Sensory dysfunction in SMA type 2 and 3 - adaptive mechanism or concomitant target of damage?

A high SNAP amplitude suggests sensory fibre hyperactivity, which may be based on overactivation of metabolic pathways as an adaptive mechanism in response to SMN protein deficiency with additionally coexisting small C- and A-delta fibre damage. SMA patients seem to have a concomitant, mild demyelinating process present at the early SMA stage.