The common Arg788Leu was identified in two unrelated patients with neurological disease. The
2299insC mutation was identified in monozygotic twins both of whom had combined neurological and hepatic diseases, Parkinsonism, and cirrhosis. The younger brother, who developed symptoms three months before treatment started, had a better outcome. The older brother had onset two years earlier than his brother. He became bedridden from Parkinsonism although his liver function tests were back to normal