Hum Genet. 2003 Jul;113(2):154-61.
Epub 2003 Apr 16.
Translocation breakpoint
in two unrelated Tourette syndrome cases, within a
region previously linked to the disorder.
Crawford FC, Ait-Ghezala G,
Morris M, Sutcliffe MJ, Hauser RA, Silver AA, Mullan MJ.
Department of Psychiatry, University of South Florida, 3515 E. Fletcher Avenue,
Tampa, FL 33613, USA. fcrawfor@hsc.usf.edu
Tourette syndrome (TS) is a complex neuropsychiatric
disorder characterized by both motor and vocal tics. The etiology of TS is
poorly understood; however, evidence of genetic transmission arises from family
and twin studies. A complex mode of inheritance has been suggested, likely
involving contributions of several genes with different effect size. We
describe here two unrelated families wherein balanced t(6;8)
chromosomal translocations occur in individuals diagnosed with TS. In one of
these families, the transmission of the translocation is associated with
learning and behavioral difficulties; in the other family, one parent is
unaffected and the other cannot be traced, thus transmission cannot be
demonstrated and it is possible that the translocation may have occurred de novo.
The breakpoint on chromosome 8 occurs within the q13 band in both families,
suggesting that a gene or genes in this region might contribute to the TS
phenotype. Existing linkage and cytogenetic data,
suggesting involvement of chromosome 8 in TS families and individuals, further
support this hypothesis. We have identified two YAC clones mapping distal and
proximal to the chromosome 8 translocation site, as
determined by fluorescent in situ hybridization (FISH).
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Keywords: Tourette Syndrome, translocation breakpoint, Human Genetics