Abnormal gene product identified in Huntington's disease lymphocytes and brain.

Huntington's disease(HD) is associated with expansion of an unstable CAG repeat. Using antibodies against the synthetic peptide corresponding to the sequence of HD gene IT15, we have identified the HD gene product in normal lymphocytes as a approximately 350kDa protein by immunoblot analysis. Moreover, when a modified SDS-PAGE using a low concentration of methylenbisacrylamide was run longer, abnormal immunoreactive bands larger than normal ones were found exclusively in HD samples. These results demonstrate the existence of the expanded CAG repeat gene product and open a possibility that the expanded polyglutamine stretch may really participate in the pathological process of the CAG repeat diseases.