.0000166

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.476

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152134

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74318

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41416

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68042

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000266

Hom.:

Bravo

AF:

0.00000756

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type C1

Pathogenic:2Uncertain:1

Feb 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 434 of the NPC1 protein (p.Pro434Leu). This variant is present in population databases (rs774333145, gnomAD 0.007%). This missense change has been observed in individual(s) with Niemann-Pick disease type C (PMID: 16098014, 26981555, 36325261). 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: 429322). 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 not expected to disrupt NPC1 protein function with a negative predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Oct 17, 2017

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Jun 20, 2024

Institute of Human Genetics Munich, TUM University Hospital

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Aug 16, 2015

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The P434L variant has been reported previously in an individual with a biochemical diagnosis of Niemann-Pick disease type C (NPC) who also carried another missense variant in the NPC1 gene, although phase was not determined and functional studies were not performed (Fernandez-Valero et al., 2005). The P434L variant is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved in mammals. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. A missense variant in a nearby residue (P433L) has been reported in the Human Gene Mutation Database in association with NPC (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, the P434L variant is a strong candidate for a pathogenic variant, however the possibility that it is a benign variant cannot be excluded. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Pathogenic

0.18

CADD

Uncertain

(source)

DANN

Benign

0.95

DEOGEN2

Benign

0.27

Eigen

Benign

0.088

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.90

M_CAP

Benign

0.049

MetaRNN

Uncertain

0.54

MetaSVM

Uncertain

-0.26

MutationAssessor

Benign

1.5

PhyloP100

7.6

PrimateAI

Benign

0.42

PROVEAN

Benign

0.040

REVEL

Uncertain

0.51

Sift

Benign

0.18

Sift4G

Benign

0.14

Polyphen

0.0010

Vest4

0.60

MVP

0.82

MPC

0.29

ClinPred

0.49

GERP RS

5.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.23

gMVP

0.82

Mutation Taster

=25/75

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over