Idiopathic torsion dystonia linked to chromosome 8 in two mennonite families

Abstract
The DYT1 locus on chromosome 9q34 is responsible for most childhood limb‐onset idiopathic torsion dystonia (ITD). Linkage to DYT1 has been excluded in families with adult‐onset, and predominantly cranial–cervical, ITD. We mapped a locus (DYT6) associated with prominent cranial–cervical ITD in two large Mennonite families to chromosome 8. An identical haplotype spanning 40−cM segregates with ITD in these families, suggesting a shared mutation from the recent past.