Long-term improvement of tremor and ataxia after bilateral DBS of VOP/zona incerta in FXTAS

Fragile X-associated tremor/ataxia syndrome (FXTAS) is an X-linked adult-onset neurodegenerative disorder that affects carriers of the fragile X mental retardation 1 (FMR1) gene premutation, which is a 55-200 CGG repeat expansion in the 5' untranslated region of the gene.1 The core symptoms of FXTAS are progressive intention tremor and cerebellar ataxia. These symptoms can be disabling and, when combined, severely reduce the patient's quality of life. Symptomatic control with medication has limited effects.1 Very few cases have been treated with deep brain stimulation (DBS), mostly in the ventrointermediate thalamic (VIM) nucleus. This treatment results in tremor improvement with either no benefit or worsening of the ataxia and balance.2-4 We present a patient who experienced long-term tremor control and ataxia improvement after chronic bilateral stimulation of the ventro-oralis posterior thalamic nucleus and zona incerta (VoP/ZI), which resulted in significant improvement in daily life activities.