Mutations in DCC Cause Congenital Mirror Movements

Mirror movements (MM) are contralateralinvoluntary movements that mirror vol-untary ones. MM are occasionally found in young children, but persistence beyond age 10 is unusual except in certain disorders of nervous sys-tem crossing such as Klippel-Feil and Kallmann syndrome. The study of individuals with MM can provide important insights into the mechanisms of contralateral innervation. We recently described a large four-generation French Canadian (FC) family with isolated congen-italMM (CMM) (1). Pedigree analysis suggested autosomal dominant inheritance with incomplete penetrance. We conducted a genome-wide link-age analysis and identified a single significant locus on chromosome 18q21.2. Haplotype analysis indi-cated that all affected individuals share a com