The gene for Huntington's disease

Tourette's syndrome in the year 2000

OBJECTIVE

To examine the current status of knowledge of Tourette's syndrome (TS) and to highlight those areas of research that are most likely to have the most significant advances in the next few years into the 21st century.

METHOD

Index Medicus was consulted from its beginning in 1885 until 1964 (inclusive), looking initially under the title 'tics' and subsequently under 'Tourette's Disorder'. From 1965 and the advent of MEDLINE, a search was performed looking for 'Tourette's'. A chronological examination of TS in the medical literature is presented. Some issues surrounding Huntington's Disease (HD) research are pertinent to TS and may serve as a guide in the future direction of TS research; these issues have been identified and illustrated in the context of TS. Where relevant, other medical disorders are also commented on.

RESULTS

There has been a steady increase in the volume of TS literature since 1885, with a marked increase since 1980, changing in focus from a psychological to a neurobiological viewpoint. Current areas of interest include genetics, comorbid psychopathologies, neuroimaging, treatments, epidemiology and educational considerations. Issues raised by HD and other movement disorders such as Parkinson's Disease (PD) are predictive testing, gene therapy and neural transplants.

CONCLUSIONS

The year 2000 is likely to herald a significant increase in our knowledge of the genetics and neuroimaging of TS, with new developments in therapy. A broadening of awareness of TS among health workers and teachers in particular is likely to increase the number of diagnosed patients and, hence, new challenges will be posed to existing resources for health and educational provision.

Genetic mechanisms and mental retardation

The past five years have witnessed rapid and apparently relentless progress in the delineation of the genetic basis of disorders associated with mental retardation. Each gene discovery has a new story to tell but inevitably generates further questions. For the clinical geneticist and, perhaps more importantly, for patients and their families, many of these recent discoveries have yielded information which has immediate implications for diagnostic testing, family and population screening and prenatal testing. Many of the ethical issues consequent upon the rapid progress are only now being addressed. This article highlights a number of disorders whose molecular genetic basis has recently been further characterised. Brain development and maintenance of neurological networks provide the unifying theme; the genetic defects are disparate and each of their mechanisms appears to be novel.

Ethical and social issues in presymptomatic testing for Huntington's disease: a European Community collaborative study. European Community Huntington's Disease Collaborative Study Group

An analysis of social and ethical aspects of presymptomatic testing for Huntington's disease has been carried out, based on data on linked DNA markers, from four major testing centres in different European Community countries (Belgium, Italy, Netherlands, and United Kingdom). Information was available on 603 applicants, with 213 final results given, of which 32% gave an increased risk. A series of specific issues and problems were documented systematically for all applicants, results being given on frequency of occurrence and illustrated by individual case histories. The principal issues could be grouped as problems of inappropriate referral, problems involving relatives, and problems relating to disclosure of results. At least one important problem was encountered in 46% of applicants, emphasising the importance of expert counselling, preparation, and support of applicants, and of close liaison between clinical, counselling, and laboratory staff. The extensive and detailed information available for Huntington's disease from this and other studies will be of considerable value in relation to genetic testing for other late onset genetic disorders and will be even more relevant to Huntington's disease now that specific mutation analysis is possible for this disorder.