The genetic defect in dentatorubral-pallidoluysian atrophy (DRPLA) is expansion 
of the CAG repeat. The mutant gene is translated into the protein which carries 
the expanded glutamine repeat. Immunoblots of human brain tissues with and 
without reduction show that the DRPLA protein is a disulfide-bond complex and 
that more of this complex is formed in DRPLA brains than in control brains. This 
suggests that DRPLA protein undergoes greater complex formation in DRPLA brains 
and the expanded glutamine repeat may enhance complex formation of untruncated 
DRPLA protein in DRPLA brains. Immunohistochemical findings show that DRPLA 
protein is localized in the cytoplasm of the neuron, evidence that it undergoes 
rare disulfide bonding there.