Neuronal ceroid lipofuscinosis

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Neuronal ceroid lipofuscinoses (NCLs), also called Batten disease, are a group of inherited brain disorders. In NCLs, lipofuscin—an abnormal pigment made of fats and proteins—builds up inside nerve cells and other organs. This buildup damages cells and leads to progressive loss of movement, thinking, and vision.

Genetic causes and forms
- NCLs are caused by mutations in several different genes. The most common childhood forms are due to mutations in CLN1 (PPT1) or CLN2 (TPP1); other important genes include CLN3 (battenin). CLN4 is not linked to a single known gene.
- Most childhood NCLs are autosomal recessive: a child must inherit two defective gene copies (one from each parent). Carriers have one defective copy and usually no symptoms.
- Adult-onset NCL (ANCL) exists and can be autosomal recessive (Kufs disease) or, more rarely, autosomal dominant (Parry’s form). Adults often have different, slower-progressing symptoms.

What the disease looks like by age
- Infantile NCL (INCL): symptoms start in the first year. Early vision loss leads to blindness by about age 2; the disease progresses quickly, and many children do not survive past early childhood.
- Late-infantile NCL: typically begins between ages 2 and 4. Seizures and vision loss are common; many patients die by ages 10–12.
- Juvenile NCL (Batten disease): usually starts between 4 and 10 years. Vision loss, seizures, and cognitive/behavioral decline occur; death often in the 20s or 30s.
- Adult NCL (ANCL/Kufs): onset around age 30 or later; symptoms can be milder and progress at varying rates. Vision loss is less common in this form.

Diagnosis
- Vision problems can be an early sign, but an eye exam alone cannot diagnose NCL.
- Diagnosis usually combines medical history, eye and brain examinations, and genetic testing to identify the specific NCL gene involved.
- NCLs are now more often classified by the responsible gene rather than by age alone.

Treatment and care
- There is no cure for most NCLs, but treatments can help manage symptoms and improve quality of life.
- Seizures are treated with antiepileptic drugs. Physical, speech, and occupational therapies help people stay as independent as possible.
- In 2017, the FDA approved cerliponase alfa (Brineura) as the first disease-specific treatment. It is an enzyme replacement therapy for late-infantile NCL due to TPP1 deficiency (CLN2) and is given directly into the cerebrospinal fluid to slow the loss of walking and other decline.
- Other experimental approaches, such as gene therapy and stem cell therapies, are being studied, but are not widely available yet.

Incidence and history
- How common NCLs are varies by type and population. Some studies report incidences ranging from about 0.5 to 3.9 per 100,000 people in different countries.
- The condition has a long history of research and was named after researchers who described its forms and patterns over the years.

In short, NCLs are a family of inherited, progressive brain disorders caused by different gene mutations that lead to harmful pigment buildup in nerve cells. They typically begin in childhood with vision loss and later affect movement and thinking, with variety in how quickly the disease progresses. Some treatments can help manage symptoms, and a targeted therapy is available for a specific subtype.