Abstract

Myoclonus–dystonia syndrome (MDS) is a rare movement disorder characterised by myoclonus mainly of the trunk and upper limbs in conjunction with dystonic posturing, usually of neck and hands. Mutations of the maternally imprinted epsilon-sarcoglycan (SGCE) gene cause autosomal dominant MDS in 30% of cases. Epsilon-sarcoglycan forms part of the dystrophin-associated glycoprotein complex (DAG) situated in the cell membrane, its neural function remains uncertain. Psychiatric disorders have frequently been described in MDS, suggesting that epsilon-sarcoglycan may have a role in psychiatric disease. We have conducted a systematic review of previous publications detailing SGCE mutation status and psychiatric disease. Inclusion criteria included: use of recognised MDS diagnostic criteria, a case control study design, SGCE status, and the use of standardised and validated psychiatric assessment tools. When data were pooled, these showed a significant association between SGCE mutations and psychiatric disease (p=0.028), including obsessive-compulsive disorders, depression and generalised anxiety disorder. This association was further strengthened when inclusion criteria were relaxed to include details of psychiatric diagnoses obtained by clinical history or patient self-report (p=0.012). This supports the view that psychiatric disorders form part of the MDS phenotype and that epsilon-sarcoglycan may have an important role to play.