Genetic Variant NM_000271.5:c.1901A>G (chr18-23545006-T-C) – ACMG Classification: Pathogenic (19 pts)

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong

The NM_000271.5(NPC1):c.1901A>G(p.Tyr634Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000324 in 1,542,326 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y634F) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000014 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 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: 8.00

Publications

5 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, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Laboratory for Molecular Medicine, G2P
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 19 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 3 uncertain 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 chr18-23545006-T-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1019102.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

PP5

Variant 18-23545006-T-C is Pathogenic according to our data. Variant chr18-23545006-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 553800.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000271.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NPC1	NM_000271.5	MANE Select	c.1901A>G	p.Tyr634Cys	missense	Exon 12 of 25	NP_000262.2	O15118-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
NPC1	ENST00000269228.10	TSL:1 MANE Select	c.1901A>G	p.Tyr634Cys	missense	Exon 12 of 25	ENSP00000269228.4	O15118-1
NPC1	ENST00000897526.1		c.1952A>G	p.Tyr651Cys	missense	Exon 12 of 25	ENSP00000567585.1
NPC1	ENST00000926494.1		c.1901A>G	p.Tyr634Cys	missense	Exon 12 of 25	ENSP00000596553.1

Frequencies

GnomAD3 genomes

AF:

0.0000144

AC:

AN:

138932

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000525

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251366

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000214

AC:

AN:

1403394

Hom.:

Cov.:

AF XY:

0.00000287

AC XY:

AN XY:

697382

show subpopulations

African (AFR)

AF:

0.0000613

AC:

AN:

32608

American (AMR)

AF:

0.0000234

AC:

AN:

42750

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24988

East Asian (EAS)

AF:

0.00

AC:

AN:

33774

South Asian (SAS)

AF:

0.00

AC:

AN:

85652

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48134

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5614

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1072988

Other (OTH)

AF:

0.00

AC:

AN:

56886

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

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:

0.0000144

AC:

AN:

138932

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

66158

show subpopulations

African (AFR)

AF:

0.0000525

AC:

AN:

38088

American (AMR)

AF:

0.00

AC:

AN:

12036

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3430

East Asian (EAS)

AF:

0.00

AC:

AN:

4316

South Asian (SAS)

AF:

0.00

AC:

AN:

4274

European-Finnish (FIN)

AF:

0.00

AC:

AN:

7666

Middle Eastern (MID)

AF:

0.00

AC:

AN:

284

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

66010

Other (OTH)

AF:

0.00

AC:

AN:

1930

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Niemann-Pick disease, type C1 (3)

Niemann-Pick disease, type C (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.72

BayesDel_addAF

Pathogenic

0.39

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.87

Eigen

Pathogenic

0.92

Eigen_PC

Pathogenic

0.85

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.50

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.8

PhyloP100

8.0

PrimateAI

Uncertain

0.64

PROVEAN

Pathogenic

-9.0

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.97

MutPred

0.91

Gain of catalytic residue at Y634 (P = 0.1836)

MVP

0.99

MPC

1.0

ClinPred

1.0

GERP RS

6.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.82

gMVP

0.96

Mutation Taster

=9/91

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over