Grant: Operating Grant

Predictive testing for Huntington disease (HD) has been available since 1986. This genetic test has the ability to predict whether an individual will develop HD in their lifetime and thus, have the ability to pass the disease onto their children. Some individuals who undergo predictive testing receive an unusual test result which differs from a positive or negative result. This result is called an intermediate allele(IA). Individuals with an IA will never develop HD but there remains a risk that their children or grandchildren could develop the disease. In the literature there remains many gaps in knowledge regarding IAs for HD. In particular, the current International Predictive Testing Guidelines do not address the possibility of this result, nor are the complexities surrounding this result acknowledged. This study will not only address these gaps, but will inform the development of clinical standards of care for communicating IA results during predictive testing. The specific objectives of this study are to determine the prevalence of IAs in a North American general population; determine quantified risk estimates for the likelihood than an individual with an IA will have a child who will develop the disease; and lastly, describe the psychological and social implications and impact of receiving an IA result. This study will represent the largest empirical study on HD IAs to date. Collectively, the three objectives of this unique, multidisciplinary study will provide the foundation on which to base the development of clinical standards and practice recommendations for IA predictive test results. These standards will help ensure that this subset of patients receive appropriate information, support, education, and counselling throughout their predictive testing process.