PRESYNAPTIC NIGROSTRIATAL FUNCTION IN GENETICALLY TESTED ASYMPTOMATICRELATIVES FROM THE PALLIDO-PONTO-NIGRAL DEGENERATION FAMILY

Pallido-ponto-nigral degeneration (PPND) is a dominantly inherited dis order with parkinsonism. We performed PET with [F-18]fluorodopa (FD) a nd, later, gene testing in 12 asymptomatic relatives at risk from a fa mily with PPND and compared the striatal FD uptake constant (K-i) in t hem with 4 symptomatic individuals and 10 normal control subjects. Fou r relatives with positive linkage had a significantly reduced K-i from the normal control subjects but to a lesser degree than the symptomat ic patients. The mean K-i in the relatives with negative Linkage (n=8) did net differ from normal control subjects. In conclusion, we identi fied reduced dopaminergic function in asymptomatic relatives with posi tive genetic linkage from the PPND family. Most of the reduction in th is disorder occurs in the fifth decade, when the disease manifests cli nically.