Hi Snowathlete,
Lots of different studies, taken together indicate that people with CFS, FMS, ALS, MS, SupraNuclearPalsy, Alzheimer's, Autism, Parkinson's and probably some others all have low cerebral spinal fluid cobalamin levels, and some specifically also have been tested for MMA and HCY in the CSF. Various diseases have differening indications of which cobalamin is drastically low. I would hypothecize that there might be a genetic reason that it is either some kind of breakdown in transport into the CSF or it drains out too fast as some other research has suggested or both.