Candidate Locus for Chorea and Tic Disorders at 15q?

Cases of chromosomal aberrations are known to be associated with specific phenotypic abnormalities, including tics and chorea. We report the case of a 10-year-old caucasian boy with tics, chorea, and a de novo chromosome 15 paracentric inversion, 46,XY,inv(15) (q13;q22.3) identified with G-banding chromosome analysis (trypsin-Giemsa staining). Subsequent fluorescence in situ hybridization with locus-specific small nuclear ribonucleoprotein polypeptide N gene probe confirmed that the breakpoints of the inversion were distal to 15q12. Mutation analysis showed no mutation or polymorphism in the thyroid transcription factor 1 gene (TITF1). The results suggest that 15q is a region to explore for candidate genes of etiologic importance in the development of tics and chorea.