Batten disease is one of a group of diseases called neuronal ceroid lipofuscinoses, or NCLs. The term Batten disease was previously used to refer to a juvenile form of NCL but it has become increasingly common to refer to all forms of NCL as Batten disease.

Inheritance

Batten disease is inherited in an autosomal recessive fashion, meaning a child needs to inherit one copy of the defective gene for the condition form each of their parents in order to develop the disease. When both parents carry the defective gene, each of the children has a one in four chance of developing NCL.

Each child also has a one in two chance of inheriting just one copy of the defective gene. This would make them a carrier of the gene, which they may pass onto their children even though they never develop the condition themselves.

Pathology and symptoms of Batten disease

The symptoms of Batten Disease arise due to a build up of substances called lipopigments, composites of fat and protein, in the bodily tissues. The word "lipo," means lipids or fat and "pigment" refers to the greenish-yellow colour they exhibit under the ultraviolet light microscope.

These lipopigments accumulate in various tissues of the body including the retina, skin, muscles and central nervous system. They form deposits inside cells that can be viewed as distinctive half-moon shapes, fingerprint shapes or sand grain shapes. These NCL deposits damage neurons in the tissues, eventually leading to symptoms of the disease.

Symptoms

Batten disease usually develops during childhood between the ages of 5 and 10 years. Symptom onset may be obvious, with the child suffering from seizures or vision loss or it may be subtle, only causing mild personality changes or clumsiness.

Over time, symptoms progress and the patient begins to suffer form mental impairment, loss of vision, loss of motor skills and worsening seizures. Eventually, the child may become blind, bedridden and unable to communicate. By this stage, individuals are at risk of losing their lives. People who develop childhood forms of NCL do not usually live much beyond the age of 30 years.

Types of neuronal ceroid lipofuscinoses

There are four main types of NCL. These include:

• Infantile NCL - Also called Santavuori-Haltia disease, this is a severe form of the disease that starts to develop between 6 months and 2 years of age and is rapidly progressing. Affected children have unusually small heads (micorcephaly), fail to thrive and often suffer from short, sharp contractions or jerks. The condition progresses rapidly and children only live into their mid-childhood years.
• Late infantile NCL - Also called Jansky-Bielschowsky disease, this form starts to affects children at age 2 to 4 years. Typical early symptoms include loss of muscle control (ataxia), mental deterioration and seizures. Late infantile NCL also progresses rapidly and children usually die between the ages of 8 and 12.
• Juvenile NCL (Batten disease) - This form of the condition starts to develop between the ages of 5 and 8 years. The first signs of the condition often include clumsiness, vision loss, ataxia or seizures. This form progresses more gradually, with individuals usually dying in their late teens or early twenties, although some sufferers make it into their 30s.
• Adult NCL - Also called Kufs Disease or Parry Disease, this condition usually affects individuals before the age of 40. This form of NCL is slower to progress and symptoms are milder. Age at death varies somewhat but the condition does shorten lifespan.