How is Niemann-Pick type C disease diagnosed?

Many cases of Niemann-Pick type C disease (NP-C) are either misdiagnosed or go unnoticed altogether due to the rarity of the disease and the highly variable symptoms.¹ Furthermore, a definite diagnosis of NP-C requires complicated tests that can only be carried out at a limited number of specialist laboratories. Fortunately, new diagnostic tests are being developed that will make it easier to precisely diagnose NP-C in the future.

If NP-C is suspected (see section: What are the Symptoms of NP-C), laboratory tests are performed to confirm the diagnosis. These tests may include:¹

	A skin biopsy to look for any changes in the storage and movement of cholesterol. This involves taking a piece of skin to grow certain cells (fibroblasts) in the laboratory.
	DNA tests to look for mutations on one of the two genes (NPC1 and NPC2) that cause NP-C (see section: What causes NP-C?)
	Brain scans such as magnetic resonance imaging (MRI) or computed topography (CT). These will assess any changes in the brain in patients with advanced disease showing signs of intellectual decline.

References

1. Wraith JE, Imrie J. Understanding Niemann-Pick disease type C and its potential treatment. UK Blackwell Publishing, 2007.