Role of the dopamine D5 receptor (DRD5) as a susceptibility gene for cervical dystonia. (Short Report).

Cervical dystonia (CD) is one of the most common forms of primary dystonia. The pathogenesis of the disease is still unknown, although evidence suggests a role for genetic factors. Recently, a polymorphism in the dopamine D5 receptor (DRD5) gene has been associated with the disease in a British population, suggesting that DRD5 is a susceptibility gene for CD. To confirm these data, we performed a case-control study of the microsatellite (CT/GT/GA)(n) at the DRD5 locus in 104 Italian CD patients and 104 healthy controls. The frequency of allele 4 was higher in the CD patients compared to the controls. This resulted in a twofold increased risk of developing the disease. These results provide further evidence of an association between DRD5 and cervical dystonia, supporting the involvement of the dopamine pathway in the pathogenesis of CD.

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Cervical dystonia (CD), one of the most common forms of primary torsion dystonia (PTD), is characterised by sustained muscle contractions of the cervical musculature, leading to twisting and repetitive movements and abnormal postures of the neck. (1) Genetic studies have contributed to an understanding of the basis of the disease. Although the great majority of cases are considered sporadic, it has been shown that CD is more common in first degree relatives of affected individuals than in the general population, and concordance in monozygotic twins has been reported. (2 3) A genome-wide search in a large German kindred with adult onset CD led to the identification of a locus on chromosome 18p (DYT7). (4) However, linkage to DYT7 was not confirmed in other PTD families and the gene has not yet been cloned. A recent study on a cohort of English patients affected by CD showed an association between the dopamine D5 receptor (DRD5) and …