My first neuro did send me right away for a brain scan, but that was to rule out MS which runs in my family. MRI's of my spine were on record as I had had back surgery 9 years earlier for sciatica due to two ruptured discs, and consequent arthritis of the spine which only flares up rarely.
Johns Hopkins re-did all the usual bloodwork including one of the Athena genetic tests for HNPP as I do have pinched nerves, and a two hour gtt. Blood tests showed nothing, but I was offered further Athena testing to try and determine which variant of CMT 2 it might be, as well as a spinal tap. I had a lengthy EMG /NCS and a skin biopsy at Hopkins as well. I refused further testing as it was likely to be unproductive, the neurologist there agreed with my decision. My condition is moderate to severe now, and slowly deteriorating, but there is no treatment, regardless of the findings.
I think that many people want as many tests as possible and find it difficult to be at peace with the idea that there is no treatment. I am not speaking of the many neuropathies that can be improved through lifestyle choices, but of those that are hereditary, which includes many described as idiopathic. The quest for a diagnosis can come to resemble the quest for the holy grail. Modern medicine has encouraged us all to believe that they always have an answer.