Batten disease is an inherited, neurodegenerative disease that primarily strikes infants, toddlers and school-aged children. Presently, there is no treatment, and it is always fatal.

Overview

Batten disease was first described in 1826. It is the common name for a group of diseases known as neuronal ceroid lipofuscinosis (NCL) and is one of the most common neurodegenerative diseases. It also belongs to a group known as lysosomal storage disorders. The symptoms of Batten disease are caused by the buildup of substances called lipopigments in the body's tissues. As these fatty substances continue to accumulate, they cause the death of specific cells, called neurons, in the brain, retina and central nervous system. At this time, there is no cure or viable treatment. It is not contagious or, at this time, preventable.

Batten disease is rarely diagnosed immediately and is often mistaken for epilepsy, mental retardation, retinitis pigmentosa or even schizophrenia in adults. Onset is characterized by beginning vision loss, seizures, clumsiness and personality and behavior changes. After onset, Batten disease causes continuing physical and mental deterioration, and affected children eventually become blind, bedridden and unable to communicate.

Batten disease is an autosomal recessive, inherited disease, meaning both parents must carry the defective gene in order for a child to be affected. A child that inherits just one bad copy could still pass the gene to his or her own children.

What are the forms of Batten disease?

There are four main types of NCL, including two forms that begin at an early age and a rare form that affects adults. The symptoms of each form are similar, but the age of onset and rate of progression vary.

• Infantile NCL (Santavuori-Haltia disease) begins before the age of 2 and progresses quickly. Children with Infantile NCL fail to thrive and have abnormally small heads (microcephaly). Short, sharp muscle contractions, or myoclonic jerks, are common. Initial symptoms include slowed psychomotor development that deteriorates with time, other motor disorders and seizures. Infantile NCL progresses the most quickly of all of the forms of Batten disease, and affected children live into their mid-childhood years.
• Late Infantile NCL (Jansky-Bielschowsky disease) begins between 2 and 4 years of age. Early signs typically include loss of muscle coordination, or ataxia, and seizures as well as progressive mental deterioration. This form progresses rapidly and usually ends in death between ages 8 and 12.
• Juvenile NCL (Batten disease) begins between the ages of 5 and 8. Early signs include progressive vision loss, seizures, ataxia and clumsiness. This form progresses relatively slowly and ends in death when affected children are in their late teens or early 20s, though some may live into their 30s.
• Adult NCL (Kufs disease or Parry’s disease) usually begins before the age of 40, causes milder symptoms that progress slowly, and does not cause blindness. Adult NCL does shorten life expectancy, though the life span of affected individuals varies widely.

There are six additional forms included in the Batten disease/NCL group:

• Finnish Late Infantile has been identified in Finland.
• Variant Late Infantile has been identified in Costa Rica, South America, Portugal and other nations.
• Turkish Late Infantile has been identified in Turkey.
• Northern Epilepsy/Epilepsy with Mental Retardation (ERMP) has been identified in Finland.
• Variant Juvenile has been identified in Germany and the United States.
• Congenital/CSTD has been identified in Europe.

How common is it?

Batten disease is relatively rare, occurring in an estimated two to four of every 100,000 births in the United States. The various forms of the disease occur worldwide. The NCLs are inherited, and although they are classified as rare diseases, they often strike more than one person in families that carry the defective gene.

How is it inherited?

The forms of NCL that occur in children are autosomal recessive disorders; in other words, they occur only when a child inherits two copies of the defective gene – one from each parent. When both parents carry one defective gene, each of their children faces a one in four chance of being affected with NCL and a one in two chance of being a carrier, meaning they can pass the defective gene on to their own children.

Adult NCL is usually inherited as an autosomal recessive disease (Kufs) but can also be inherited as an autosomal dominant disease (Parry’s). In the case of autosomal dominant inheritance, anyone who inherits a single copy of the defective gene is affected by the disease, and there are no unaffected carriers.

What causes it?

Symptoms of the various forms of NCL are linked to a buildup of substances called lipopigments in the body's tissues. These lipopigments are made up of fats and proteins. They accumulate in the cells of the brain and the eye as well as in skin, muscle and many other tissues. Inside the cells, these pigments form deposits with unique shapes that can be viewed under an electron microscope. Some look like half-moons or commas and are called curvilinear bodies, others look like fingerprints and are called fingerprint inclusion bodies and others look like gravel or sand and are called granual osmophilic deposits (grods).

The NCL diseases cause death of neurons, specific cells found in the brain, retina and central nervous system. The reason for neuron death is still not understood.

How is it diagnosed?

Because vision loss is often one of the early symptoms, Batten disease may first be suspected during an eye exam. Eye doctors can detect the loss of cells within the eye, which occurs in the three childhood forms of NCL. However, because such cell loss also occurs as a result of other eye diseases, an eye exam alone is not enough to provide a definite diagnosis.

An eye specialist or other doctor who suspects Batten disease may refer the child to a neurologist, a doctor who specializes in the brain and nervous system. A neurologist can use one or a combination of the following tests to pinpoint an accurate diagnosis:

• Skin or tissue sampling
• Electroencephalogram (EEG)
• Electrical studies of the eyes, including visual-evoked responses (VER) and electro-retinagrams (ERGs)
• Brain scans, including computed tomography (CT) and magnetic resonance imaging (MRI) scans
• Enzyme assay, a recent development and a quick and easy diagnostic test for Batten disease
• Genetic/DNA testing for diagnosis as well as carrier and prenatal status

Are treatments available?

Though current research is promising, there is not yet any known specific treatment that can halt or reverse the symptoms of the NCLs. However, seizures can be reduced or controlled with anticonvulsant drugs, and other medical problems associated with Batten disease can be treated as they occur. Physical and occupational therapy may help patients retain function later into the progression of the disease.

Some reports have indicated slowed progression in children who were treated with vitamins C and E and who maintained diets low in vitamin A. However, these measures did not prevent the fatal end result of the disease.