Mutation analysis of the sodium/hydrogen exchanger gene (NHE5) in familial paroxysmal kinesigenic dyskinesia.

Familial Paroxysmal Kinesigenic Dyskinesia (PKD) is an autosomal dominant condition characterized by attacks of dystonia or chorea triggered by sudden movements. Recently two separate loci for PKD, Episodic Kinesigenic Dyskinesia 1 (EKD1) and Episodic Kinesigenic Dyskinesia 2 (EKD2), have been mapped to chromosome 16 but the causative genes have not been identified. The Na(+)/H(+) exchanger gene (NHE5) involved in regulating intracellular pH lies in the EKD2 region. The coding region of the NHE5 gene in familial PKD was sequenced. We did not identify any mutations in the exons, intron/exon boundaries or the 5' and 3'UTR. This excludes mutations in the coding region of the NHE5 gene as a cause for familial PKD, but does not rule out a possible role of sequence variants in introns or regulatory regions.