There are several scientific papers, mostly from Japan, that point to sodium butyrate as a possible treatment for SBMA or Kennedy's disease. For example:

Pathogenesis-targeting therapeutics for spinal and bulbar muscualar atrophy (Suzuki, 2009).
Therapeutic strategies for spinal and bulbar muscular atrophy (Katsuno, 2007).
Sodium butryate ameliorates phenotypic expression in a transgenic mouse model of spinal and bulbar muscular atrophy (Minamiyama, 2004).

(You can find the originals of these papers by cutting and pasting the title and author into an Internet search tool such as Google.)

So, it may be worthwhile to start a thread on the subject of butyrate. If you have news on it, hear of clinical trials involving it, or have tried taking it, please post here. Thanks.