Cross-sectional and longitudinal analysis of an oxidative stress biomarker for spinal and bulbar muscular atrophy.

ABSTRACT

INTRODUCTION: Spinal and bulbar muscular atrophy (SBMA) is an adult-onset motor neuron disease caused by a CAG repeat expansion in the androgen receptor gene. The aim of this study was to verify whether urinary 8-hydroxydeoxyguanosine (8-OHdG), an oxidative stress marker, is a biomarker for SBMA. METHODS: We measured the levels of urinary 8-OHdG in 33 genetically confirmed SBMA patients and 32 age-matched controls over a 24-month period at 6-month intervals. RESULTS: Urinary 8-OHdG levels in SBMA patients were significantly elevated compared with those of controls and correlated well with motor function scores. During the follow-up period, urinary 8-OHdG levels increased and correlated with motor function at each time-point. In addition, urinary 8-OHdG levels at baseline were correlated with changes in the 6-minute walk test during 24 months. CONCLUSIONS: Urinary 8-OHdG is a biomarker for SBMA, reflecting the severity and possibly predicting the deterioration of motor function.