18-23544946-C-T

Variant names:

• chr18-23544946-C-T
• rs3745024
• NM_000271.5:c.1947+14G>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The NM_000271.5(NPC1):​c.1947+14G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000586 in 1,193,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 27)
  • Exomes 𝑓: 0.0000059 (0 hom.)
• Consequence: NPC1 NM_000271.5 intron
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.765
• Publications: 6 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, 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

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BP6: Variant 18-23544946-C-T is Benign according to our data. Variant chr18-23544946-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 2428016.Status of the report is criteria_provided_single_submitter, 1 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.1947+14G>A		intron	N/A	NP_000262.2	O15118-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NPC1	ENST00000269228.10	TSL:1 MANE Select	c.1947+14G>A		intron	N/A	ENSP00000269228.4	O15118-1
	NPC1	ENST00000897526.1		c.1998+14G>A		intron	N/A	ENSP00000567585.1
	NPC1	ENST00000926494.1		c.1947+14G>A		intron	N/A	ENSP00000596553.1

Frequencies

GnomAD3 genomes Cov.: 27

GnomAD4 exome AF: 0.00000586 AC: 7 AN: 1193798 Hom.: 0 Cov.: 24 AF XY: 0.00000332 AC XY: 2 AN XY: 602952

African (AFR) AF: 0.00 AC: 0 AN: 30282

American (AMR) AF: 0.00 AC: 0 AN: 41612

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24582

East Asian (EAS) AF: 0.00 AC: 0 AN: 32172

South Asian (SAS) AF: 0.00 AC: 0 AN: 79238

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 47572

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5262

European-Non Finnish (NFE) AF: 0.00000793 AC: 7 AN: 882394

Other (OTH) AF: 0.00 AC: 0 AN: 50684

GnomAD4 genome Cov.: 27

Alfa AF: 0.00 Hom.: 51

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Niemann-Pick disease, type C1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	1.4
DANN	Benign	0.47
PhyloP100		-0.77

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: rs3745024; hg19: chr18-21124910;