Endophenotyping in idiopathic adult onset cervical dystonia

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. (Albanese et al., 2013) Idiopathic adult onset cervical dystonia (IAOCD) is considered to be an autosomal dominant genetic condition due to partially penetrant gene/s.(Stojanovic et al., 1995; Waddy et al., 1991) Hence most of the cases appear to be sporadic with a positive family history in 15-25%.(Waddy et al., 1991) Several genes have been mapped for families, which include members with cervical dystonia (Almasy et al., 1997; Charlesworth et al., 2012; Fuchs et al., 2009; Fuchs et al., 2013; Leube et al., 1996; Valente et al., 2001; Xiao et al., 2012) but in several other families with cervical dystonia linkage to these known genetic loci has been excluded.