Genetics in movement disorders

: Genetic considerations in movement disorders are described. 1) Familial parkinsonisms are heterogeneous; genes for two of them, 'Lubag' and Waisman syndrome have been mapped to X chromosome, though genes for others do not have been mapped. 2) The responsible gene for Huntington's disease has been cloned recently and named huntingtin. A (CAG)n repeat longer than the normal range was observed in huntingtin gene. The (CAG)n repeat appears to be located within the coding sequence of a predicted approximately 348 kD protein that is widely expressed but unrelated to any known gene. The expansion of an unstable trinucleotide CAG repeat are also the causes of hereditary neurodegenerative diseases such as X-linked bular and spinal muscular atrophy and spinocerebellar ataxia type 1. 3) There are various forms in hereditary dystonia. Although the responsible gene for idiopathic torsion dystonia, inherited as an autosomal dominant pattern, has been mapped to 9q 32-34, genes for others do not have been mapped. 4) The Gilles des la Tourette syndrome (GTS) is a hereditary, neuropsychiatric-neurobehavioral disorder with childhood onset that is characterized by motor and vocal tics. About 80% of the human genome could be excluded as possible site for the GTS gene by studies with over 600 DNA markers in an international collaborative effort, but actual localization has not yet been accomplished.