Italian family with cranial cervical dystonia: Clinical and genetic study

A white Italian family affected by primary torsion dystonia (PTD) is descri bed. The family phenotype most commonly presented with adult onset, cranial cervical involvement, and focal or segmental distribution without progress ion to generalization. Thirty-nine family members and nine spouses were stu died. Five subjects received a diagnosis of definite PTD, three of probable PTD. Age at onset was in adulthood for all. In four definitely affected su bjects, dystonia started in the cranial or cervical districts: in one it pr esented as writer's cramp. Familial writer's cramp also occurred in the fam ily of the unrelated parent of the latter patient. The mean age at time of examination was 61.8 years in the individuals with a definite diagnosis; 60 in those with a probable diagnosis. At the time of examination, in most of the affected subjects, dystonia was focal; in three cases (two definitely and one probably affected), it was segmental. DNA linkage analysis, althoug h limited by the size of the family, suggested exclusion of linkage between the disease and known PTD loci (DYT6 and DYT7). The GAG deletion in the DY T1 gene was excluded in the proband and in the family member affected by wr iter's cramp.