Gilles de la Tourette's syndrome: Tics and central nervous system stimulants in twins and nontwins
ABSTRACT Thirty-four of 170 surveyed individuals with Tourette's syndrome (TS) were treated with CNS stimulants before age 18. In 24% of treated individuals, persistent exacerbation of tics was closely associated with treatment. In 3%, tic response was transient, and in 24%, tics were not obviously associated with treatment. Six pairs of monozygotic twins were discordant for stimulant treatment, and all untreated co-twins also developed TS. The number of individuals in whom stimulants permanently exacerbate tics may be small, but the risk appears to be real. Genetic vulnerability and duration and timing of treatment may mediate response.
Full-textDOI: · Available from: R. Arlen Price, Aug 11, 2014
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ABSTRACT: To investigate the transmission of Tourette syndrome (TS) and associated disorders within families, complex segregation analysis was performed on family study data obtained from 53 independently ascertained children and adolescents with TS and their 154 first-degree relatives. The results suggest that the susceptibility for TS is conveyed by a major locus in combination with a multifactorial background. Other models of inheritance were definitively rejected, including strictly polygenic models, all single major locus models, and mixed models with dominant and recessive major loci. The frequency of the TS susceptibility allele was estimated to be .01. The major locus accounts for over half of the phenotypic variance for TS, whereas the multifactorial background accounts for approximately 40% of phenotypic variance. Penetrance estimates suggest that all individuals homozygous for the susceptibility allele at the major locus are affected, whereas only 2.2% of males and 0.3% of females heterozygous at the major locus are affected. Of individuals affected with TS, approximately 62% are heterozygous and approximately 38% are homozygous at the major locus. While none of the families had two parents affected with TS, 19% of families had two parents affected with the broader, phenotype, which includes TS, chronic tic disorder, or obsessive-compulsive disorder.The American Journal of Human Genetics 10/1996; 59(3):684-93. · 10.99 Impact Factor
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ABSTRACT: Tics are defined as involuntary and repetitive contractions of related groups of squelettal muscles. Their frequency can be exacerbated in certain situations or diminished in others. Chronic tics or the Gilles de la Tourette Syndrome (GTS) may be accompanied by concomitant disorders related to impulsivity. If one knows that the impulsivity variable can be found in a large majority of GTS cases, very few studies have attempted to document its frequency or intensity. Over the past decade, knowledge of the neuropsychology of GTS and the mechanisms underlying impulsivity has progressed rapidly. The current review of the literature, will describe the biological bases of this syndrome and problems of impulsivity in patients with GTS.
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