What is this disease?

What is this disease?
Several months after the birth of a litter four of them started to move badly. In rest I would find them in there hiding place high in the terrarium. There were no deviations visibility or noticeable. However, during movement they moved themselves with the first (1/3) part of their body slightly slanted (with the head under an angle of approximately 30 degrees).

After about half a year I decided to put three out of four animals to sleep because they did not accept sufficient food. Number four however accepted all food offered. Without any difficulty she did eat mice of semi-adult size . With much fanaticism she would strike but miss. Clearly she missed the coordination in her movements. Sometimes so much that she would go on her back true the terrarium out of pure agitation (see photograph).
Apart from her problems in movement her tail shows deviations; coalescences and bulges (see photograph).

Marja Kik (the veterinary surgeon I consult if there problems with my animals) thought it might be a possible virus contagion. That made me decide to put this snake into quarantine. Shortage of vitamin B (complex) might be a possibility too although less obvious. During the period of quarantine the snake was treated with; Vitamin B-complex. Once by injection and during the next three months every month one capsule. Her condition did not improve and I did put her to sleep at the age of 10 months.

Any idea what kind of disease this is?
Please let me know..