Les maladies rares sont définies en Europe par une prévalence inférieure à 1/2 000 cas et représentent plus de 7000 entités différentes dont 80% sont d’origine génétique. La majorité est de début pédiatrique. J’ai réalisé l’étude de cas familiaux rares avec récurrence dans la fratrie de cardiopathies congénitales avec hétérotaxie (défaut de latéralité gauche/droite) d’une part, et de mort subite cardiaque inexpliquée chez le nourrisson ou en période néonatale d’autre part. La stratégie d’identification de gène par séquençage de l’exome au sein de ces familles dans l’hypothèse d’une transmission autosomique récessive a permis d’identifier trois gènes et d’en étudier deux sur le plan fonctionnel dans différents modèles : 1) Perte de fonction de MMP21 et malformations cardiaques congénitales par anomalie de latéralité embryonnaire. MMP21 code pour une métallopeptidase matricielle dont nous démontrons le rôle très spécifique au niveau du nœud embryonnaire sur un modèle poisson zèbre et souris. Ceci ouvre de nouvelles perspectives dans la compréhension des mécanismes moléculaires qui sous-tendent la mise en place de l’asymétrie gauche/droite chez la plupart des vertébrés. De manière intéressante, alors que tous les mammifères ont le cœur latéralisé à gauche, tous n’ont pas un gène MMP21 codant. Il existe donc plusieurs voies de signalisation de l’asymétrie gauche/droite chez les vertébrés. 2) Mutations hypomorphes de PPA2 et mort subite cardiaque chez le nourrisson. PPA2 code pour une pyrophosphatase mitochondriale et les données chez la levure ont montré que la fonction de cette enzyme était essentielle au fonctionnement mitochondrial. Nous décrivons une nouvelle présentation clinique de maladie mitochondriale responsable de décès par arrêt cardiaque inattendu chez le nourrisson. 3) Perte de fonction de PLCD3 et cardiomyopathie foudroyante par apoptose et nécrose diffuse des cardiomyocytes en période néonatale. Ce résultat nécessite encore d’être confirmé par l’identification d’autres cas mais la fonction de la protéine et des données chez la souris sont des arguments majeurs en faveur de la causalité du gène. Au total, ces travaux sont déterminants à la fois sur le plan clinique dans le cadre du conseil génétique pour les familles concernées et sur le plan fondamental en éclairant les mécanismes biologiques de mise en place de l’axe gauche-droit au cours du développement embryonnaire avec MMP21, sur le rôle essentiel de PPA2 dans la mitochondrie et sur celui de PLCD3 dans la survie des cardiomyocytes en postnatal. / Rare diseases are defined in Europe by a prevalence of less than 1/2,000 individuals and represent more than 7,000 different diseases of which 80% are genetic. Most have a paediatric onset. My project involved the study of rare cardiac disorders in familial cases with recurrence in siblings, focusing on congenital heart disease in the context of heterotaxia (laterality defects) and sudden unexpected death due to cardiac arrest in infancy and the neonatal period. Whole exome sequencing was used as a tool for disease gene discovery in these families with the hypothesis of autosomal recessive inheritance. This strategy led to the identification of 3 novel disease genes. I performed functional validation for two of these genes in different models, confirming their involvement in each disease. 1) Loss of function of MMP21 and cardiac malformations due to left-right patterning defects during embryonic development. MMP21 encodes a metallopeptidase for which I demonstrated a highly specialized role in the generation of left-right asymmetry at the node using zebrafish. This gives new insight into the molecular mechanisms at the origin of left-right asymmetry in vertebrates. Interestingly, all mammals have a left-sided heart, but some species have lost the Mmp21 gene, indicating that there are different pathways leading to left-right determination in vertebrates. 2) Hypomorphic mutations in PPA2 cause sudden cardiac arrest in infants. PPA2 is a nuclear gene encoding the mitochondrial pyrophosphatase and using a yeast model we showed that this enzyme is essential for the mitochondrial energy transducing system and biogenesis. I described a novel clinical spectrum for a mitochondrial disease responsible for unexpected cardiac arrest in infancy. 3) PLCD3 loss of function and fatal cardiomyopathy by cardiomyocyte apoptosis and necrosis in neonates. Exome sequencing in one familial case with 2 siblings presenting fatal cardiomyopathy led to the identification of compound heterozygous mutations in PLCD3, a gene previously implicated in a similar pathology in a mouse model. Identification of further cases with mutations in this gene will be needed in order to confirm the role of PLCD3 in the disease. In total, these studies are crucial from a clinical point of view for the genetic counseling of the affected families and they contribute to the elucidation of biological mechanisms of embryonic development and left-right determination (MMP21), mitochondrial function (PPA2) and post-natal cardiomyocyte survival (PLCD3).

Na última década, a podridão vermelha das raízes da soja (PVR), ou síndrome da morte súbita, causada pelo fungo Fusarium solani f.sp. glycines, tornou-se uma doença que é motivo de preocupação para os sojicultores, técnicos e pesquisadores nas regiões onde esta doença já foi constatada, sendo a única estratégia de controle viável a utilização de cultivares resistentes. Diante disto, o principal objetivo do presente trabalho foi o estudo do controle genético da reação da soja a PVR por meio de técnicas de genética clássica e molecular. Foi utilizada a geração F2 de um dialelo 5x5, sem os recíprocos, envolvendo cinco cultivares: Forrest, MG/BR-46 (Conquista), IAC-4, FT-Cristalina e FT-Estrela, sendo as duas primeiras mais resistentes a PVR que IAC-4, considerada moderadamente resistente e, as duas últimas, altamente suscetíveis. Além de testes de inoculação com as cultivares, foram conduzidos três experimentos com a geração F2: um em telado (semeadura em julho de 2001) e dois em casa de vegetação (semeadura em setembro de 2001 e julho de 2002), sendo os dois primeiros em blocos ao acaso e o terceiro no delineamento inteiramente casualizado. O patógeno foi inoculado com grãos de sorgo colonizados, colocando-se três grãos no fundo de cada cova, no momento da semeadura, fazendo-se cinco covas por vaso, cada qual constituindo uma parcela com cinco plantas. Em cada experimento, foram avaliadas individualmente 50 plantas de cada genitor e 150 plantas de cada cruzamento F2, entre os 30 e 40 dias após a emergência, utilizando-se uma escala de notas de 1 a 5 para a severidade dos sintomas foliares da PVR. A porcentagem de incidência da doença em cada parcela e um índice de doença também foram calculados. Nas análises de variância com os dados de médias de parcelas, observaram-se diferenças altamente significativas entre os genitores e entre populações F2 para a severidade e índice de doença dos sintomas foliares, na maioria dos casos, embora os genitores resistentes e suscetíveis não foram muito contrastantes. As cultivares Forrest e Conquista comportaram-se sempre como resistentes, e Cristalina e Estrela como suscetíveis, enquanto que IAC-4 apresentou comportamento instável. Pela análise dialélica de Jinks-Hayman reafirmou-se a influência do ambiente sobre o controle da resistência à manifestação dos sintomas foliares da PVR, a qual foi controlada quantitativamente. Nos experimentos de 2001, constatou-se apenas a ação de efeitos gênicos aditivos. Porém, no experimento conduzido em telado, a resistência demonstrou controle por genes recessivos, enquanto que na casa de vegetação, na maior parte, por genes dominantes. No experimento de 2002 constatou-se a presença de efeitos gênicos aditivos e de dominância, predominando o efeito destes últimos. Assim, com base no experimento de 2002, para o grupo de cultivares estudado, os parâmetros genéticos calculados permitiram verificar que: o grau médio de dominância indicou a presença de sobredominância; predominaram genes recessivos no grupo dos genitores; pelo menos três locos ou blocos gênicos que exibiram dominância foram responsáveis pelo controle da resistência a PVR; as herdabilidades estimadas no sentido restrito foram médias (0,33 a 0,62) e, no sentido amplo, altas (0,90 a 0,96), confirmando a presença de dominância; a resistência foi controlada, na maior parte, por genes dominantes e a ordem decrescente de dominância das cultivares foi a seguinte: 'Conquista', 'Cristalina', 'Forrest', 'Estrela' e 'IAC-4'; a exclusão de 'Cristalina', por suspeita de apresentar distribuição de genes correlacionada com 'Conquista' e 'Estrela', melhorou a adequação dos dados de índice de doença ao modelo genético aditivo-dominante de Jinks-Hayman. A utilização de cinco marcadores moleculares microssatélites (Satt163, Satt309, Satt354, Satt371 e Satt570), relatados como ligados a cinco QRLs da PVR, indicou a provável presença de multialelismo nestes locos, o que não invalidou a adequação dos dados ao modelo de Jinks-Hayman. Pela análise de ligação entre 126 indivíduos F2 do cruzamento 'Conquista' x 'Estrela' com os marcadores Satt163 e Satt354, no experimento conduzido em telado, houve ligação fraca (P<0,10) entre estes locos e os respectivos QRLs, havendo tendência dos alelos recessivos serem os responsáveis pelo controle da resistência nestes dois locos, concordando com os resultados da análise dialélica para este experimento. / In order to study the genetic control of soybean resistance to sudden death syndrome (SDS) by classical and molecular genetic techniques a 5x5 diallel with the F2 generation, without the reciprocals, was carried out. The following parents were used: 'Forrest', 'MG/BR-46 (Conquista)', 'IAC-4', 'FT-Cristalina' and 'FT-Estrela'. The first two cultivars are more resistant to SDS than 'IAC-4', that is considered to be moderately resistant to SDS, and the last two cultivars are highly susceptible. Tests of inoculation were done with the cultivars and three experiments with the F2 generation (two in 2001 and one in 2002) were carried out, all of them in greenhouses. The fungus was inoculated by three colonized sorghum grains placed at the bottom of the holes at the planting. It was used five-holes/clay pot, which one was considered a plot with five plants. In each experiment with the F2 generation 50 single plants of each parent and 150 single plants of each F2 population were evaluated between 30 and 40 days after emergency by using a scale (1 to 5) based on foliar severity symptoms. The disease incidence and a disease index also were calculated for each plot. In the ANOVAs with data plot average for severity and disease index highly significant differences were detected among the treatments in almost all cases, although the resistant and the susceptible parents did not differ too much. The parents 'Forrest' and 'Conquista' were always more resistant than the others. 'Cristalina' and 'Estrela' were the most susceptible parents, while 'IAC-4' was unstable. Jinks-Hayman's analysis reaffirmed the environment effect on the genetic control of the resistance to SDS foliar symptoms, which was quantitatively controlled. In the 2001 experiments there was observed only additive genic effects, but in one experiment recessive genes had controlled the resistance, while in the other, in major part, dominant genes had controlled the resistance to SDS. In the 2002 experiment it was showed mainly dominance effects and also some additive genic effects. In the last experiment, for the group of parents used, the genetic parameters indicated that: the average degree of dominance showed the presence of overdominance; there were more recessive than dominants genes in the group of the parents; at least three loci or genic blocks that exhibited dominance were responsible for the genetic control of the resistance to SDS; the heritability in the narrow-sense had middle values (0.33 to 0.62), and in the broad-sense had high values (0.90 to 0.96), reinforcing the presence of dominance effects; the resistance to SDS was controlled, mostly, by dominant genes; the decreasing order of dominance of the parents were: 'Conquista', 'Cristalina', 'Forrest', 'Estrela' and 'IAC-4'; and the exclusion of 'Cristalina' of the diallel for disease index by suspect of gene correlated distribution with 'Conquista' and 'Estrela' improved the fitting of the data to Jinks-Hayman's additive-dominant model. Five microsatellite markers (Satt163, Satt309, Satt354, Satt371 and Satt570), reported as linked to five SDS QRLs, were used and showed the possibility of occurrence of multiallelism in those loci, but this evidence did not invalidate the fitting of the data to Jinks-Hayman's model. The molecular analysis in 126 plants of 'Conquista' x 'Estrela' cross with the markers Satt163 and Satt354, in the first experiment of 2001, showed the tendency of weakly association (P<0,10), between those loci and the QRLs. This analysis showed also tendency that the recessive genes controlled the resistance to SDS in both loci, in according to the results obtained in the diallel analysis for this experiment.

<p>När döden inträffar plötsligt, har efterlevande inte fått någon chans till mental förberedelse inför dödsfallet. Efterlevande löper därmed stor risk att drabbas av komplicerade sorgereaktioner, med psykisk och fysisk ohälsa som följd. Denna grupp möts inte i tillräckligt stor utsträckning av strukturerad evidensbaserad omvårdnad, i proportion till efterlevande vid väntade dödsfall. Syftet med litteraturstudien var att belysa närståendes behov vid plötslig död samt att understryka relevanta omvårdnadsåtgärder i akuta skeden. Litteraturstudien är baserad på 13 vetenskapliga artiklar som på olika sätt behandlar närståendes behov vid plötslig död. Resultatet behandlar närståendes behov utifrån fem kategorier: bemötande, information, närvaro, avsked och uppföljning. Närstående upplever ofta brister i sjukvårdspersonalens förmåga att möta deras behov. Brister som rapporterats gäller framförallt närståendes behov av bemötande och information, vilket kan sätta djupa spår hos efterlevande. Kunskapen om nyttan av att möta efterlevandes behov av uppföljning efter plötsliga dödsfall bedöms i dagsläget inte vara tillräcklig. Kunskapen om närståendes behov vid plötsliga dödsfall behöver fördjupas. Ytterligare forskning krävs, då området i dagsläget är eftersatt. Initialt bör dock existerande forskning implementeras.</p> / <p>When sudden death occurs, the survivors do not have a chance to mentally prepare for the loss. Survivors suffer high risk of complicated grief reactions, resulting in mental and physical illness. This group is not met sufficiently by structured evidence-based care, in proportion to the care of survivors expecting the loss. The purpose of the literature study was to highlight the needs of relatives confronted with sudden death, and to emphasize relevant nursing measures in acute stages. This paper is a survey of literature based on 13 research articles, in various ways dealing with needs of bereaved confronted with sudden death. The result deals with the needs of close relatives based on five categories: caring, information, proximity, viewing the body and follow-up. Survivors often experience gaps in health professionals' ability to meet their needs. Deficiencies regarding relatives’ needs of caring and information often results in negative long lasting memories. Knowledge of the benefits of meeting the needs of survivors regarding follow-up after a sudden death, is to this date considered insufficient. Knowledge of survivors confronted with sudden death need to be further explored. Further research is required, since the area of current situation is neglected. Initially, however, existing research need to be implemented.</p>

När döden inträffar plötsligt, har efterlevande inte fått någon chans till mental förberedelse inför dödsfallet. Efterlevande löper därmed stor risk att drabbas av komplicerade sorgereaktioner, med psykisk och fysisk ohälsa som följd. Denna grupp möts inte i tillräckligt stor utsträckning av strukturerad evidensbaserad omvårdnad, i proportion till efterlevande vid väntade dödsfall. Syftet med litteraturstudien var att belysa närståendes behov vid plötslig död samt att understryka relevanta omvårdnadsåtgärder i akuta skeden. Litteraturstudien är baserad på 13 vetenskapliga artiklar som på olika sätt behandlar närståendes behov vid plötslig död. Resultatet behandlar närståendes behov utifrån fem kategorier: bemötande, information, närvaro, avsked och uppföljning. Närstående upplever ofta brister i sjukvårdspersonalens förmåga att möta deras behov. Brister som rapporterats gäller framförallt närståendes behov av bemötande och information, vilket kan sätta djupa spår hos efterlevande. Kunskapen om nyttan av att möta efterlevandes behov av uppföljning efter plötsliga dödsfall bedöms i dagsläget inte vara tillräcklig. Kunskapen om närståendes behov vid plötsliga dödsfall behöver fördjupas. Ytterligare forskning krävs, då området i dagsläget är eftersatt. Initialt bör dock existerande forskning implementeras. / When sudden death occurs, the survivors do not have a chance to mentally prepare for the loss. Survivors suffer high risk of complicated grief reactions, resulting in mental and physical illness. This group is not met sufficiently by structured evidence-based care, in proportion to the care of survivors expecting the loss. The purpose of the literature study was to highlight the needs of relatives confronted with sudden death, and to emphasize relevant nursing measures in acute stages. This paper is a survey of literature based on 13 research articles, in various ways dealing with needs of bereaved confronted with sudden death. The result deals with the needs of close relatives based on five categories: caring, information, proximity, viewing the body and follow-up. Survivors often experience gaps in health professionals' ability to meet their needs. Deficiencies regarding relatives’ needs of caring and information often results in negative long lasting memories. Knowledge of the benefits of meeting the needs of survivors regarding follow-up after a sudden death, is to this date considered insufficient. Knowledge of survivors confronted with sudden death need to be further explored. Further research is required, since the area of current situation is neglected. Initially, however, existing research need to be implemented.

科学研究費補助金 研究種目:一般研究(B) 課題番号:06454236 研究代表者:豊嶋 英明 研究期間:1994-1995年度

Thesis (MMed (Pathology. Forensic Medicine))--University of Stellenbosch, 2010. / Bibliography / ENGLISH ABSTRACT: Background - The workload of the forensic pathologist and Forensic Pathology Services staff is increased by the referral of potentially unnecessary natural cases to the Forensic Pathology Services. The primary aims of the medico-legal autopsy are limited to establishing a cause of death in presumed unnatural cases, and to exclude criminality or negligence. Objective – To determine the final outcomes of forensic post-mortem examinations in “sudden and unexpected” adult deaths over a 5 year period. Methods - An observational, retrospective, descriptive study was conducted. ”Sudden and unexpected” adult deaths referred to Tygerberg Forensic Pathology Services between 1 January 2001 and 31 December 2005 were reviewed. Data was collected from the autopsy reports, contemporaneous notes and hospital records. Findings – A total of 816 adult cases of sudden and unexpected death were referred to Tygerberg Forensic Pathology Services over the 5 year period studied. Complete autopsies had been performed in 74% (601/816) of cases. The presumed manner of death was natural in 79 % of cases, and an increase in the number of natural cases autopsied per year was noted over the 5-year study period. Diseases of the cardiovascular, respiratory and central nervous systems were responsible for the majority of natural deaths. Infectious diseases were responsible for most deaths in the youngest age group studied (18-29 years). Acute alcohol poisoning was responsible for the deaths of 35 (6%) cases, with an average blood alcohol concentration of 0.38g/100mL in these cases. Eight deaths were drug-/substance related. Waiting times for blood alcohol and toxicology results increased over the 5-year study period. No cause of death was found in 10.6% of cases. Conclusions -The questionnaire and interviewing structure could possibly be improved in order to obtain better pre-autopsy information and to reduce the number of “unnecessary” medicolegal autopsies, thereby reducing the burden of cost on the Forensic Pathology Services. / AFRIKAANSE OPSOMMING: Agtergrond – Die werkslading van die forensiese patoloog en ander personeel van die Forensiese Patologie Dienste word vermeerder deur die verwysing van moontlik onnodige natuurlike gevalle na die Forensiese Patologie Dienste. Die primêre doelwitte van die medies-geregtelike nadoodse ondersoek is beperk tot die bepaling van ‘n oorsaak van dood in vermoedelik onnatuurlike gevalle, en om nalatigheid of kriminele aksies uit te skakel. Doelwit – Om die finale uitkomste van medies-geregtelike nadoodse ondersoeke in “skielike en onverwagte” volwasse sterftes oor ‘n 5-jaar tydperk te bepaal. Metodes – ‘n Observasionele, retrospektiewe, beskrywende studie is uitgevoer. “Skielike en onverwagte” volwasse sterftes wat verwys is na Tygerberg Forensiese Patologie Dienste vanaf 1 Januarie 2001 tot 31 Desember 2005 is hersien. Inligting is versamel vanaf die nadoodse ondersoekverslae, kontemporêre notas en hospitaalnotas. Bevindinge – Agthonderd en sestien volwasse gevalle van skielike en onverwagte sterftes is oor die 5-jaar periode verwys na Tygerberg Forensiese Patologie Dienste. Volledige lykskouings is uitgevoer in 74% (601/816) van die gevalle. Die vermoedelike wyse van die sterfte was natuurlik in 79.04% en ‘n toename in die aantal natuurlike gevalle wat lykskouings ondergaan het, is waargeneem oor die 5-jaar studie tydperk. Siektes van die kardiovaskulêre, respiratoriese en sentrale senuweestelsel was verantwoordelik vir die meerderheid natuurlike sterftes. Infektiewe toestande was verantwoordelik vir die meeste sterftes in die jongste ouderdomsgroep (18-29 jaar) wat bestudeer is. Akute alkoholvergiftiging was verantwoordelik vir die sterftes van 35 (6%) gevalle, met ‘n gemiddelde bloed-alkohol-konsentrasie van 0.38g/100mL in hierdie gevalle. Agt sterftes was dwelm-/middelverwant. Die wagtyd vir bloed-alkohol en toksikologie resultate het vermeerder oof die 5-jaar studie tydperk. Die oorsaak van dood was nie gevind in 10.6% van gevalle. Afleidings – Die vraelys en onderhoud-struktuur kan moontlik verbeter word om sodoende beter inligting te verkry voor die uitvoering van ‘n lykskouing, en om die aantal “onnodige” medies-geregtelike nadoodse ondersoeke te verminder, en sodoende die kostedruk te verminder op die Forensiese Patologie Dienste.

Les canalopathies cardiaques congénitales constituent la principale hypothèse diagnostique dans les cas de mort subite inexpliquée chez les sujets de moins de 35 ans. Notre travail a eu pour objectif demettre au point une stratégie de détection post-mortem des mutations sur les gènes connus pour être impliqués dans les canalopathies cardiaques, applicable en routine, à partir de la principale source d’ADN post-mortem disponible en France à savoir les prélèvements fixés au formol et inclus en paraffine (FFIP). A partir d’une cohorte de 12 cas, deux techniques de détection de variants génétiques ont été évaluées, une technique de criblage par l’analyse des courbes de fusion haute résolution et une technique de génotypage par spectrométrie de masse MALDI-TOF, respectivement sur le gène KCNQ1 et le gène RyR2. Quelle que soit la technique utilisée, il n’est pas possible de s’affranchir du séquençage de type Sanger afin d’explorer les séquences d’intérêts qui n’ont pu être optimisées avec l’une ou l’autre des méthodes à la fois sur les prélèvements congelés et FFIP. L’arrivée des séquenceurs de nouvelles générations ouvrent ainsi de nouvelles perspectives dans ce domaine. / The congenital cardiac channelopathies constitute the principal diagnostic hypothesis in autopsynegative sudden unexplained death concerning people younger than 35 years old. The present study aimed to develop a strategy of mutations detection on known genes implicated in the cardiac channelopathies. This strategy of mutations detection had to be applicable to routine and has been studied on formalin-fixed and paraffin-embedded (FFPE) tissues which are the principal DNA source available in France. On a cohort of 12 cases, two technique of sequence variants detection wereevaluated: the screening method of High Resolution Melt and the genotyping method based on a MALDI-TOF mass spectrometry, respectively on KCNQ1 and RyR2 genes. Whatever the technique, there is a necessity of resorting to the Sanger sequencing to explore the sequence of interest none optimized with one or the other technology both on FFEP and frozen tissues. That’s why the next generation sequencing method should open new perspectives in the post-mortem diagnostic of cardiac channelopathies.

This thesis explores mothers' reactions to, and methods of dealing with, the sudden death of a child, using a constructivist approach. The study focusses on the meanings that mothers construe in relation to the sudden death of their child and the role of these constructions in her "recovery" from this loss. It also explores the grieving process, the effect of the loss on the mother, including a focus on changes in her value system, her role as a mother and as a wife, as well as the impact of this loss on the family system. The study was conducted on the basis of qualitative research methodology, making use of the case study method. The sample consisted of three mothers, selected purposively. The data gathered was analysed inductively. / Psychology / M.A.(Clinical Psychology)

Na última década, a podridão vermelha das raízes da soja (PVR), ou síndrome da morte súbita, causada pelo fungo Fusarium solani f.sp. glycines, tornou-se uma doença que é motivo de preocupação para os sojicultores, técnicos e pesquisadores nas regiões onde esta doença já foi constatada, sendo a única estratégia de controle viável a utilização de cultivares resistentes. Diante disto, o principal objetivo do presente trabalho foi o estudo do controle genético da reação da soja a PVR por meio de técnicas de genética clássica e molecular. Foi utilizada a geração F2 de um dialelo 5x5, sem os recíprocos, envolvendo cinco cultivares: Forrest, MG/BR-46 (Conquista), IAC-4, FT-Cristalina e FT-Estrela, sendo as duas primeiras mais resistentes a PVR que IAC-4, considerada moderadamente resistente e, as duas últimas, altamente suscetíveis. Além de testes de inoculação com as cultivares, foram conduzidos três experimentos com a geração F2: um em telado (semeadura em julho de 2001) e dois em casa de vegetação (semeadura em setembro de 2001 e julho de 2002), sendo os dois primeiros em blocos ao acaso e o terceiro no delineamento inteiramente casualizado. O patógeno foi inoculado com grãos de sorgo colonizados, colocando-se três grãos no fundo de cada cova, no momento da semeadura, fazendo-se cinco covas por vaso, cada qual constituindo uma parcela com cinco plantas. Em cada experimento, foram avaliadas individualmente 50 plantas de cada genitor e 150 plantas de cada cruzamento F2, entre os 30 e 40 dias após a emergência, utilizando-se uma escala de notas de 1 a 5 para a severidade dos sintomas foliares da PVR. A porcentagem de incidência da doença em cada parcela e um índice de doença também foram calculados. Nas análises de variância com os dados de médias de parcelas, observaram-se diferenças altamente significativas entre os genitores e entre populações F2 para a severidade e índice de doença dos sintomas foliares, na maioria dos casos, embora os genitores resistentes e suscetíveis não foram muito contrastantes. As cultivares Forrest e Conquista comportaram-se sempre como resistentes, e Cristalina e Estrela como suscetíveis, enquanto que IAC-4 apresentou comportamento instável. Pela análise dialélica de Jinks-Hayman reafirmou-se a influência do ambiente sobre o controle da resistência à manifestação dos sintomas foliares da PVR, a qual foi controlada quantitativamente. Nos experimentos de 2001, constatou-se apenas a ação de efeitos gênicos aditivos. Porém, no experimento conduzido em telado, a resistência demonstrou controle por genes recessivos, enquanto que na casa de vegetação, na maior parte, por genes dominantes. No experimento de 2002 constatou-se a presença de efeitos gênicos aditivos e de dominância, predominando o efeito destes últimos. Assim, com base no experimento de 2002, para o grupo de cultivares estudado, os parâmetros genéticos calculados permitiram verificar que: o grau médio de dominância indicou a presença de sobredominância; predominaram genes recessivos no grupo dos genitores; pelo menos três locos ou blocos gênicos que exibiram dominância foram responsáveis pelo controle da resistência a PVR; as herdabilidades estimadas no sentido restrito foram médias (0,33 a 0,62) e, no sentido amplo, altas (0,90 a 0,96), confirmando a presença de dominância; a resistência foi controlada, na maior parte, por genes dominantes e a ordem decrescente de dominância das cultivares foi a seguinte: 'Conquista', 'Cristalina', 'Forrest', 'Estrela' e 'IAC-4'; a exclusão de 'Cristalina', por suspeita de apresentar distribuição de genes correlacionada com 'Conquista' e 'Estrela', melhorou a adequação dos dados de índice de doença ao modelo genético aditivo-dominante de Jinks-Hayman. A utilização de cinco marcadores moleculares microssatélites (Satt163, Satt309, Satt354, Satt371 e Satt570), relatados como ligados a cinco QRLs da PVR, indicou a provável presença de multialelismo nestes locos, o que não invalidou a adequação dos dados ao modelo de Jinks-Hayman. Pela análise de ligação entre 126 indivíduos F2 do cruzamento 'Conquista' x 'Estrela' com os marcadores Satt163 e Satt354, no experimento conduzido em telado, houve ligação fraca (P<0,10) entre estes locos e os respectivos QRLs, havendo tendência dos alelos recessivos serem os responsáveis pelo controle da resistência nestes dois locos, concordando com os resultados da análise dialélica para este experimento. / In order to study the genetic control of soybean resistance to sudden death syndrome (SDS) by classical and molecular genetic techniques a 5x5 diallel with the F2 generation, without the reciprocals, was carried out. The following parents were used: 'Forrest', 'MG/BR-46 (Conquista)', 'IAC-4', 'FT-Cristalina' and 'FT-Estrela'. The first two cultivars are more resistant to SDS than 'IAC-4', that is considered to be moderately resistant to SDS, and the last two cultivars are highly susceptible. Tests of inoculation were done with the cultivars and three experiments with the F2 generation (two in 2001 and one in 2002) were carried out, all of them in greenhouses. The fungus was inoculated by three colonized sorghum grains placed at the bottom of the holes at the planting. It was used five-holes/clay pot, which one was considered a plot with five plants. In each experiment with the F2 generation 50 single plants of each parent and 150 single plants of each F2 population were evaluated between 30 and 40 days after emergency by using a scale (1 to 5) based on foliar severity symptoms. The disease incidence and a disease index also were calculated for each plot. In the ANOVAs with data plot average for severity and disease index highly significant differences were detected among the treatments in almost all cases, although the resistant and the susceptible parents did not differ too much. The parents 'Forrest' and 'Conquista' were always more resistant than the others. 'Cristalina' and 'Estrela' were the most susceptible parents, while 'IAC-4' was unstable. Jinks-Hayman's analysis reaffirmed the environment effect on the genetic control of the resistance to SDS foliar symptoms, which was quantitatively controlled. In the 2001 experiments there was observed only additive genic effects, but in one experiment recessive genes had controlled the resistance, while in the other, in major part, dominant genes had controlled the resistance to SDS. In the 2002 experiment it was showed mainly dominance effects and also some additive genic effects. In the last experiment, for the group of parents used, the genetic parameters indicated that: the average degree of dominance showed the presence of overdominance; there were more recessive than dominants genes in the group of the parents; at least three loci or genic blocks that exhibited dominance were responsible for the genetic control of the resistance to SDS; the heritability in the narrow-sense had middle values (0.33 to 0.62), and in the broad-sense had high values (0.90 to 0.96), reinforcing the presence of dominance effects; the resistance to SDS was controlled, mostly, by dominant genes; the decreasing order of dominance of the parents were: 'Conquista', 'Cristalina', 'Forrest', 'Estrela' and 'IAC-4'; and the exclusion of 'Cristalina' of the diallel for disease index by suspect of gene correlated distribution with 'Conquista' and 'Estrela' improved the fitting of the data to Jinks-Hayman's additive-dominant model. Five microsatellite markers (Satt163, Satt309, Satt354, Satt371 and Satt570), reported as linked to five SDS QRLs, were used and showed the possibility of occurrence of multiallelism in those loci, but this evidence did not invalidate the fitting of the data to Jinks-Hayman's model. The molecular analysis in 126 plants of 'Conquista' x 'Estrela' cross with the markers Satt163 and Satt354, in the first experiment of 2001, showed the tendency of weakly association (P<0,10), between those loci and the QRLs. This analysis showed also tendency that the recessive genes controlled the resistance to SDS in both loci, in according to the results obtained in the diallel analysis for this experiment.

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