Involvement of the spinal posterior horn in Gerstmann-Straussler-Scheinker disease (PrP P102L)

Objective: The authors studied the pathomechanisms of the characteristics associated with Gerstmann-Straussler-Scheinker disease (GSS). Background: GSS, associated with a missense mutation at codon 102 of the prion protein (PrP) gene (GSS102),is a hereditary disorder that presents with progressive ataxia and dementia, and is characterized by the loss of deep tendon reflexes and painful dysesthesias of the legs in its early stage. Methods: The authors conducted immunohistochemical studies of the spinal cord and peripheral nervous system in one of two patients from a Japanese family with GSS102 in comparison with patients with GSS105. Results: The authors found intense PrP immunoreactivities mainly in the posterior horn of the spinal cord, but not in the dorsal root ganglia or peripheral nerves. In addition to PrP amyloid plaques, synaptic-type, fine granular PrP deposits were distributed in the spinal posterior horns. In contrast to the GSS102 patient;, the spinal cords of the GSS105 patients showed no granular PrP deposits. Conclusions: The PrP abnormalities in synaptic structures of the spinal posterior horn may cause synaptic dysfunction that leads to loss of deep tendon reflexes and painful dysesthesias in patients with GSS102.