A 6 year old Omani Arab girl presented with one year's history of progressive intellectual deterioration, grimacing, dysarthria, dystonic posturing of the hands, and ataxia with falls, and was now severely retarded and mute. She came from a family affected by Huntington's disease (HD). Her parents, III. 19 and III.20, who were cousins aged 36 and 27 years respectively, reported that their mothers, II.2 and II.5, had died from HD. Both parents appeared to be healthy and were asymptomatic, but they suspected that their child had inherited the "family disease".