rs1181604094

Variant names:

• chr18-23540455-A-G
• rs1181604094
• NM_000271.5:c.2597T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Moderate

The NM_000271.5(NPC1):​c.2597T>C​(p.Met866Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000692 in 1,444,740 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M866V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: NPC1 NM_000271.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 9.09
• 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: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 6 uncertain in NM_000271.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 171 curated pathogenic missense variants (we use a threshold of 10). The gene has 18 curated benign missense variants. Gene score misZ: 1.0917 (below the threshold of 3.09). Trascript score misZ: 1.706 (below the threshold of 3.09). GenCC associations: The gene is linked to Niemann-Pick disease type C, severe early infantile neurologic onset, Niemann-Pick disease type C, late infantile neurologic onset, Niemann-Pick disease type C, juvenile neurologic onset, Niemann-Pick disease type C, severe perinatal form, Niemann-Pick disease type C, adult neurologic onset, Niemann-Pick disease, type C1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.934
• PP5: Variant 18-23540455-A-G is Pathogenic according to our data. Variant chr18-23540455-A-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 556263.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.2597T>C	p.Met866Thr	missense	Exon 17 of 25	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.2597T>C	p.Met866Thr	missense	Exon 17 of 25	ENSP00000269228.4	O15118-1
	NPC1	ENST00000897526.1		c.2648T>C	p.Met883Thr	missense	Exon 17 of 25	ENSP00000567585.1
	NPC1	ENST00000926494.1		c.2597T>C	p.Met866Thr	missense	Exon 17 of 25	ENSP00000596553.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249142 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000545

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.92e-7 AC: 1 AN: 1444740 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 719526

African (AFR) AF: 0.00 AC: 0 AN: 33154

American (AMR) AF: 0.00 AC: 0 AN: 44624

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26054

East Asian (EAS) AF: 0.00 AC: 0 AN: 39594

South Asian (SAS) AF: 0.00 AC: 0 AN: 85538

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52560

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 9.11e-7 AC: 1 AN: 1097668

Other (OTH) AF: 0.00 AC: 0 AN: 59798

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	1	-	Niemann-Pick disease, type C1 (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.83	D
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.50	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	H
PhyloP100		9.1
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.66		Loss of stability (P = 0.0361)
MVP		0.96
MPC		0.58
ClinPred		0.98	D
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.88
Mutation Taster		=2/98	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs1181604094; hg19: chr18-21120419;