PPT1-related neuronal ceroid lipofuscinosis (NCL) is a disorder that leads to the degeneration of the brain, causing a progressive loss of intellectual abilities and motor skills.
It also results in blindness, seizures, and often leads to an early death. NCL has different forms, mainly based on the gene responsible and when symptoms start. Mutations in the PPT1 gene typically lead to either the infantile or juvenile form of NCL.
The infantile form (INCL) usually shows symptoms between 6 and 24 months of age. Initially, infants may have developmental delays, jerking movements, and/or seizures. They often have small heads. By 24 months, blindness and seizures develop, followed by a decline in cognitive functions. Movement becomes spastic and uncontrolled, leading to a loss of motor skills and intellectual abilities.
Juvenile NCL (JNCL), also known as Batten disease, typically starts between ages 4 and 10. Children rapidly lose vision, often the first noticeable symptom, becoming completely blind within two years. Seizures usually begin between ages 5 and 18, with declining cognitive functions between 8 and 14. Childhood may bring speech and behavioral problems, psychiatric issues, and later, dementia or memory problems. Motor function declines, and controlling body movements becomes challenging.
There is no cure for the underlying cause of PPT1-related NCL. Available treatments focus on managing symptoms as they appear. Medications can help with seizures, movement issues, sleep difficulties, mood disorders, excessive drooling, and digestive problems. Some individuals may benefit from a feeding tube.
This condition is caused by pathogenic (disease-causing) variants in the PPT1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.