HUNTINGTONS-DISEASE GENE (IT-15) IS WIDELY EXPRESSED IN HUMAN AND RAT-TISSUES

Huntington's Disease (HD) is notable for selective neuronal vulnerabil ity in the basal ganglia and cerebral cortex. We have investigated in human and rodent tissues the expression of the gene (IT15) whose mutat ion causes HD. IT15 is widely expressed, with highest levels of expres sion in brain, but also in lung, testis, ovary, and other tissues. Wit hin the brain, expression is widespread with a neuronal pattern and is not enriched in the basal ganglia. Expression of IT15 is not reduced in the brain of HD patients when corrected for actin (though it is sli ghtly decreased in the striatum when uncorrected, consistent with neur onal loss). Thus, the widespread distribution of IT15 expression does not correspond with the restricted distribution of neuropathologic cha nges in HD. We suggest that pathophysiology may relate to abnormal cel l type-specific protein interactions of the HD protein.