Movement disorders: Advancing our understanding of dystonias-genetic studies reveal TUBB4 mutation in patients with dystonia type 4.

Dystonia type 4 (DYT4), or 'whispering dysphonia', is one of the few genetically linked dystonic disorders for which no locus or gene had been identified. Now, two studies published in Annals of Neurology have used extensive genetic and linkage analysis in a large family affected by DYT4 to reveal the causative mutation as a single amino acid variation in the tubulin β-4 (TUBB4) gene.