Huntington's disease: Psychiatric practice in molecular genetic prediction and diagnosis

Abstract

BACKGROUND: Predictive genetic testing for Huntington's disease has been available in Cardiff since 1987 using linked genetic markers, and since 1993 using direct mutation testing, which can also be used as a diagnostic test. During this period there have been numerous referrals that have required liaison with psychiatric services at all stages of the testing programme. METHOD: A series of cases was selected to highlight issues from both genetic prediction and diagnosis that are relevant to psychiatric practice and have arisen during the testing programme. RESULTS: Issues have been raised concerning competence to consent to testing in the context of psychotic illness; depression and suicidal ideation in test candidates; requests for testing from third parties such as psychiatrists, social services and the courts; and testing of children. CONCLUSIONS: As genetic testing becomes possible for more disorders the lessons learned from Huntington's disease will provide valuable guidelines for counselling.