[Predictive testing: presymptomatic diagnosis in neurogenetic disorders]

Guidelines for presymptomatic testing for Huntington's disease: past, present and future in France

Huntington's disease was the first adult onset neurological disease for which presymptomatic genetic testing became possible. It served as a model for the approach which constituted a radical change in medical practice and provided an important framework for multi-step, multidisciplinary, counselling for at risk persons. We will review the historical context of guidelines and good clinical practices, the experiences of our team which covers more than 20 years of presymptomatic testing for Huntington's disease in France, and explore the impact of the new French legislation for the future of presymptomatic testing of diseases for which neither preventive measures nor curative treatments are yet available.

Psychological Impact of Predictive Genetic Testing in VCP Inclusion Body Myopathy, Paget Disease of Bone and Frontotemporal Dementia

Inclusion Body Myopathy associated with Paget's disease of bone and Fronto-temporal Dementia, also known as multisystem proteinopathy is an autosomal dominant, late onset neurodegenerative disorder caused by mutations in Valosin containing protein (VCP) gene. This study aimed to assess uptake and decision making for predictive genetic testing and the impact on psychological well-being. Individuals who had participated in the gene discovery study with a 50 % a priori risk of inheriting VCP disease were sent a letter of invitation offering genetic counseling and testing and were also invited to participate in this psychosocial study. A total of 102 individuals received an invitation and 33 individuals participated in genetic counseling and testing (32.3 %) with 29 completing baseline questionnaires. Twenty completed the follow-up post-test Hospital Anxiety and Depression Scale questionnaire including 13 of the 18 who had tested positive. Mean risk perception at baseline was 50.1 %. Reasons for testing included planning for the future, relieving uncertainty, informing children and satisfying curiosity. At baseline, one quarter of the participants had high levels of anxiety. However, scores were normal one year following testing. In this small cohort, one third of individuals at 50 % risk chose pre-symptomatic testing. Although one quarter of those choosing testing had high anxiety at baseline, this was not evident at follow-up.

[About Huntington's disease: role of families and health professionals in information transmission]

INTRODUCTION

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder. However, little information is available concerning the way each patient learns about the existence of Huntington's disease in his family and the way he transmits the information to his descendants. This study aims to specify the role of families and healthcare professionals in delivering information about the disease and its hereditary risk.

PATIENTS AND METHODS

Data from 105 consecutive patients were analyzed. The patients were categorized in four classes according to the way they received information about HD in their family: firstly, families where the disease was known; secondly, families where the HD was "poorly known"; thirdly, families where no antecedent could be found; fourthly, families where the disease was voluntarily hidden. The majority (52%) of the patients did not know the name of HD before being diagnosed. The patient choices for disclosure of hereditary risks to their relatives were influenced by the information they received about the disease in their own family. Patients from the second category (disease "poorly known") had the most difficulty in transmitting the information.

DISCUSSION

Despite the high risk of transmission, information about the disease is poorly known and transmitted in families concerned by HD. Although healthcare professionals confronted with the question of information delivery to relatives must always respect patient confidentiality, our results underline the need to more fully inform patients about the disease and transmission patterns. More help from healthcare professionals is needed to accompany HD patients concerning the question of transmitting information. The efficacy of a specific educational program should be assessed.