Saccadic Abnormalities in Familial Parkinson's Disease Associated with -Synuclein (SNCA) Gene Mutation (PARK1) (P02.258)

Abstract

Objective: To investigate saccadic characteristics of PARK1 and to compare them with those of other parkinsonian syndromes. Background Typical patterns of eye movement abnormalities have been described in both idiopathic (PD, CDB, LBD and MSA) and familial (PARK2 and PARK6) parkinsonian syndromes, providing not only useful diagnostic markers, but also insights in to the functions of the basal ganglia. Mutations in the SNCA gene are a rare cause of autosomal dominant early-onset Parkinson9s Diseases (PARK1); its gene product is the main component of Lewy bodies, the hallmark of parkinsonian neuronal degeneration. Design/Methods: Two symptomatic PARK1 patients were recorded during various saccadic paradigms: horizontal visually-guided saccades (VGS), anti-saccades, overlap, and memory-guided saccades (MGS) (10° and 18°). Data were statistically compared with those of 19 healthy controls. Results were related to findings reported in other parkinsonian syndromes. Results: Both patients showed saccadic abnormalities. VGS amplitude (10° p1:9.6±0.8°, p2:8.4±0.5° normal values (n.v.) 10.3±1.0° p Conclusions: PARK1 patients present peculiar abnormalities in both voluntary and reflexive saccades. Hypometric VGS, abnormal inhibition of reflexive saccades and staircase saccades have been described in other parkinsonian syndromes. The observation of slow VGS has never been reported in parkinsonian syndromes and may indicate the extension of the neuronal degeneration to other structures controlling saccade dynamics. The characteristic patterns of saccade abnormalities may help diagnosis as well as pointing to an understanding of the functions of the basal ganglia and how they become impaired in parkinsonian syndromes. Disclosure: Dr. Pretegiani has nothing to disclose. Dr. Leigh has nothing to disclose. Dr. Zee has received royalty payments from Oxford University Press. Dr. Federico has nothing to disclose. Dr. Piu has nothing to disclose. Dr. Rufa has nothing to disclose.