Batten disease (Neuronal Ceroid Lipofuscinoses) is an inherited disorder of the nervous system that usually manifests itself in early childhood. It is named after the British paediatrician who first described it in 1903. Early symptoms of the disease are usually noted by parents or physicians that may notice a previously normal child beginning to develop vision problems or seizures. In some cases the early signs are subtle, taking form of personality and behavior changes, slow learning, clumsiness, or stumbling. Classified by age, there are four main forms of Batten disease, each genetically different: Infantile, which begins between the ages of 6 months and 2 years. Late infantile, which begins between the ages of 2 and 4. Juvenile, which starts between 5 and 9 years and adult, which generally occurs before the age of 40 and is the most rare.
Over time, those affected with Battens suffer mental impairment, worsening seizures, with progressive loss of motor skills and sight. Eventually, children with Batten disease/NCL become blind, bedridden, unable to communicate and presently is always fatal. Batten disease is not contagious or, at this time, preventable.
Childhood NCL’s are autosomal recessive disorders. That is, they only occur 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 1 in 4 chance of developing NCL. At the same time, each child also faces a 1 in 2 chance of inheriting just one copy of the defective gene. Individuals who have only one defective gene are known as carriers, meaning they do develop the disease, but they pass it on to their own children.
Batten disease and other forms of NCL are relatively rare, occurring in an estimated 2 to 4 of every 100,000 births is the U.S. These disorders are more common in Finland, Sweden, other parts of northern Europe, Newfoundland and Canada. Although NCL’s are classified as rare diseases, they often strike more than one person in a family that carries the defective gene. A family can be affected by one type of NCL only.
The defective gene responsible for Batten disease causes a 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 NCL 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.
The 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 biochemically to materials accumulated more slowly during the normal aging 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 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.
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