The clinico-pathological study of a new type of familial parkinsonism with 
striatal degeneration is reported. The inheritance mode was autosomal recessive, 
and three out of four offspring of married cousins developed parkinsonism in 
their early adulthood. Their clinical signs were rigidity, bradykinesia, 
postural instability and dysarthria. These symptoms were slowly progressive and 
responsive to levodopa therapy to a variable degree. On cerebral magnetic 
resonance imaging, T2 and proton density-weighted images showed hyperintensity 
in the bilateral putamina. The neuropathological study of one case revealed 
atrophy of the bilateral putamina and caudate nuclei, and a severe neuronal loss 
and gliosis in the putamina. Patchy mosaicism of normal and degenerated tissue 
was observed in the putamina. A similar mode of the degeneration was mildly seen 
in the caudate nuclei. The substantia nigra showed atrophy of the pars 
reticulata, and mild to moderate neuronal loss of the pars compacta with rostral 
dominance, but no Lewy bodies were observed. These neuropathological findings 
differed from those of Parkinson's disease or juvenile parkinsonism, but mimic 
to those of X-linked dystonia parkinsonism (Lubag). It seems that this familial 
bilateral striatal degeneration is a new variant of familial parkinsonism.