I agree that this sounds like a calcium deficiency and/or a neurological issue caused by bad or inadequate lighting...if you have a large, 70-gallon glass tank with a mesh lid, then you need to be sure that the T5 UVB tube is not on top of a mesh lid to the tank, and also that it's at least within 11" of his Basking Spot/Platform, and that the tube fixture that the UVB tube is in doesn't have any type of clear, plastic cover on it that goes over the UVB tube, as any type of plastic or glass blocks 100% of the
UVB light emitted by the tube, and the mesh lid blocks about 40% of the
UVB light. So if you have it on top of a mesh lid, and it's a very tall tank and it's further away from him than 11", then he's got a severe Calcium deficiency due to a lack of
UVB light.
Also, do you mean that you had not been giving him any calcium or multivitamin powders prior to this vet visit? Ever? That will also do it, you need to dust his live insects in a calcium powder 5 days a week and a multivitamin powder 3 days a week as an adult, and this along with an adequate, strong UVB tube that is mounted correctly will ensure that he will grow properly and not have a calcium deficiency or a Vitamin B1 (thiamine) deficiency...
What brand and length of T5 UVB tube do you have? I'm just asking because you didn't mention a brand, but you mentioned that you use "Reptisun" basking bulbs...also, what color Reptisun basking bulbs are you using? Are they white/yellow, or are they a color, like red, blue, etc.? And are they just regular, compact basking bulbs, or are they coiled/spiral basking bulbs?