TOR1A and Onset: Two additional mutations have been described in Exon 5, the terminal exon of TOR1A. Leung and colleagues [21] reported a patient with early-onset dystonia and myoclonus who harbored an 18-bp deletion in Exon 5 which should eliminate 6 amino acids near the carboxy terminus of torsinA (Phe323_Tyr328del), including a putative phosphorylation site.