There are four main types of NCL, including a very rare form that affects adults. The symptoms of all types are similar, but will become apparent at different ages, and will progress at different rates.

• Infantile NCL: (Santavuori-Haltia type) begins between about 6 months and 2 years of age and progresses rapidly. Affected children fail to thrive and have abnormally small heads (microcephaly). Also typical are short, sharp muscle contractions called myoclonic jerks. Patients usually die before age 5, although some have survived a few years longer.
• Late infantile NCL: (Jansky-Bielschowsky type) begins between ages 2 and 4. The typical early signs are loss of muscle coordination (ataxia) and seizures that do not respond to anticonvulsant drugs. This form progresses fairly rapidly and children live to between the ages 6 and 12.
• Juvenile NCL: (Spielmeyer-Vogt-Sjogren Batten type) begins between the ages of 5 to 10. The most frequent beginning symptom is visual failure, less common are seizures. Motor disturbances occur late in the disease. After a slowly progressive course patients usually live to late teens, early '20s or more rarely, into their 30's.
• Adult NCL: (Kufs or Parry's type) generally begins before the age of 40, causes milder symptoms that progress slowly, and does not cause blindness. Although age of death is variable among affected individuals, this form does shorten life expectancy.
• Other Types: Some children who definitely have Batten Disease do not fall into any of the patterns described above. About 1 in 10 cases are not typical of any of these groups of children. In some, the disease progresses more quickly. In others, more slowly.

Please download these information leaflets from the BDFA (Batten Disease Family Alliance), our charity affiliate in the UK.

• Infantile
• Late Infantile
• Juvenile

The nucleus of every cell in the body contains twenty-three pairs of chromosomes. Each gene represents the 'code' for a particular characteristic. In the case of Batten Disease, there is an aberration in one of the genes in one pair of chromosomes.

Childhood NCLs are autosomal recessive disorders, that occur when a child inherits two copies of the defective gene, one from each parent. When this occurs, each of their children has a one in four chance of developing NCL or a one in two chance of inheriting just one copy of the defective gene. Individuals who have only one defective gene are known as carriers. They do not develop the disease, but they can pass the gene on to their own children.

Although there is no conclusive test yet available to identify carriers of the affected gene, recent breakthroughs in identification of the infantile and juvenile types have brought this one step closer. Adult NCL may be inherited as an autosomal recessive or, less often, as an autosomal dominant disorder. In autosomal dominant inheritance, all people who inherit a single copy of the disease gene develop the disease. As a result, there are no unaffected carriers of the gene.

The defective gene causes malfunction at a cellular level. This is manifested in a number of different ways which affect the cell chemistry and leads to a variety of clinical observations and symptoms. The exact procedure in the different types of NCLs is still not understood. One theory holds that the disease reflects a disorder of the normal degradation of membranes within neurons, leading to an abnormal disposal and accumulation of insoluble lipid-protein complexes. Another theory claims that the disease may be characterised by a disorder in lipid metabolism in the cells; i.e. lipids or fats, and their associated proteins are not processed correctly.

Research suggests that there is an abnormal production of lipid peroxides and an enzyme deficiency, probably among specific enzymes that digest membrane proteins.

This combination of problems leads to the accumulation of a yellow fluorescent pigment, ceroid lipofuscin, in the brain cells. At this time, the pigment is considered to be the end result of a combination of metabolic derangements and marks the progressive deterioration in brain function.

The ceroid pigment is similar bio chemically to materials accumulated more slowly during the normal ageing process. In Batten Disease, however, the accumulation is quite rapid and destructive. The specific reasons for the loss in brain function are not known. Thus, while there are some promising leads, and some very recent breakthroughs in gene research, we still have little understanding of the specific cause or biochemical mechanism involved in Batten Disease.

Batten Disease is rarely diagnosed immediately because of the variability in symptoms and age of onset. Children are often mistakenly thought to have epilepsy or a form of mental retardation. Adults are sometimes labelled schizophrenics. This can be a difficult and frustrating time for all concerned.

Since vision loss is often an early sign, Batten Disease may be first suspected during an eye examination. A doctor can detect a loss of cells within the eye that occurs in the three childhood forms of NCL. However, because such cell loss occurs in other eye diseases, the disorder cannot be diagnosed by this alone. A doctor who suspects NCL may refer the child to a neurologist who specialises in diseases of the brain and nervous system.

In order to diagnose NCL, the neurologist needs the patient's medical history and information from various laboratory tests. Diagnostic tests used for NCLs include:

• Blood or urine tests. These tests can detect abnormalities that may indicate Batten Disease. For example, elevated levels of a chemical called dolichol are found in the urine of many NCL patients.
• Skin or tissue sampling. The doctor can examine a small piece of tissue under an electron microscope. The powerful magnification will show typical NCL deposits. These deposits are common in skin cells, especially those from sweat glands and samples may be taken from the skin or a rectal biopsy.
• Electroencephalogram (EEG). An EEG uses special patches placed on the scalp to record electrical currents inside the brain. This helps doctors detect tell-tale patterns in the brain's electrical activity.
• Electrical studies of the eyes. These tests, which include visual-evoked responses and electroretinograms, can detect various eye problems common in childhood NCLs.
• Brain scans . Imaging can help detect changes in the brain's appearance. The most commonly used imaging technique is computed tomography (CT) which creates a sophisticated picture of the brain's tissues and structures. Another technique is magnetic resonance imaging (MRI) which uses a combination of magnetic fields and radio waves to create a picture of the brain.

An accurate diagnosis of Batten Disease and the particular type is essential before prenatal or pre-symptomatic tests can be done.

• Carrier, prenatal and pre-genetic embryo (IVF) testing is available for the more common forms.
• Please liaise with your Consultant, Medical Practitioner and a Geneticist for information. Tests may need to be carried out overseas due to lack of some techniques in Ireland.
• Pre-symptomatic testing of younger children is possible using blood screening, a skin or rectal biopsy when the diagnosis in an older child has been confirmed with similar tests.

If you want to have other members of your family tested for being carriers, we advise you to approach your Consultant. This is a very difficult and stressful occasion. Support from family, friends and professional services can be beneficial.

As yet, no specific treatment is known that can halt or reverse the symptoms of Batten Disease. However, seizures can be reduced or controlled with anti-convulsion medication, and other medical problems can be treated appropriately as they arise. At the same time, physical and occupational therapy can help patients retain function as long as possible.

There are some medical trials and studies being carried out in the USA, UK, Australia, Germany and the Netherlands. Some reports have described a slowing of the disease in children with Batten Disease who received vitamin supplements. Attention is also being focussed on controlling some of the cell chemistry through dietary trials including fish oils and anti-oxidants. Thus far, however, these treatments have not prevented the final outcome of the disease.

Through the work of several scientific teams in different countries, the search for the genetic cause of NCLs is gathering speed. We have moved into the next decade of research since the first breakthrough of isolating the infantile gene.

Some scientists are investigating the theory that children with Batten Disease have a shortage of a key body enzyme. Investigators are searching for enzymes that might be scarce, defective, or completely missing.

Support and understanding can help patients and families cope with the profound disability and loss of cognitive function caused by NCLs. Often, support groups enable affected children, adults, and families to share common concerns and experiences. Bee for Battens is affiliated and networked with Batten Disease charities worldwide, and we can offer support and advice from experienced care providers and families globally.

Meanwhile, scientists continue to pursue medical research that could someday (hopefully in the near future), yield an effective treatment. More government and public support is needed to fund these initiatives.