rs1555637157

Variant names:

• chr18-23556407-C-G
• rs1555637157
• NM_000271.5:c.1162G>C

Your query was ambiguous. Multiple possible variants found:

• chr18-23556407-C-G
• chr18-23556407-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000271.5(NPC1):​c.1162G>C​(p.Ala388Pro) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: NPC1 NM_000271.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.17

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 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, 0.987

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5	c.1162G>C	p.Ala388Pro	missense_variant	Exon 8 of 25	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NPC1	ENST00000269228.10	c.1162G>C	p.Ala388Pro	missense_variant	Exon 8 of 25	1	NM_000271.5	ENSP00000269228.4
NPC1	ENST00000591051.1	c.442G>C	p.Ala148Pro	missense_variant	Exon 3 of 18	2		ENSP00000467636.1
NPC1	ENST00000540608.5	n.1076G>C		non_coding_transcript_exon_variant	Exon 6 of 16	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Nov 15, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: NPC1 c.1162G>C (p.Ala388Pro) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251218 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1162G>C has been reported in the literature in an unknown state in at least 1 individual affected with Niemann-Pick Disease (example, Park_2003). These report(s) do not provide unequivocal conclusions about association of the variant with Niemann-Pick Disease Type C. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 12955717). ClinVar contains an entry for this variant (Variation ID: 553090). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Niemann-Pick disease, type C1 Uncertain:1

Aug 02, 2017

Counsyl

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	0.65
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Uncertain	0.63	D
MutationAssessor	Pathogenic	3.3	M
PrimateAI	Uncertain	0.50	T
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.89
Sift	Uncertain	0.021	D
Sift4G	Uncertain	0.011	D
Polyphen		0.93	P
Vest4		0.94
MutPred		0.89		Gain of methylation at K392 (P = 0.055);
MVP		0.91
MPC		0.93
ClinPred		0.99	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.90
gMVP		0.97

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

Other links and lift over

dbSNP: rs1555637157; hg19: chr18-21136371;