Background: Niemann-Pick type C (NPC) disease is a rare, progressive neurodegenerative disease that affects mainly the brain, liver, and spleen but also other parts of the body. There is no cure for NPC, and symptoms only get worse over time. Symptoms can include seizures, difficulty moving or talking, or dementia. But symptoms can vary among different people with the disease. Some may have seizures, while others do not, for example. Some people begin showing symptoms in childhood; in others, symptoms may not appear until they are adults. Researchers want to learn more about why NPC affects people differently. This natural history study will gather data from people with NPC in order to understand more about the disease and how it affects the body.

Objective: This study will create the first and largest database about NPC.

Eligibility: People of any age who have NPC.

Design: Participants will have blood drawn from a vein. This will happen only once. The blood will be used to analyze the participants DNA. The participants medical records will be reviewed. The study team will collect data on participants NPC diagnosis and symptoms; they will record how long participants have had each symptom. The study team will also collect data on each participants age, sex, race, height, weight, medications, and other test results. The study team will communicate with participants. They will discuss the study and answer any questions. Participants will receive up to $190.