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Test Code NPCseq UM Niemann-Pick Type C Disease, Full Gene Analysis

Important Note

This gene analysis is only for Niemann-Pick type C.  Please contact the Laboratory Genetic Counselors if Niemann-Pick type A or B gene analysis is desired  (  or 206-987-5400.)

Reporting Name

NPC1/NPC2 Genes, Full Gene Analysis

Useful For

Second-tier test for confirming a biochemical diagnosis of Niemann-Pick type C (NPC)


Carrier testing of individuals with a family history of NPC when an affected individual is not available for testing or disease-causing mutations have not been identified

Specimen Required

Specimen preferred to arrive within 96 hours of collection.


Submit only 1 of the following specimens:


Specimen Type: Whole blood


Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient (preferred)/Refrigerated


Specimen Type: Cultured fibroblasts

Container/Tube: T-75 or T-25 flask

Specimen Volume: 1 Full T-75 or 2 full T-25 flasks

Specimen Stability Information: Ambient (preferred)/Refrigerated <24 hours


Specimen Type: Skin biopsy

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin. Tubes can be supplied upon request (Eagle's minimum essential medium with 1% penicillin and streptomycin [T115]).

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient

Specimen Type


Specimen Minimum Volume

Blood: 1 mL

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies

Day(s) and Time(s) Performed

Performed weekly, varies

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Polymerase Chain Reaction (PCR) Amplification Followed by DNA Sequencing/Gene Dosage Analysis by Multiplex Ligation-Dependent Probe Amplification (MLPA)

Method Description

Bidirectional sequence analysis is performed to test for the presence of a mutation in all coding regions and intron/exon boundaries of the NPC1 gene and NPC2 gene. Gene dosage analysis by multiplex ligation-dependent probe amplification (MLPA) is used to test for the presence of large deletions and duplications within these genes.(Unpublished Mayo method)

Reference Values

An interpretive report will be provided.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81404-NPC2 (Niemann-Pick disease, type C2 [epididymal secretory protein E1]) (eg, Niemann-Pick disease type C2), full gene sequence    

81406-NPC1 (Niemann-Pick disease, type C1) (eg, Niemann-Pick disease), full gene sequence


Fibroblast Culture for Genetic Test

88233-Tissue culture, skin or solid tissue biopsy (if appropriate)

88240-Cryopreservation (if appropriate)

Seattle Children's Hospital Note:

In addition to sequencing CPTs above, this test also involves 81479x2  for NPC1 and NPC2 deletion/duplication


(updated 9/15/2016 by dstern) 

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NPCZ NPC1/NPC2 Genes, Full Gene Analysis In Process


Result ID Test Result Name Result LOINC Value
53533 Result Summary 50397-9
53534 Result In Process
53535 Interpretation In Process
53536 Additional Information 48767-8
53537 Specimen In Process
53538 Source 31208-2
53539 Released By No LOINC Needed

Reject Due To

Note: No specimen should be rejected. If specimen not received at appropriate temperature or in wrong anticoagulant, include note to laboratory. If questions, contact laboratory.

Testing Algorithm

If skin biopsy is received, fibroblast culture for genetic test will be added and charged separately.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULFB Fibroblast Culture for Genetic Test Yes No