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Niemann-Pick Disease Type C via the NPC1 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
4811 NPC1 81406 81406,81479 $990 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
4811NPC181406 81406,81479 $990 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Testing run on PG-Select capture probes does not include exome-wide CNV analysis. Reflex is available to PGxome or an exome-based panel, or you can use this gene list to create a custom panel (click here).

Click here for costs to reflex to whole PGxome.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • Jana Paderova, PhD

Clinical Features and Genetics

Clinical Features

Niemann-Pick disease type C (NPC) is a lipid storage disorder in which defects in the intracellular transport and trafficking of low-density lipoprotein (LDL)-derived cholesterol result in the accumulation of cholesterol and other lipids in tissues. NPC is characterized by an extensive clinical heterogeneity with regards to the age of onset, initial symptoms, severity, and progression. NPC can present at any time from intrauterine to the sixth decade with liver failure, incidental organomegaly, or a wide variety of neurological and psychiatric symptoms. Most common clinical features include enlarged spleen and liver, jaundice, dystonia, seizures, tremor, ataxia, vertical supranuclear gaze palsy, learning difficulty, and slurred speech (Patterson, Neurologist 9:301-310, 2003; Vanier and Millat Clin Genet 64:269-281, 2003). Cases with fetal onset, detected ultrasonically in the form of severe ascites, were reported (Maconochie et al. Arch Dis Child 64:1391-1393, 1989; Manning et al. Arch Dis Child 65:335-336, 1990; Spiegel et al. Am J Med Genet 149A:446-450, 2009). NPC occurs worldwide; however, it is more common in two genetic isolates. The first isolate is a French population from Normandy, who settled in Nova Scotia (Millat et al. Am J Hum Genet 65:1321-1329, 1999); the second is a Hispanic population from the Upper Rio Grande Valley in the United States, who settled in New Mexico and Colorado (Wenger et al. Am J Dis Child 131:955-961, 1977).


NPC is inherited with an autosomal recessive manner and is further divided into two subtypes, NPC1 and NPC2, based on the causative gene. Clinically, NPC1 and NPC2 are identical. NPC1 (OMIM 257220) is caused by variants in the NPC1 gene (Carstea et al. Science 277:228-231, 1997). Over 270 variants, distributed throughout the gene, have been reported and include missense/nonsense (~70%), small insertion/deletions (~22%), and splicing (< 1%). Gross insertions and deletions are apparently rare. Two founder variants have been identified. The G3097T substitution was found in all patients from the Nova Scotia isolate (Greer et al. Am J Hum Genet 63:52-54, 1998). The T3182C substitution, which apparently originated in Western Europe, was detected in all Hispanic patients from the Upper Rio Grande isolate (Millat et al. Am J Hum Genet 65:1321-1329, 1999). The NPC1 gene encodes a lysosomal-endosomal transmembrane protein required for the egress of lipids from the lysosome.

Clinical Sensitivity - Sequencing with CNV PG-Select

This test detects variants in ~ 90 % of individuals with NPC (Park et al. Hum Mutat 22:313-325, 2003).

Testing Strategy

This test provides full coverage of all coding exons of the NPC1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

All patients with clinical features suggestive of NPC and asymptomatic carrier relatives. Candidates for this test may also include: (1) Patients with unexplained dementia or psychiatric illness and cognitive impairment, particularly when accompanied by ataxia, dystonia, or vertical supranuclear gaze palsy; (2) infants with unexplained cholestatic jaundice; and (3) older children with progressive liver disease (See Patterson Neurologist 9:301-310, 2003). This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in NPC1.


Official Gene Symbol OMIM ID
NPC1 607623
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Niemann-Pick Disease Type C1 AR 257220

Related Test

Niemann-Pick Disease Type C Panel


  • Carstea, E. D., et.al. (1997). "Niemann-Pick C1 disease gene: homology to mediators of cholesterol homeostasis." Science 277(5323): 228-31. PubMed ID: 9211849
  • Greer, W. L., et.al. (1998). "The Nova Scotia (type D) form of Niemann-Pick disease is caused by a G3097-->T transversion in NPC1." Am J Hum Genet 63(1): 52-4. PubMed ID: 9634529
  • Maconochie, I. K., et.al. (1989). "Fetal ascites: an unusual presentation of Niemann-Pick disease type C." Arch Dis Child 64(10 Spec No): 1391-3. PubMed ID: 2589877
  • Manning, D. J., et.al. (1990). "Fetal ascites: an unusual presentation of Niemann-Pick disease type C." Arch Dis Child 65(3): 335-6. PubMed ID: 2334227
  • Millat, G., et.al. (1999). "Niemann-Pick C1 disease: the I1061T substitution is a frequent mutant allele in patients of Western European descent and correlates with a classic juvenile phenotype." Am J Hum Genet 65(5): 1321-9. PubMed ID: 10521297
  • Park, W. D., et.al. (2003). "Identification of 58 novel mutations in Niemann-Pick disease type C: correlation with biochemical phenotype and importance of PTC1-like domains in NPC1." Hum Mutat 22(4): 313-25. PubMed ID: 12955717
  • Patterson, M. C. (2003). "A riddle wrapped in a mystery: understanding Niemann-Pick disease, type C." Neurologist 9(6): 301-10. PubMed ID: 14629784
  • Spiegel, R., et.al. (2009). "The clinical spectrum of fetal Niemann-Pick type C." Am J Med Genet A 149A(3): 446-50. PubMed ID: 19206179
  • Vanier, M. T., Millat, G. (2003). "Niemann-Pick disease type C." Clin Genet 64(4): 269-81. PubMed ID: 12974729
  • Wenger, D. A., et.al. (1977). "Nine cases of sphingomyelin lipidosis, a new variant in Spanish-American Children. Juvenile variant of Niemann-Pick Disease with foamy and sea-blue histiocytes." Am J Dis Child 131(9): 955-61. PubMed ID: 900082


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

Specimen Types

Specimen Requirements and Shipping Details

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STAT and Prenatal Test Options are not available with Patient Plus.

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Note: acceptable specimen types are whole blood and DNA from whole blood only.
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