Nigrostriatal involvement in ataxia with oculomotor apraxia type 1

Ataxia with oculomotor apraxia type 1 (AOA1) is a rare autosomal recessive neurodegenerative disease, recently associated with mutations in the aprataxin gene. Main features are early onset cerebellar ataxia, oculomotor apraxia and peripheral neuropathy. The presence of choreoathetosis or dystonia in some patients suggests basal ganglia involvement, but these structures appear preserved in a single case in which neuropathological examination was performed. To evaluate in vivo the nigrostriatal function we studied dopamine transporter (DAT) density with [(123)I] 2beta-carbometoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FPCIT)-SPECT in four AOA1 patients and eight healthy volunteers. All patients showed ataxia and neuropathy; only one had chorea and none had dystonia. Comparing with controls, AOA1 patients showed a slight reduction of the average striatal DAT density, which was bilateral and uniform in caudate and putamen. Nigrostriatal impairment occurred even in the absence of extrapyramidal features. Our data suggest subclinical involvement of basal ganglia in AOA1.