In their first year of life children with juvenile NCL develop completely normally. The first signs generally appear with gradual loss of sight beginning around
the age of six. In one to three years this will lead to complete blindness.
Around the age of eight the first signs of mental deterioration appear. The children forget what they learned before, such as maths and writing. Because they are in full awareness of this development it often leads to dramatic personality changes. At the age of 11 speech becomes difficult, 2 years later they often lose the ability of holding a conversation completely. Alongside this there are first sights of movement loss and the little patients will soon becoming dependent on a wheel chair. Further symptoms are epilepsy and cardiological problems. By the time the child is twenty the disease will have reached a stage where nearly all abilities had disappeared.
The NCL patient will lose control of all their bodily functions, must be nourished artificial and it has to be taken care of them 24 hours a day. Before they reach their 30st year of life death is caused by dehy-dration or respiratory paralysis. In Germany around 700 children are affected by jNCL, worldwide around 70,000.
The juvenile form of NCL is caused by an error in genetic material, which is a recessive gene. The affected gene lies on chromosome 16. This genetic mutation leads to fat like material collecting in the nerve cells because the natural metabolising protein is defective. The cells cannot clean themselves of pollutants of energy production, become dirty and later die. The eyes are the first affected organ - leading to blindness - followed shortly after by the brain.
NCL involves the mutation of one of 13 different NCL genes. They have the following symptoms in common: loss of sight, dementia, loss of motor functions and epilepsy. These differentiate themselves primarily be the age at which symptoms appear and in the speed with which the disease progresses. Most forms first show symptoms during childhood, but adults are also affected. All forms of child and youth NCL are autosomal recessively inherited.
The most common NCL-forms in Germany are the infantile NCL (CLN1, starts with 6 to 24 month), the late-infantile (CLN2, starts with 2 to 4 years) and the juvenile NCL (CLN3, starts with 5 to 20 years).
The one thing that all forms share is that they are currently incurable.
Due to the fact that depending on the type different genes are affected, not only one drug can be developed for all the forms of NCL. The NCL foundation focusses on the juvenile NCL. Actually there is one drug tested for NCL2 which seems pretty promising.
Before NCL is correctly determined it takes about two to four years and various consultations. To shorten this time and to avoid the high number of misdiagnoses it is necessary to inform ophthalmologists and pediatricians. Actually there are 13 known types of NCL. A gene test gives certainty if there is a mutation at the NCL gene which causes the disease.
For further information please contact Dr. Herman van der Putten.