Here is an explainer on what Batten disease is from the National Institute of Neurological Disorders and Stroke.
Batten disease is the common name for a broad class of rare, fatal, inherited disorders of the nervous system also known as neuronal ceroid lipofuscinoses, or NCLs.
In these diseases, a defect in a specific gene triggers a cascade of problems that interferes with a cell’s ability to recycle certain molecules.
The disease has several forms that share some of the same features and symptoms but vary in severity and age when symptoms first begin to appear.
Each form is caused by a mutation in a different gene. Although “Batten disease” originally referred specifically to the juvenile-onset form of NCL, the term Batten disease is increasingly used to describe all forms of NCL.
Most forms of Batten disease/NCLs usually begin during childhood.
Children with the disease often appear healthy and develop normally before they begin to show symptoms.
Children with the infantile or late-infantile forms usually show symptoms earlier than age 1 year.
Common symptoms for most of the forms include vision loss, seizures, delay and eventual loss of skills previously acquired, dementia, and abnormal movements.
As the disease progresses, children may develop one or more symptoms including personality and behavior changes, clumsiness, learning difficulties, poor concentration, confusion, anxiety, difficulty sleeping, involuntary movements, and slow movement.
Over time, affected children may suffer from worsening seizures and progressive loss of language, speech, intellectual abilities (dementia), and motor skills.
Eventually, children with Batten disease become blind, wheelchair bound, bedridden, unable to communicate, and lose all cognitive functions.
There is no cure for these disorders but a treatment for one of the forms (CLN2 disease) has been approved by the U.S. Food and Drug Administration (see Treatment section).
Children with all forms of Batten disease have a greatly shortened life expectancy.
Generally, the increased risk for early death depends on the form of the disease and age of the child at disease onset.
Children with infantile Batten disease die prematurely, often in early childhood, while those with later-onset forms may live into their teens to their thirties.
If the disease develops in adulthood, the symptoms tend to be milder and may not affect life expectancy.
What causes Batten disease?
Batten disease is an inherited genetic disorder that appears to affect the function of tiny bodies within cells called lysosomes.
Lysosomes are the “recycle bin” of the cell and regularly break down waste, proteins, and naturally occurring fatty compounds called lipids into smaller components that can be discarded out of the cell or recycled.
Lipids include fatty acids, oils, waxes, and sterols.
In Batten disease/NCLs, the mutated genes do not produce the proper amounts of proteins important for lysosomal function.
Each gene (representing a form of the disease) provides information for a specific protein that is in turn, defective and not produced.
These proteins are needed for brain cells (neurons) and other cells to work efficiently.
The lack of a functional protein causes the abnormal buildup of “junk” material in the lysosomes—as well as the abnormal buildup of the residue called lipofuscin that occurs naturally as part of the lysosomal breakdown of lipids.
It is not known whether the lipofuscin itself is toxic or if the buildup is a marker of impaired lysosomal function.