18-23539823-T-G

Position:

• chr18-23539823-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP3_Moderate PP5

The NM_000271.5(NPC1):​c.2783A>C​(p.Gln928Pro) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,856 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 Pathogenic (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: NPC1 NM_000271.5 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.18

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 7 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000271.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908
• PP5: Variant 18-23539823-T-G is Pathogenic according to our data. Variant chr18-23539823-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 2957.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NPC1	NM_000271.5	c.2783A>C	p.Gln928Pro	missense_variant	18/25	ENST00000269228.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NPC1	ENST00000269228.10	c.2783A>C	p.Gln928Pro	missense_variant	18/25	1	NM_000271.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461856 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 727234

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Niemann-Pick disease, type C1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jul 11, 1997

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.17
CADD	Benign	22
DANN	Benign	0.97
DEOGEN2	Uncertain	0.73	D
Eigen	Benign	0.0055
Eigen_PC	Benign	0.19
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.82	T
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Uncertain	0.33	D
MutationAssessor	Benign	1.9	L
MutationTaster	Benign	0.020	A;A
PrimateAI	Benign	0.30	T
PROVEAN	Uncertain	-2.8	D
REVEL	Uncertain	0.61
Sift	Benign	0.047	D
Sift4G	Benign	0.10	T
Polyphen		0.082	B
Vest4		0.40
MutPred		0.83		Loss of stability (P = 0.092);
MVP		0.86
MPC		0.35
ClinPred		0.75	D
GERP RS		5.5
Varity_R		0.74
gMVP		0.88

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: rs28940897; hg19: chr18-21119787;