Hereditary white matter disorders - Unclassified
There are many known white matter disorders that may occur in children. In most of these, not only the clinical presentation of the disease is known, but also its cause. It is surprising that there are still so many children with evident abnormalities of the white matter of the brain on MRI in whom the cause for the disease cannot be found. These are called "the unclassified white matter disorders". It is estimated that presently over 50% of the children remain without a classifying diagnosis.
No diagnosis - what's next?
When it is not possible to establish a diagnosis in a child with a white matter disorder, the parents are confronted with a child that has neurological problems, sometimes increasing problems, while they have no information about the future of their child, there is no causal treatment, and genetic counseling is not possible. For parents this is, of course, a dreadful situation.
Defining 'new' diseases
Since a few years we have a special clinical and research program for the unclassified white matter disorders and we have been successful in identifying several "new" white matter disorders. "New" is used in the sense that the disease is not described before. Of course, the disorder already existed.
The analysis of an unclassified progressive hereditary white matter disorder follows a distinct path. In our center it starts with the analysis of the medical history, all laboratory data and in particular the data from MR imaging and MR spectroscopy. In our database we search for comparable cases. For this last purpose it is necessary to collect as many unclassified cases as possible, because most of these disorders are extremely rare. The collection of a sufficient number of patients enabling the recognition of a new, specific entity takes time, effort, and the help of patients, parents and colleagues worldwide. Collaboration with other sides and with parent organizations is therefore very important.
Finding the cause....
Once a number of patients are identified with apparently the same disease, the next step will be to start a search for the common basic defect. When there is no biochemical abnormality as a lead, we will start a genetic study. Blood samples are collected of all families willing to participate. As soon as a sufficient number is samples is available, a search is performed to identify the responsible gene and the abnormal protein it produces. In these last few lines lies a tremendous amount of work, demanding sophisticated expensive equipment and experienced researchers.