Genetic study of an American family with DYT3 dystonia (lubag).

X-linked dystonia-parkinsonism (XDP, DYT3), endemic in the Philippine island of Panay, is characterized by the clinical onset with dystonia followed by parkinsonism. We found a 35-year-old American male patient, originally from Panay with typical XDP, has a 2-year history of parkinsonism, dystonia, and tremor. Ancestral DYT3 haplotype and disease-specific SVA (short interspersed nuclear element, variable number of tandem repeats, and Alu composite) retrotransposon insertion were identified in the DYT3 proband and two female unaffected family members. No mutation(s) and expression changes in peripheral blood lymphocytes were observed in the TATA-binding protein-associated factor 1 gene (TAF1) or the chemokine CXC motif receptor 3 gene (CXCR3) of the proband or other DYT3 carriers. These findings indicate blood DNA test has a diagnostic utility and implications for genetic counseling in families with DYT3. In contrast, TAF1 and CXCR3 gene expression in peripheral blood lymphocytes is not a suitable surrogate disease marker for DYT3.