Juvenile Batten disease is a rare, inherited neurodegenerative disorder. The most common form of Batten disease, also known as neuronal ceroid lipofuscinoses (NCL), juveline Batten is sometimes referred to as CLN3 disease or Spielmeyer-Vogt-Sjogren-Batten disease.
Causes
Juvenile Batten disease usually develops between the ages of 5 and 10. It is caused by mutations in the CLN3 gene, which provides instructions to make a protein called battenin.
Like other forms of the disorder, juvenile Batten disease is characterized by the buildup of a fatty substance, known as lipofuscin, within lysosomes. Mutations in the CLN3 gene lead to a reduction in the amount of functional battenin, which is found in the membranes of lysosomes and endosomes. These are compartments within the cell that break down substances that are no longer needed. Lipofuscin accumulation occurs in many cell types within the body, but brain cells are particularly sensitive, leading to neurological decline.
The exact function of battenin is not known, and it is not understood how the protein’s deficiency contributes to the problems associated with juvenile Batten disease.
The condition is inherited in an autosomal recessive way, meaning the disease only develops if both copies of the CLN3 gene — one inherited from each biological parent — are mutated.
Symptoms and prognosis
One of the early signs of juvenile Batten disease is impaired vision, usually occurring between ages 4 and 8. Vision changes rapidly, and might be completely lost by late childhood or adolescence.
Around the same age, children start having difficulties concentrating and learning new information. They also lose previously acquired skills and have problems speaking in complete sentences.
During adolescence, individuals with the disorder develop movement abnormalities in which muscles become rigid and stiff, causing them to move slowly and have a stooped posture. Eventually, patients lose the ability to walk independently and require a wheelchair.
In rare cases, patients develop heart problems during adolescence or early adulthood, including an increase in the size of the heart muscle, a condition known as hypertrophic cardiomyopathy, and heart rhythm issues.
At around 10 years old, seizures start to occur, the first of which are usually generalized motor seizures, also called tonic seizures, characterized by stiff muscles, loss of consciousness, and jerking movements. Later on, different types of seizures may develop, which may change over time.
Juvenile Batten disease patients usually live until their late teens or early 20s, although some individuals may live longer.
Treatment
There currently is no cure for juvenile Batten disease. Thus, available treatments focus on easing its symptoms.
Seizures can be controlled with anticonvulsants. Because the types of seizures change over time, patients usually receive more than one kind of anticonvulsant over the course of their disease.
Gene therapy, which involves the delivery of the functional CLN3 gene to the patient’s body using a harmless virus, and stem cell therapy, or a transplant of healthy human stem cells that have the intact CLN3 gene, are experimental therapies in development for the treatment of juvenile Batten disease.
An investigational therapy called BBDF-101, intended to slow progression of the disease, recently was approved to be studied in clinical trials. This treatment is designed to promote the disposal of cellular waste products that build up over the course of the disease.
Last updated: Oct. 8, 2021
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