No effect of AR polyG polymorphism on spinal and bulbar muscular atrophy phenotype.

BACKGROUND AND PURPOSE: Disease severity varies considerably among patients with Spinal and Bulbar Muscular Atrophy (SBMA). Our aim was to investigate the role of androgen receptor (AR) polymorphic repeats in SBMA phenotype. METHODS: We analyzed the length of AR polyQ and polyG tracts in 159 SBMA patients. RESULTS: No relationship between polyG size or polyG/polyQ haplotypes and clinical phenotype was found. An independent negative correlation between polyQ-length and onset of weakness was confirmed (P < 0.001). CONCLUSIONS: The negative results of our study prompt to continue the search for potential disease modifiers in SBMA outside the AR gene.