The beneficial effects of histone deacetylase inhibitors in spinal muscular atrophy mice are independent of follistatin induction, as overexpression of follistatin without histone deacetylase inhibition does not improve survival or motor function despite increased follistatin expression.

In spinal muscular atrophy, a lack of SMN protein causes motor neurons and muscle fibers to deteriorate, leading to weakness and early death. Even when the body tries to fix muscle loss by increasing follistatin or blocking myostatin, these changes do not stop the nerve and muscle damage. The real problem is not muscle size, but the failure of nerves to properly connect with and sustain muscle fibers.