Predictive testing for Huntington's disease: ten years' experience in two Italian centres.

Pre-symptomatic testing for Huntington's disease (HD) has been available as a clinical service in the medical centres of Rome and Genoa since December 1987, initially by DNA-linkage and since mid-1993 by direct mutation analysis. A multidisciplinary approach and a protocol which follows the Ethical Issue Policy Statement on Huntington's Disease Molecular Genetics Predictive Test has been used. In the period under study, 332 subjects requested the test, 288 were enrolled in the protocol and nearly half of these completed it. One hundred and forty-eight people withdrew from the testing procedure for various reasons but most frequently due to a more realistic evaluation of all possible consequences of test results, induced by psychological counselling. Therefore, 140 people completed the test. The overall gene-carrier/non-carrier ratio was 0.46:1. None of the identified gene carriers had catastrophic reactions such as suicide, suicide attempts or major psychiatric disorders. All appear to have had a similar pattern of reactions to an adverse result and none expressed regret for undergoing the test. In conclusion, presymptomatic testing for HD can be considered a safe procedure without adverse consequences when framed in an integrated protocol at qualified genetic centres.