Identification of a novel primary torsion dystonia loons (DYT13) on chromosome 1p36 in an Italian family with cranial-cervical or upper limb onset

Primary torsion dystonia (PTD) is a clinically and genetically heterogeneou s group of movement disorders, usually inherited in an autosomal dominant f ashion. Three PTD loci (DYT1, DYT6 and DYT7) have been identified to date. However, in several PTD families linkage to the known loci has been exclude d. We identified an Italian PTD family with 11 definitely affected members. Phenotype was characterised by juvenile or early-adult onset, prominent cr anial-cervical and upper limb involvement, mild course and occasional gener alisation. A genome-wide search performed in the family identified a novel PTD locus (DYT13) within a 22-cM interval on the short arm of chromosome 1, with a maximum lod score of 3.44 (theta = O) between the disease and marke r D1S2667.