Niemann-Pick Type C disease (NPC) is a genetic metabolic disorder in which harmful quantities of cholesterol and other fatty substances accumulate in the cells of the body such as the spleen, liver, lungs, bone marrow and, most dramatically, the brain. Detrimental changes in either of two genes, NPC1 or NPC2, can lead to NPC disease.
Neurologically, NPC is characterized by an inability to metabolize cholesterol in the nerve cells of the brain where it accumulates and causes the premature death of these cells. This brain involvement can be extensive, leading to intellectual disability/dementia, seizures, the inability to look up and down, difficulty in walking, swallowing and talking, as well as progressive loss of hearing. The disorder may appear early in life or its onset may be delayed.
Currently, the life expectancies of patients with NPC are quite variable. Children often die at a very early age or in their early teens while some adult patients appear to be less drastically affected.
Niemann-Pick Type C is a genetically inherited disease. When two NPC carriers have children, each child has a 25% chance of developing NPC.
NPC is always fatal. The earlier the onset of the disease, the shorter the life expectancy.
People with Niemann-Pick Type C may exhibit an inability to focus, forgetfulness, learning difficulties in school, slurred speech and loss of speech, as well as depression and even hallucinations.
NPC can cause a range of signs and symptoms: enlarged liver or spleen, abnormal eye movements, trouble swallowing and speaking, difficulty walking, loss of muscle tone, the inability to control voluntary movements, poor balance, loss of coordination, and seizures.