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. Variant got -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

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]

ACMG classification

Verdict is Likely_benign. Variant got -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 id is 2428016.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPC1	NM_000271.5	c.1947+14G>A		intron_variant	Intron 12 of 24	ENST00000269228.10	NP_000262.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NPC1	ENST00000269228.10	c.1947+14G>A		intron_variant	Intron 12 of 24	1	NM_000271.5	ENSP00000269228.4
NPC1	ENST00000591051.1	c.1023+14G>A		intron_variant	Intron 5 of 17	2		ENSP00000467636.1
NPC1	ENST00000540608.5	n.1861+14G>A		intron_variant	Intron 10 of 15	2

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

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000793

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 27

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Niemann-Pick disease, type C1 Benign:1

Nov 01, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

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

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

Publications

LitVar

Other links and lift over

dbSNP: rs3745024; hg19: chr18-21124910;