14-74486378-G-T

Position:

• chr14-74486378-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_006432.5(NPC2):​c.141C>A​(p.Cys47Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,453,792 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 (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: NPC2 NM_006432.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 1.29

Genes affected

NPC2 (HGNC:14537): (NPC intracellular cholesterol transporter 2) This gene encodes a protein containing a lipid recognition domain. The encoded protein may function in regulating the transport of cholesterol through the late endosomal/lysosomal system. Mutations in this gene have been associated with Niemann-Pick disease, type C2 and frontal lobe atrophy. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 14-74486378-G-T is Pathogenic according to our data. Variant chr14-74486378-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 21456.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NPC2	NM_006432.5	c.141C>A	p.Cys47Ter	stop_gained	2/5	ENST00000555619.6	NP_006423.1
NPC2	NM_001363688.1	c.141C>A	p.Cys47Ter	stop_gained	2/4		NP_001350617.1
NPC2	NM_001375440.1	c.141C>A	p.Cys47Ter	stop_gained	2/4		NP_001362369.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NPC2	ENST00000555619.6	c.141C>A	p.Cys47Ter	stop_gained	2/5	1	NM_006432.5	ENSP00000451112	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000843 AC: 2 AN: 237216 Hom.: 0 AF XY: 0.00000784 AC XY: 1 AN XY: 127520

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000353

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000933

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1453792 Hom.: 0 Cov.: 31 AF XY: 0.00000415 AC XY: 3 AN XY: 722096

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000356

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Niemann-Pick disease, type C2 Pathogenic:2 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 26, 2023	This sequence change creates a premature translational stop signal (p.Cys47*) in the NPC2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in NPC2 are known to be pathogenic (PMID: 25145893). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with Niemann-Pick Type C (PMID: 15937921, 28095804). ClinVar contains an entry for this variant (Variation ID: 21456). For these reasons, this variant has been classified as Pathogenic. -
not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, no assertion criteria provided	research	Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics	Jun 25, 2014	- -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 18, 2022

The c.141C>A (p.C47*) alteration, located in exon 2 (coding exon 2) of the NPC2 gene, consists of a C to A substitution at nucleotide position 141. This changes the amino acid from a cysteine (C) to a stop codon at amino acid position 47. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. This alteration has been reported in the homozygous state in patients with features of Niemann-Pick disease, type C2 (Chikh, 2005; Sheth, 2017). Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Uncertain	0.27
Eigen_PC	Benign	0.012
FATHMM_MKL	Uncertain	0.89	D
MutationTaster	Benign	1.0	A;A;A;A;A
Vest4		0.93
ClinPred		1.0	D
GERP RS		2.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs80358263; hg19: chr14-74953081;