Oops, sorry, of course OPCA shoeld be right - it's more common name of it's disorder, rather than cerebellar ataxia. However your type of tremor not like intentional tremor, thats link to the OPCA, but tremor can difirrent from various people.

Unknown type thats more bad than with known genetic mutation, becouse for it's cause require serach that gene is broken before the cure will be done. But take care, genetic test near future of the next two years, and unknown will clear.

Sorry for my english, can explain on russian, want you?