chr18-23551720-C-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 3P and 9B. PM1PP2BP4_StrongBP6BS1

The NM_000271.5(NPC1):c.1561G>T(p.Ala521Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000116 in 1,613,812 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A521T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000073 ( 0 hom. )

Consequence

NPC1
NM_000271.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:3

Conservation

PhyloP100: 0.449

Publications

4 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: Likely_benign. The variant received -6 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_000271.5

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.03271857).

BP6

Variant 18-23551720-C-A is Benign according to our data. Variant chr18-23551720-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 500953.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000532 (81/152322) while in subpopulation AFR AF = 0.00185 (77/41574). AF 95% confidence interval is 0.00152. There are 0 homozygotes in GnomAd4. There are 44 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

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.1561G>T	p.Ala521Ser	missense	Exon 10 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.1561G>T	p.Ala521Ser	missense	Exon 10 of 25	ENSP00000269228.4	O15118-1
NPC1	ENST00000897526.1		c.1612G>T	p.Ala538Ser	missense	Exon 10 of 25	ENSP00000567585.1
NPC1	ENST00000926494.1		c.1561G>T	p.Ala521Ser	missense	Exon 10 of 25	ENSP00000596553.1

Frequencies

GnomAD3 genomes

AF:

0.000539

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00188

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.000955

GnomAD2 exomes

AF:

0.000171

AC:

AN:

250964

AF XY:

0.000155

show subpopulations

Gnomad AFR exome

AF:

0.00247

Gnomad AMR exome

AF:

0.0000578

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:

0.000163

GnomAD4 exome

AF:

0.0000725

AC:

106

AN:

1461490

Hom.:

Cov.:

AF XY:

0.0000646

AC XY:

AN XY:

727088

show subpopulations

African (AFR)

AF:

0.00239

AC:

AN:

33470

American (AMR)

AF:

0.000112

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53372

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00000630

AC:

AN:

1111706

Other (OTH)

AF:

0.000232

AC:

AN:

60380

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.458

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:

0.000532

AC:

AN:

152322

Hom.:

Cov.:

AF XY:

0.000591

AC XY:

AN XY:

74492

show subpopulations

African (AFR)

AF:

0.00185

AC:

AN:

41574

American (AMR)

AF:

0.000131

AC:

AN:

15308

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.000945

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000220

Hom.:

Bravo

AF:

0.000672

ESP6500AA

AF:

0.00204

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000206

AC:

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Niemann-Pick disease, type C1 (4)

not provided (3)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.15

CADD

Benign

(source)

DANN

Benign

0.97

DEOGEN2

Benign

0.30

Eigen

Benign

-0.55

Eigen_PC

Benign

-0.49

FATHMM_MKL

Uncertain

0.85

LIST_S2

Benign

0.84

M_CAP

Uncertain

0.10

MetaRNN

Benign

0.033

MetaSVM

Benign

-0.45

MutationAssessor

Uncertain

2.5

PhyloP100

0.45

PrimateAI

Benign

0.39

PROVEAN

Benign

-1.1

REVEL

Uncertain

0.36

Sift

Benign

0.26

Sift4G

Benign

0.58

Polyphen

0.0030

Vest4

0.72

MVP

0.68

MPC

0.24

ClinPred

0.024

GERP RS

1.7

Varity_R

0.25

gMVP

0.76

Mutation Taster

=25/75

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

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over