CHICAGO (Reuters) - A drug compound showed promise at reversing Huntington’s disease in mice without the toxic effects seen in similar compounds, raising hope for a treatment for this fatal, hereditary brain disorder, U.S. researchers said on Monday. The team at The Scripps Research Institute in La Jolla, California, studied HDACi 4b, a modified form of a group of compounds known as histone deacetylase or HDAC inhibitors that have shown promise at treating the disease in animals.