Yes, hypovitaminosis (deficiency) can result in MBD causing bone loss. The spasms can be caused by symptoms of MBD. Hypervitaminosis (toxicity) has similar symptoms with hypovitaminosis, but more than likely will be caused in deficiency of vitamins, improper ratio of calcium-phosphorus, inadequate nutrition in the frog. So no from my understanding, it will most likely result in deficiency and not toxicity.