Batten Disease
- Batten disease is a broad class of rare and fatal genetic disorders of the nervous system.
- This disorder affects the body’s ability to get rid of cellular wastes like lipids, sugar, and proteins which build up in the cells, causing problems for the nervous system.
- It affects both children and adults who are usually unaware of it until they have developed worsening symptoms.
Symptoms
- The symptoms range in severity and can start at any age right from infancy or sometimes later in childhood and they can also start in adulthood.
- Some early symptoms include seizures, dementia, worsening eyesight, behavior, and learning problems.
- As the disease progresses, the symptoms worsen to include sleep concerns, muscle spasms, mood or behavior changes, and gross motor issues, among others
Causes
- Batten disease is a hereditary disorder that is usually passed down from parents to their child.
- It happens when both parents are carriers of a mutated gene.
- This gene is usually autosomal recessive meaning that it doesn’t cause symptoms unless a person inherits the disease-causing gene from both parents.
- So if a person has only one copy of the gene, they would not have symptoms but will only be carriers.
Types
There are 13 types of batten disease and they are each classified according to the affected gene. They can also be classified based on the age of onset, symptoms, severity, and the rate at which the symptoms worsen. They include:
- CLN1 which is classified into the infantile and juvenile-onset with symptoms like inability to stand, walk or talk.
- CLN2 is classified into late infantile and juvenile-onset with symptoms like seizures, trouble walking, and talking. Symptoms like ataxia and loss of coordination occur in the juvenile-onset
- CLN3 occurs in children between 4 and 7 years who rapidly lose their eyesight. They may have other symptoms like seizures, and learning and behavior issues.
- CLN4 is a rare subtype that only occurs in adulthood with symptoms like dementia and movement issues.
- CLN5 where children develop few symptoms in the first life of their years. Other symptoms appear later on.
- CLN6 is classified into the late infantile and adult-onset. Seizures and developmental delays are symptoms of late infantile onset. The adult-onset affects muscle control in the arms and legs and there’s also a slow cognitive decline.
- CLN7 is marked by seizures and loss of developmental skills. Other symptoms develop when the child is between 9 and 11 years.
- CLN8 is classified into the juvenile and late variant onset. In the juvenile-onset, children experience epilepsy with progressive mental retardation. Primary symptoms of the late variant onset are vision loss, cognitive issues, and many others.
- CLN10 is a very rare subtype where children may have a small head. It is classified into congenital and late infantile onset.
Diagnosis
- Batten disease is most commonly diagnosed using genetic testing.
- Other tests used for the diagnosis include enzyme activity measurements, skin or tissue sampling, and blood or urine testing.
- To diagnose and monitor the effects of the disease, electroencephalogram, and imaging tests are done.
Treatment
- There is no cure for Batten disease and treatment cannot reverse the progression of the disease.
- Instead, it focuses on addressing symptoms and improving quality of life.
- The food and drug administration has approved a treatment for the CLN2 subtype and it is just this subtype and no other.
- The treatment is an enzyme replacement therapy named ‘cerliponase alfa’ which slows or even stops the progression of this subtype.
- Other treatments include antiseizure medications, depression or anxiety medications, medications to treat spasticity, physical therapy, and occupational therapy