Can you provide more information? There are many types of white matter conditions, and depends on where in the brain the disease/condition is located.
The "white matter" is part of the brain, and there is a large range of symptoms that one can have with this type of disease/injury to the brain; tremors can certainly be part of this. I am not sure what "TIA" is?
Are you or someone you know experiencing any symptoms, or have received a diagnosis, or did you read about this somewhere, and you were curious?