Tourette syndrome (TS) is a neuropsychiatric disorder in which the pattern of symptom presentation can vary greatly between individuals. Although globally described, TS has not been well characterized in many parts of the world. Differences in individual and cultural perceptions of TS may impact its expression and recognition in some countries, confounding the identification of affected individuals. This study examines the phenomenology and presentation of TS in Costa Rica.
Clinical data on 85 Costa Rican subjects with TS (aged 5-29 years) initially recruited for a genetic study between 1996 and early 2000 were obtained by direct interview and review of medical records.
The clinical characteristics of TS were similar to that found elsewhere. The gender ratio was 4.6:1, the mean age of onset was 6.1 years, and 20% of subjects had coprolalia. However, the perceived impact of TS was different. Many subjects denied that their TS caused impairment or distress, even when objective evidence of impairment was available.
TS in Costa Rica is phenomenologically similar to TS seen in other parts of the world, but differs in perceived impairment. In other countries where cultural forces affect disease definition, close scrutiny of symptom expression and possible adjustment of phenotype definition may be important.
"In practical work, this population has also proved useful for genetic-mapping of some genes responsible for widely distributed monogenic diseases (Leon et al. 1981, Leon et al. 1992, Leon and Lalwani 2002, Lynch and Leon 2000, Uhrhammer et al. 1995, Lange et al. 1995, Telatar et al. 1998a, Telatar et al. 1998b, Udar et al. 1999, Leal et al. 2001, Berghoff et al. 2004). At the same time, his usefulness has generated large expectations for gene mapping of complex disorders (Escamilla et al. 1996, Freimer et al. 1996a, b, Frants 1999, DeLisi et al. 2001, Escamilla 2001, Mathews et al. 2001, Escamilla et al. 2002, Carvajal-Carmona et al. 2003, Segurado et al. 2003, Mathews et al. 2004, Pacheco and Raventós 2004). To date, important advances have been made in the mapping of various loci related to the bipolar disease (BPI) (Freimer et al. 1996b, McInnes et al. 1996, Escamilla et al. 1999, 2001, Garner et al. 2001, McInnes et al. 2001, Ophoff et al. 2002), although the first results do not seem to be promising regarding schizophrenia (DeLisi et al. 2002). "
[Show abstract][Hide abstract] ABSTRACT: In the last decade, the Costa Rican Central Valley population (CRCV), has received considerable scientific attention, attributed in part to a particularly interesting population structure. Two different and contradictory explanations have emerged: (1) An European-Amerindian-African admixed population, with some regional genetic heterocigosity and moderate degrees of consanguinity, similar to other Latin-American populations. (2) A genetic isolate, with a recent founder effect of European origin, genetically homogeneous, with a high intermarriage rate, and with a high degree of consanguinity. Extensive civil and religious documentation, since the settlement of the current population, allows wide genealogy and isonymy studies useful in the analysis of both hypotheses. This paper reviews temporal and spatial aspects of endogamy and consanguinity in the CRCV as a key to understand population history. The average inbreeding coefficients (a) between 1860 and 1969 show a general decrease within time. The consanguinity in the CRCV population is not homogeneous, and it is related to a variable geographic pattern. Results indicate that the endogamy frequencies are high but in general it was not correlated with a values. The general tendency shows a consanguinity decrease in time, and from rural to urban communities, repeating the tendencies observed in other countries with the same degree of development, and follows the general Western World tendency. Few human areas or communities in the world can be considered true genetic isolates. As shown, during last century, the CRCV population has had consanguinity values that definitively do not match those of true genetic isolates. A clear knowledge of the Costa Rican population genetic structure is needed to explain the origin of genetic diseases and its implications to the health system.
Revista de biologia tropical 10/2004; 52(3):629-44. DOI:10.15517/rbt.v1i2.15351 · 0.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The importance of genetics in understanding the etiology of mental illness has become increasingly clear in recent years, as more evidence has mounted that almost all neuropsychiatric disorders have a genetic component. It has also become clear, however, that these disorders are etiologically complex, and multiple genetic and environmental factors contribute to their makeup. So far, traditional linkage mapping studies have not definitively identified specific disease genes for neuropsychiatric disorders, although some potential candidates have been identified via these methods (e.g. the dysbindin gene in schizophrenia; Straub et al., 2002; Schwab et al., 2003). For this reason, alternative approaches are being attempted, including studies in genetically isolated populations. Because isolated populations have a high degree of genetic homogeneity, their use may simplify the process of identifying disease genes in disorders where multiple genes may play a role. Several areas of Latin America contain genetically isolated populations that are well suited for the study of neuropsychiatric disorders. Genetic studies of several major psychiatric illnesses, including bipolar disorder, major depression, schizophrenia, Tourette Syndrome, alcohol dependence, attention deficit hyperactivity disorder, and obsessive-compulsive disorder, are currently underway in these regions. In this paper we highlight the studies currently being conducted by our groups in the Central Valley of Costa Rica to illustrate the potential advantages of this population for genetic studies.
[Show abstract][Hide abstract] ABSTRACT: Substantial evidence suggests that both environmental and genetic factors contribute to the development and clinical expression of Tourette's syndrome. Although genetic studies of Tourette's syndrome are common, studies of environmental factors are relatively few and have not identified consistent risk factors across studies. This study examines in a large cohort of subjects (N=180) the relationship between prenatal/perinatal adverse events with Tourette's syndrome severity as determined by tic severity and rates of commonly comorbid disorders such as obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), and self-injurious behavior.
Tic severity, OCD, ADHD, self-injurious behavior, and exposure to a variety of prenatal/perinatal events were systematically assessed in all subjects enrolled in three genetic studies of Tourette's syndrome. Using linear and logistic regression, a best-fit model was determined for each outcome of interest.
Prenatal maternal smoking was strongly correlated with increased tic severity and with the presence of comorbid OCD in these Tourette's syndrome subjects. Other variables, such as paternal age and subject's birth weight, were significantly but less strongly associated with increased symptom severity. The authors found no association between symptom severity and hypoxia, forceps delivery, or hyperemesis during pregnancy, which have been previously identified as risk factors.
This study identifies prenatal maternal smoking as a strong risk factor for increased symptom severity in Tourette's syndrome.
American Journal of Psychiatry 07/2006; 163(6):1066-73. DOI:10.1176/appi.ajp.163.6.1066 · 12.30 Impact Factor
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