DYT7 gene locus for cervical dystonia on chromosome 18p is questionable.

Background: A locus implicated in autosomal dominant cervical dystonia was assigned to chromosome 18p in 1 large family more than 15 years ago. This locus was designated DYT7. We reanalyzed the family clinically and genetically.

Methods: Clinical reevaluation of all family members was performed. There was Sanger sequencing of candidate genes, SNP array analysis, and exome sequencing in definitely affected family members.

Results: Diagnosis of cervical dystonia was definite in 6 family members and possible in 12. Analysis of candidate genes in 18p revealed no alteration in definitely affected patients. There was no disease causing copy number variant in 18p. No potentially disease-causing mutations were detected in 18p by exome sequencing. The CIZ1 gene, mutated in some cases of cervical dystonia, was excluded.

Conclusions: Location of DYT7 on 18p in autosomal dominant cervical dystonia is questionable. We demonstrate genetic heterogeneity of this form of dystonia.