Complex segregation analysis of families ascertained through Gilles de la Tourette syndrome

Although family and twin studies suggest that genetic factors are involved in the etiology of Tourette syndrome and other related tic disorders, furth er evidence is needed to demonstrate that the familial transmission is cons istent with known genetic factors. We performed a complex segregation analy sis that allowed for a variable age of onset of Gilles de la Tourette, othe r tic disorders and obsessive compulsive phenotype information on 108 exten ded families, each ascertained through one Tourette proband by using regres sive models that are able to incorporate additional explanatory variables a nd major gene effects. A special version of the S.A.G.E. program, REGTLhunt , was used to explore the likelihood surface of all examined models. Result s indicated that the pattern of Tourette and other related tic disorders in our data sample is not consistent with Mendelian inheritance even after mo delling explanatory variables such as obsessive compulsive symptomatology. Genet. Epidemiol. 18:33-47, 2000. (C) 2000 Wiley-Liss, Inc.