chr18-23544950-C-T

Variant names:

• chr18-23544950-C-T
• rs71534236
• NM_000271.5:c.1947+10G>A

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_000271.5(NPC1):​c.1947+10G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000603 in 1,415,994 control chromosomes in the GnomAD database, including 32 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0031 (21 hom., cov: 27)
  • Exomes 𝑓: 0.00032 (11 hom.)
• Consequence: NPC1 NM_000271.5 intron
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:6
• Conservation: PhyloP100: 0.104
• Publications: 2 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, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Myriad Women’s Health
• 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: Benign. The variant received -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.85).
• BP6: Variant 18-23544950-C-T is Benign according to our data. Variant chr18-23544950-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 281050.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00308 (443/143802) while in subpopulation AFR AF = 0.0102 (413/40346). AF 95% confidence interval is 0.00942. There are 21 homozygotes in GnomAd4. There are 227 alleles in the male GnomAd4 subpopulation. Median coverage is 27. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 21 AR gene

Transcripts

RefSeq

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

Frequencies

GnomAD3 genomes AF: 0.00311 AC: 447 AN: 143688 Hom.: 21 Cov.: 27

Gnomad AFR AF: 0.0103

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00125

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000232

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000126

Gnomad OTH AF: 0.00205

GnomAD2 exomes AF: 0.000815 AC: 199 AN: 244166 AF XY: 0.000641

Gnomad AFR exome AF: 0.0112

Gnomad AMR exome AF: 0.000567

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000550

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000273

Gnomad OTH exome AF: 0.000168

GnomAD4 exome AF: 0.000323 AC: 411 AN: 1272192 Hom.: 11 Cov.: 26 AF XY: 0.000289 AC XY: 185 AN XY: 640110

African (AFR) AF: 0.0103 AC: 322 AN: 31236

American (AMR) AF: 0.000559 AC: 24 AN: 42970

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25068

East Asian (EAS) AF: 0.00 AC: 0 AN: 34646

South Asian (SAS) AF: 0.0000611 AC: 5 AN: 81850

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49066

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5458

European-Non Finnish (NFE) AF: 0.0000169 AC: 16 AN: 948408

Other (OTH) AF: 0.000823 AC: 44 AN: 53490

GnomAD4 genome AF: 0.00308 AC: 443 AN: 143802 Hom.: 21 Cov.: 27 AF XY: 0.00323 AC XY: 227 AN XY: 70360

African (AFR) AF: 0.0102 AC: 413 AN: 40346

American (AMR) AF: 0.00124 AC: 18 AN: 14458

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3364

East Asian (EAS) AF: 0.00 AC: 0 AN: 4908

South Asian (SAS) AF: 0.00 AC: 0 AN: 4310

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10008

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 290

European-Non Finnish (NFE) AF: 0.000126 AC: 8 AN: 63298

Other (OTH) AF: 0.00203 AC: 4 AN: 1972

Alfa AF: 0.000366 Hom.: 17

Bravo AF: 0.00323

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Benign:3

-

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 29, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not specified Benign:2

Jul 23, 2015

Eurofins Ntd Llc (ga)

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Niemann-Pick disease, type C1 Benign:1

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.85
CADD	Benign	0.90
DANN	Benign	0.45
PhyloP100		0.10
Mutation Taster		=100/0	polymorphism

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: rs71534236; hg19: chr18-21124914;