Phenotypes and genetic architecture of focal primary torsion dystonia

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 83; no. 10; pp. 1006 - 1011
• Main Authors: Groen, Justus L, Kallen, Marlot C, van de Warrenburg, Bart P C, Speelman, J D, van Hilten, Jacobus J, Aramideh, Majid, Boon, Agnita J W, Klein, Christine, Koelman, Johannes H T M, Langeveld, Ton P, Baas, Frank, Tijssen, Marina A J
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.10.2012; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Age of Onset; Aged; Biological and medical sciences; Cohort Studies; Disease; Diseases of striated muscles. Neuromuscular diseases; Dystonic Disorders - genetics; Family medical history; Female; Genes; Genetic Predisposition to Disease; Genetic research; Genetic Testing; Genomes; Health risk assessment; Humans; Male; Medical sciences; Mendelian Randomization Analysis; Middle Aged; Mutation; Netherlands; Neurology; Patients; Phenotype; Prospective Studies; Research Design; Risk Factors; Studies; Netherlands; Striated muscle disease; Nervous system diseases; Phenotype; Central nervous system disease; Dystonia; Neurological disorder; Torsion; Involuntary movement; Cerebral disorder; Extrapyramidal syndrome
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp-2012-302729

BackgroundThe focal primary torsion dystonias (FPTDs) form a group of clinical heterogeneous syndromes and can be considered a genetic complex disease; it is thought to be primed by genetic variants with variable impact and triggered by non-genetic factors. Thorough clinical description of FPTDs cohorts is sparse but essential for further progress in genetic research.ObjectiveTo establish suggested relations between age at onset (AaO), site and family history in a large focal dystonias cohort and gain more insight into familial clustering for genetic research.Patients and methodsA prospective cohort study between March 2008 and March 2011, including 676 FPTD patients attending the botulinum toxin outpatient clinics of six Dutch movement disorder centres.Results and conclusionsOf all of the FPTD patients, 25% had a familial predisposition; in 2.4% a Mendelian inheritance pattern was noted. With a stronger family history, a significantly lower AaO was seen in all focal dystonias. In both the sporadic and familial focal dystonia groups, AaO had an effect on the distribution of dystonia, with a caudal to cranial tendency. In all focal dystonia forms, women were more frequently affected, except for writer's cramp. Careful clinical characterisation will allow the formation of phenotype subgroups. We suggest that genetic research into FPTDs will benefit from this approach and discuss genetic research strategies to decipher the complex background of focal dystonias.