Juvenile Batten disease is an inherited disorder that primarily affects the nervous system. After a few years of normal development, children with this condition develop progressive vision loss, intellectual and motor disability, speech difficulties, and seizures.
Most cases of juvenile Batten disease are caused by mutations in the CLN3 gene. This gene provides instructions for making a protein whose function is unknown.
It is unclear how mutations in the CLN3 gene lead to the characteristic features of juvenile Batten disease. These mutations somehow disrupt the function of cellular structures called lysosomes. A small percentage of cases of juvenile Batten disease are caused by mutations in other genes. Many of these genes are involved in lysosomal function, and when mutated, can cause this or other forms of neuronal ceroid lipofuscinoses.