It would be very useful to you to check with your breeder and inquire about any family history of epilepsy, as well as inquiring about the status of your pup s littermates. There are several board-certified veterinary neurologists available to assist in this workup if needed. If no cause was determined for the seizure and your pup has had no further episodes, it might be prudent to just wait. We have seen several pups who seizured once and never repeated the episode. We should also mention that a diagnosis of epilepsy is not a death warrant.
Many epileptic dogs are well-controlled on anticonvulsent medication.
Best of luck with your puppy. This produces progressive widespread nerve degeneration. I have seen reports of this rare condition in cats, but not in dogs. The symptoms described in one Siamese cat were rear leg weakness progressing eventually to affect the forelegs as well. Definitive diagnosis involves complicated enzyme tests.