About Batten Disease
Batten Disease is a rare genetic disorder that belongs to a group of progressive degenerative metabolic conditions known as neuronal ceroid lipofuscinoses or NCL. Occasionally it may be referred to as a type of progressive myoclonic epilepsy but this can cause a great deal of confusion as the condition has more symptoms than seizures alone. More accurately, it also falls under the category of lysosomal storage diseases.
There are four main types of NCL, including two forms that begin earlier in childhood and a very rare form that strikes adults. The symptoms are similar but they become apparent at different ages and progress at
Infantile NCL - 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. Initial signs of this disorder include delayed psychomotor development with progressive deterioration, other motor disorders, or seizures. The infantile form has the most rapid progression and children live into their mid childhood years.
Late Infantile NCL - begins between ages 2 and 4. The typical early signsare loss of muscle coordination (ataxia) and seizures along with progressive mental deterioration.. This form progresses rapidly and ends in death between ages 8 and 12.
Juvenile NCL - begins between the ages of 5 and 8 years of age. The typical early signs
are progressive vision loss, seizures, ataxia or clumsiness. This form progresses less rapidly and ends in death in the late teens or early 20s, although some may live into their 30s.
Adult NCL - generally begins before the age of 40, causes milder symptoms that progress slowly, and does not cause blindness. Although age of death is variable amongaffected individuals, this form does shorten life expectancy.
Batten Disease/NCL is relatively rare, occurring in an estimated 2 to 4 of every 100,000 births in the
United States. The diseases have been identified worldwide. Although NCLs are classified as rare
diseases, they often strike more than one person in families that carry the defective gene
*I personally have found this statistic to be quite misleading. At any given time there are less than 200
children in North America with Batten Disease, with the Juvenille subtype having the highest prevalence.
How are NCLs inherited?
Childhood NCLs are autosomal recessive disorders; that is, 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 25% chance of developing NCL. At the same time, each child also faces a 50% chance of inheriting just one copy of the defective gene. Individuals who have only one defective gene are known as carriers, meaning they do not develop the disease, but they can pass the gene on to their own children.
What causes these diseases?
Symptoms of Batten Disease/NCLs are linked to a buildup of substances called lipopigments in the
body's tissues. These lipopigments are made up of fats and proteins. Their name comes from the
technical word lipo, which is short for "lipid" or fat, and from the term pigment, used because they take on a greenish-yellow color when viewed under an ultraviolet light microscope. The lipopigments build up in 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 distinctive shapes that can be seen under an electron microscope. Some look like half-moons (or comas) and are called curvilinear bodies, others look like fingerprints and are called fingerprint inclusion bodies and still others resemble gravel (or sand) and are called granualosmophilic deposits (grods). These deposits are what doctors look for when they examine a skin sample to diagnose Batten Disease.
The diseases cause death of neurons (specific cells found in the brain, retina and central nervous
system). The reason for neuron death is still not known.
*Info taken from Batten Disease Research and Support Association www.bdsra.org
Are you confused yet? Since the above information can be difficult to understand, I use a much simpler analogy when explaining to to Tatyanna's little sister and classmates at school. Essentially, with Battens it's like the garbage collectors in her brain have gone on strike. When Tatyanna was young, she didn't produce much garbage and it took a while before things really started to build up. This is why children are born with no symptoms. As the garbage starts to increase symptoms start to appear. In Tatyanna's case it wasn't until the summer that she was 4 that we started to notice that things weren't quite right. Eventually the garbage increases to the point where the brain can no longer function. The rate at which garbage accumulates depends on the NCL type as well as the individual child.