SGCZ mutations are unlikely to be associated with myoclonus dystonia

• SGCE mutation rates in myoclonus dystonia vary, suggesting genetic heterogeneity.
• E- and ζ-sarcoglycan are both expressed in brain tissue.
• SGCZ was screened for mutations in SGCE-negative myoclonus dystonia cohort.
• No SGCZ mutations were identified in this cohort.
• SGCZ mutations are unlikely contribute to the genetic heterogeneity in myoclonus dystonia.

BackgroundMyoclonus dystonia syndrome (MDS) is a hyperkinetic movement disorder caused, in a proportion of cases, by mutations of the maternally imprinted epsilon-sarcoglycan gene (SGCE). SGCE mutation rates vary between cohorts, suggesting genetic heterogeneity. E- and ζ-sarcoglycan are both expressed in brain tissue. In this study we tested whether zeta-sarcoglycan gene (SGCZ) mutations also contribute to this disorder.MethodsPatients with clinically suspected MDS and no SGCE mutation were recruited and classified, according to previously published criteria, as to their likelihood of the movement disorder. All SGCZ exons and intron/exon boundaries were screened by direct sequencing.ResultsFifty-four SGCE mutation-negative patients were recruited from the UK and the Netherlands. Subdivided according to the likelihood of the movement disorder resulted in 17 ‘definite’, 16 ‘probable’ and 21 ‘possible’ cases. No pathogenic SGCZ mutations were identified.ConclusionsSGCZ mutations are unlikely to contribute to the genetic heterogeneity in MDS.