Ce travail de recherche vise à évaluer les enjeux éthiques posés par le recours au diagnostic anténatal dans le cadre des maladies génétiques à révélation tardive.Notre première étude a été d’analyser les décisions prises en réunions de Centres Pluridisciplinaires de Diagnostic Prénatal (CPDPN) et, à travers des situations réelles et singulières, relever les éléments de discussion et plus particulièrement ceux pouvant influencer la décision. Nous avons, ensuite réalisé deux enquêtes par questionnaires qui ont permis: 1) D’explorer le point de vue des personnes directement concernées par une telle pathologie (porteurs du gène responsable - malades ou asymptomatiques -, conjoints et/ou parents d’une personne porteuse du gène) ; 2) D’étudier la position des professionnels de la parentalité, travaillant en lien avec un CPDPN, et qui sont décideurs de la recevabilité ou non d’une demande de diagnostic anténatal dans ce contexte.Ce travail a ainsi contribué à faire émerger des questionnements pertinents sur le plan éthique et une réflexion sur de possibles évolutions législatives et sociétales dans ce domaine. / This research carries out with the aim of evaluating the ethical challenges faced by the use of antenatal diagnosis in late-onset genetic diseases.In a first study, we analysed the decisions of Multidisciplinary Centres for Prenatal Diagnosis (MCPD) and, through real and specific situations, we identified the elements for discussion and more particularly the ones that could influence the decision-making process. Then, we conducted two questionnaire surveys that allowed to: 1) Explore the viewpoints of people directly affected by this type of pathology (responsible gene carriers - ill or asymptomatic individuals -, partners and/or parents of gene carriers); 2) Examinate the opinions of professionals, working in association with a CPDPN and who are decision-makers of the acceptability or not for an antenatal diagnosis request in this context.This work has therefore brought out questions on ethics, and views on the potential legal and social developments in this area.

The aims were to investigate the accuracy of ultrasound in diagnosis of structural fetal anomalies with special focus on false positive findings (I), to evaluate the additional value of second trimester fetal MRI on pregnancy management (II-III) and to estimate the ascertainment in the Swedish Birth Defects Registry and incidence of spina bifida and cleft lip/palate (IV). Retrospectively, 328 fetal autopsies were identified where pregnancies were terminated due to ultrasonographically diagnosed fetal anomalies. In 175 (53.4 %) cases ultrasound and fetal autopsy were identical, in 124 (37.8 %) ultrasound was almost correct, in 23 (7.0 %)  ultrasound diagnoses could not be verified, but fetal autopsy showed other anomalies with at least the same prognostic value and in six (1.8 %)  ultrasound diagnosis could not be verified and autopsy showed no or less severe anomalies (I). Prospectively, 29 pregnancies with CNS- (II) and 63 with non-CNS-anomalies (III) were included. In the CNS study MRI provided no additional information in 18 fetuses (62 %), additional information without changing the management in 8 (28 %) and additional information altering the pregnancy management in 3 (10%). In the non-CNS study the corresponding figures were 43 (68 %), 17 (27 %) and three (5 %), respectively. MRI in the second trimester might be a clinically valuable adjunct to ultrasound for the evaluation of CNS anomalies, especially when the ultrasound is inconclusive due to maternal obesity (II) and in non-CNS anomalies in cases of diaphragmatic hernia or oligohydramnios (III). In newborns, the ascertainments of birth defects are relatively high and assessable, but in pregnancy terminations they are lower or unknown. The incidence of newborns with spina bifida has decreased because of an increased rate of pregnancy terminations (>60%). There is room for improvement concerning the reporting of anomalies from terminated pregnancies (IV).