chr18-23537607-C-A

Variant names:

• chr18-23537607-C-A
• rs4800488
• NM_000271.5:c.3042-731G>T

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_000271.5(NPC1):​c.3042-731G>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.47 in 151,970 control chromosomes in the GnomAD database, including 17,097 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: 𝑓 0.47 (17097 hom., cov: 31)
• Consequence: NPC1 NM_000271.5 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.00600
• Publications: 11 publications found

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

ACMG classification

Our verdict: Benign. The variant received -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.9).
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.607 is higher than 0.05.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NPC1	NM_000271.5	MANE Select	c.3042-731G>T		intron	N/A	NP_000262.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NPC1	ENST00000269228.10	TSL:1 MANE Select	c.3042-731G>T		intron	N/A	ENSP00000269228.4
	NPC1	ENST00000591051.1	TSL:2	c.2118-731G>T		intron	N/A	ENSP00000467636.1
	NPC1	ENST00000591075.1	TSL:4	n.675-731G>T		intron	N/A

Frequencies

GnomAD3 genomes AF: 0.469 AC: 71278 AN: 151850 Hom.: 17081 Cov.: 31

Gnomad AFR AF: 0.399

Gnomad AMI AF: 0.423

Gnomad AMR AF: 0.574

Gnomad ASJ AF: 0.308

Gnomad EAS AF: 0.625

Gnomad SAS AF: 0.494

Gnomad FIN AF: 0.518

Gnomad MID AF: 0.323

Gnomad NFE AF: 0.478

Gnomad OTH AF: 0.442

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome AF: 0.470 AC: 71352 AN: 151970 Hom.: 17097 Cov.: 31 AF XY: 0.474 AC XY: 35178 AN XY: 74242

African (AFR) AF: 0.399 AC: 16543 AN: 41426

American (AMR) AF: 0.574 AC: 8765 AN: 15272

Ashkenazi Jewish (ASJ) AF: 0.308 AC: 1068 AN: 3470

East Asian (EAS) AF: 0.625 AC: 3229 AN: 5164

South Asian (SAS) AF: 0.495 AC: 2381 AN: 4812

European-Finnish (FIN) AF: 0.518 AC: 5470 AN: 10550

Middle Eastern (MID) AF: 0.323 AC: 95 AN: 294

European-Non Finnish (NFE) AF: 0.478 AC: 32475 AN: 67962

Other (OTH) AF: 0.446 AC: 941 AN: 2110

Alfa AF: 0.473 Hom.: 9716

Bravo AF: 0.474

Asia WGS AF: 0.553 AC: 1921 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.90
CADD	Benign	2.2
DANN	Benign	0.56
PhyloP100		0.0060
Mutation Taster		=100/0	polymorphism (auto)

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

Other links and lift over

dbSNP: rs4800488; hg19: chr18-21117571;