no this is still a bit of a mystery. the most likely diagnosis is spinal muscular atrophy , i.e a problem with the anterior horn cells in the spinal chord.

it seems that normal nerve conduction velocities but denervation and normal csf , brain and spinal mri and normal blood workup including ck and transmines point to a problem in the cells of the spinal chord. the waters are muddied somewhat as in her case there now is axonal damage and demyleination, we know this from the nerve biopsy that was recently taken.

it seems that this axonal damage can happen as a result of the anterior horn cell problem, it is all very confusing.