Mutations in GNAL cause primary torsion dystonia

Dystonia is a movement disorder characterized by repetitive twisting muscle contractions and postures(1,2). Its molecular pathophysiology is poorly understood, in part due to limited knowledge of the genetic basis of the disorder. Only three genes for primary torsion dystonia (PTD), TOR1A (DYT1)(3), THAP1 (DYT6)(4), and CIZ1(5) have been identified. Using exome sequencing in two PTD families we identified a novel causative gene, GNAL, with a nonsense p.S293X mutation resulting in premature stop codon in one family and a missense p.V137M mutation in the other. Screening of GNAL in 39 PTD families, revealed six additional novel mutations in this gene. Impaired function of several of the mutations was shown by bioluminescence resonance energy transfer (BRET) assays.