THE GENETIC BASIS OF PRIMARY ADULT-ONSET DYSTONIA

Objectives. To identify novel genetic loci associated with primary adult-onset dystonia (AOD) and assess candidate genes from the literature. Secondary aimes. Epidemiological studies: to identify the rate of family history in people affeceted by AOD in Italy and to assess the impact of enviromental factors and clinical features between sporadic and familial cases. Background/rationale. Primary AOD has variable clinical expression as blepharospasm, oromandibular dystonia, cervical dystonia, laryngeal dystonia and arm dystonia. It usually starts after the age of twenty, has a peak age incidence between the 5th and the 7th decade, and predominates in women. Prevalence estimates vary widely across studies, but crude rates between 430 and 2250 cases per million are probably close to the true prevalence of the condition. AOD can be highly disabling and carry social and financial costs. Primary adult-onset dystonia is assumed to be partly genetic due to its aggregation within families and the identification of specific genetic loci including DYT 1, 2, 4, 6, 7, 13, 16, 17. Linkage to these loci is rare and accounts only for a small fraction of patients with adult-onset dystonia. Hence the gene(s) that lend risk to commonly occurring adult-onset primary dystonia are not known. Description of the project. The present project combines the clinical and genetic expertise of 9 leading Italian movement disorders centers. Data were collected from a wide, representative Italian sample of patients with AOD and their first degree relatives. Genetic factors will be studied by the affected sibling pair method (ASP) that allows identification of novel disease associated-loci, and also offers the potential to study candidate gene from the literature.