What is TPP1-related Neuronal Ceroid Lipofuscinosis?
TPP1-related neuronal ceroid lipofuscinosis (NCL) is an inherited disease that causes degeneration of the brain leading to a progressive loss of mental and motor skills. It can also cause blindness and typically leads to an early death. In the final stages of the disease, an affected person will be in a vegetative state.
There are several forms of NCL, largely differentiated by the gene that carries the mutation and the age at which symptoms begin. Mutations in the TPP1 gene typically result in the classic late infantile form or juvenile form of NCL.
Classic Late Infantile Form (LINCL)
The symptoms of classic LINCL typically begin between the ages of 2 and 4. Seizures are often the first sign, followed by a loss of the physical and mental milestones already achieved. Dementia soon follows along with a loss of motor coordination. Children with classic LINCL become blind between the ages of 4 and 6. They are often bedridden after the age of 6 and are unable to take care of themselves. Their life expectancy ranges from 6 to 40, with many succumbing to the disease by their 20s.
Juvenile Form (JNCL)
The symptoms of JNCL, also called Batten disease, often begin between the ages of 4 and 10. These children rapidly lose their vision, becoming completely blind within two to four years. People with JNCL often develop periodic seizures between the ages of 5 and 18.
Between the ages of 8 and 14, mental functions typically decline. Children may have difficulty with speech and show behavioral problems. Some people with JNCL also develop psychiatric problems including disturbed thoughts, attention problems, and aggression. These problems can eventually progress to dementia.
People with JNCL also show a decline in motor function and may have difficulty controlling their own movement.
How common is TPP1-related Neuronal Ceroid Lipofuscinosis?
Approximately 1 in 25,000 people globally are affected by some form of NCL. These diseases are most common in Scandinavian countries, but occur elsewhere as well. In the United States, it is estimated that 25,000 families are affected by some form of NCL.
Worldwide, 0.46 per 100,000 infants are born with TPP1-related NCL.
Mutations that cause TPP1-related NCL are more common in Iceland, Germany, and Finland than in other nations.
How is TPP1-related Neuronal Ceroid Lipofuscinosis treated?
There is no treatment for the underlying cause of TPP1-related NCL. Treatments can only address the symptoms as they arise. Various medications can be useful for treating seizures, poor muscle tone, sleep disorders, mood disorders, excessive drooling, and digestion. In some people, a feeding tube is also helpful.
What is the prognosis for a person with TPP1-related Neuronal Ceroid Lipofuscinosis?
The prognosis for people with TPP1-related NCL is generally poor. They will become blind and have severe mental deterioration. They will enter a vegetative state in childhood and become totally dependent on others to care for them. Death can occur between the ages of 6 and 40.