NM_000271.5:c.2604+1G>A

Variant names:

• chr18-23540447-C-T
• rs1555633454
• NM_000271.5:c.2604+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000271.5(NPC1):​c.2604+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: NPC1 NM_000271.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.71
• Publications: 1 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: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.023455825 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-23540447-C-T is Pathogenic according to our data. Variant chr18-23540447-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 501356.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 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.2604+1G>A		splice_donor 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.2604+1G>A		splice_donor intron	N/A	ENSP00000269228.4	O15118-1
	NPC1	ENST00000897526.1		c.2655+1G>A		splice_donor intron	N/A	ENSP00000567585.1
	NPC1	ENST00000926494.1		c.2604+1G>A		splice_donor intron	N/A	ENSP00000596553.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1391038 Hom.: 0 Cov.: 27 AF XY: 0.00 AC XY: 0 AN XY: 695082

African (AFR) AF: 0.00 AC: 0 AN: 32070

American (AMR) AF: 0.00 AC: 0 AN: 44426

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25678

East Asian (EAS) AF: 0.00 AC: 0 AN: 39258

South Asian (SAS) AF: 0.00 AC: 0 AN: 83884

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51750

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5656

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1050228

Other (OTH) AF: 0.00 AC: 0 AN: 58088

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	Niemann-Pick disease, type C1 (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	31
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.97	D
PhyloP100		7.7
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.99		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1555633454; hg19: chr18-21120411;