Mutations in ANO3 cause dominant craniocervical dystonia: ion channel implicated in pathogenesis

In this study, we combined linkage analysis with whole-exome Sequencing of two individuals to identify candidate causal variants in a moderately-sized UK kindred exhibiting autosomal-dominant inheritance of craniocervical dystonia. Subsequent screening of these candidate causal variants in a large number of familial and sporadic cases of cervical dystonia led to the identification of a total of six putatively pathogenic mutations in ANO3, a gene encoding a predicted CA(2+)-gated Chloride Channel that we show to be highly expressed in the striatum. Functional studies using CA(2+) imaging in case and control fibroblasts demonstrated clear abnormalities in endoplasmic-reticulum-dependent CA(2+) signaling. We conclude that mutations in ANO3 are a cause of autosomal-dominant craniocervical dystonia. The locus DYT23 has been reserved as a synonym for this gene. The implication of an ion channel in the pathogenesis of dystonia provides insights into an alternative mechanism that opens fresh avenues for further research.