Batten disease describes a group of related conditions, all collectively known as neuronal ceroid lipofuscinoses (NCLs), that can manifest with seizures, vision loss, and progressive cognitive and motor problems. Knowing which type of Batten a patient has may provide information on disease progression and potential treatment options.
The disease is characterized by a buildup of insoluble waste deposits called lipofuscins inside cells, which interferes with normal cellular function and eventually leads to cell death.
Since nerve cells are particularly sensitive to the toxic effects of waste accumulation, people with Batten may experience symptoms such as seizures and motor problems, as well as vision loss, and progressive cognitive difficulties.
Based on age range and severity of symptoms, Batten disease is divided into several types.
The disorder is commonly divided into five main categories: congenital, infantile, late infantile, juvenile, and adult Batten disease. All of these types are caused by mutations in 14 different genes, referred to as CLN1 through CLN14.
Some mutations cause certain enzymes to be absent or deficient, while others produce defective proteins needed for nerve cells and other cells to work properly.
Congenital Batten disease
Congenital Batten disease, also known as CLN10 disease, is an extremely rare type caused by a defect in the CLN10 (or CTSD) gene, which provides instructions for making an enzyme called cathepsin D. Most symptoms develop from birth and include severe breathing issues resulting in respiratory failure, unusual muscles stiffness, and persistent seizures that last several minutes (status epilepticus).
Infantile Batten disease
Infantile Batten disease is sometimes referred to as CLN1 disease and is caused by a mutation in the PPT1 (or CLN1) gene that provides instructions to produce the PPT1 (palmitoyl-protein thioesterase 1) enzyme. Symptom onset generally occurs between 2 and 24 months (2 years) of age.
At earlier stages, children often fail to reach normal cognitive and motor development goals. Other symptoms include sudden involuntary jerks or twitches, seizures, and decreased muscle tone.
Late infantile Batten disease
Late infantile Batten disease occurs in children, typically starting during the ages 2 to 4, and is characterized by loss of vision, motor and intellectual skills, seizures, and a reduced life expectancy.
This type is also referred to as CLN2 disease as it may be caused by mutations in the CLN2 gene. When mutations occur in the CLN2 gene, the disease is usually called classic late-infantile Batten and is due to defects in the production of a lysosomal enzyme called tripeptidyl peptidase1 or TPP1.
However, mutations have also been identified in the CLN1, CLN5, CLN6, CLN7, and CLN8 genes.
Juvenile Batten disease
Juvenile Batten disease, sometimes referred to as CLN3 disease, is the most common form of Batten and is caused by mutations in the CLN3 gene, which provides instructions to make a protein called battenin. This type of Batten disease usually develops in children between the ages of 5 and 10.
Early symptoms include vision impairment, speaking and learning problems. Later on, children can experience muscle stiffness and seizures, and may lose the ability to walk independently. In rare occasions, patients develop heart problems during adolescence or early adulthood.
Adult Batten disease
Symptoms of adult Batten disease usually begin when patients reach their 30s, but they can develop earlier in adolescence or over age 50.
Adult Batten disease may be divided into two forms, type A and type B.
Type A is caused by defects in either the CLN1 or the CLN6 gene. Patients with this form often have seizures with uncontrollable jerky movements (myoclonus), tics or tremors, poor coordination (ataxia), and difficulty speaking.
Type B adult Batten disease is caused by mutations in either the CTSF gene (CLN13 disease) or the DNAJC5 gene (CLN4 disease). It is marked by behavioral abnormalities, and possibly dementia. Many of the symptoms are similar to those of type A. However, people with type B are less likely to develop speaking issues or myoclonic seizures.
Epilepsy with progressive mental retardation (CLN8 disease variant)
Epilepsy with progressive mental retardation (EPMR), sometimes referred to as Northern Epilepsy syndrome, is a less severe form of CLN8 disease. The more severe form is a variant of the late-infantile Batten disease. Both subtypes are caused by mutations in the CLN8 gene.
The first signs of EPMR appear between ages 5 and 10 and include seizures, intellectual failure, and behavioral changes. Seizure frequency tends to increase until puberty, at which point cognitive deterioration will become more rapid. However, the number of seizures tends to decrease spontaneously after puberty.
Some patients may lose the ability to speak. Overall, individuals with EPMR have a longer life expectancy when compared with other types of Batten disease.
CLN9 disease is a variant of Batten disease clinically similar to the juvenile type. Although the gene responsible is yet to be identified, CLN9-deficient cells have diminished sphingolipids a type of fat molecule that impacts cell death, growth, and differentiation.
Symptoms of CLN9 disease generally appear in children at around age 4 and may include poor coordination (ataxia), seizures that do not respond to medications, vision loss, and cognitive decline.
Last updated: Oct. 13, 2021
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