No association between the tyrosine hydroxylase microsatellite marker HUMTH01 and schizophrenia or bipolar I disorder

Linkage and association studies have implicated the involvement of the tyrosine hydroxylase (TH) gene on chromosome 11p15 in schizophrenia and bipolar disorder (BPD). An association of BPD,vith a polymorphic tetranucleotide repeat, HUMTH01, located in the first intron of the human TH gene has been reported. Subsequently a rare allele, E-p ([TCAT](10)) of this microsatellite marker has been found in French and Tunisian schizophrenic patients only. We have genotyped a different sample of unrelated French schizophrenic and BPD patients from Alsace and matched controls for this polymorphic tetranucleotide repeat sequence. The E-p allele was insignificantly more common in controls than in schizophrenic patients, thus not showing a particular association with schizophrenia. In addition, analysis of the segregation of the E-p allele in the family of one of the schizophrenic patients showed no transmission of this allele from the healthy mother to her schizophrenic daughter. Nevertheless, we did observe a non-significant trend towards an association between HUMTH01 allele D ([TCAT](9)) and schizophrenia (Fisher's exact test, p = 0.053). No association was apparent between HUMTH01 and BPD Psychiatr Genet 8:45-48 (C) 1998 Lippincott-Raven Publishers.