Detection of genomic instability by microarray-based comparative genomic hybridization (array CGH) in dysmorphic fetuses

Orientador: Ricardo BariniTese (doutorado) - Universidade Estadual de Campinas. Faculdade de Ciências MédicasResumo: Introdução: Para uma parcela significativa de fetos com defeitos congênitos o diagnóstico sindrômico permanece indefinido, dificultando a abordagem perinatal, o estabelecimento de prognóstico e o aconselhamento genético. A incapacidade de detecção de pequenas instabilidades genômicas, atualmente apontadas como provável fator causal nestas condições dismórficas, é a principal limitação do estudo cromossômico microscópico pelo bandamento G (cariótipo convencional). A hibridização genômica comparativa (comparative genomic hybridization-CGH) é capaz de identificar perdas e ganhos de material genômico com alta resolução, sem envolver o cultivo celular e o conhecimento prévio da região genômica envolvida. Objetivo: Avaliar a aplicabilidade da técnica de array CGH em sangue fetal para o diagnóstico de perdas e ganhos genômicos em um grupo de fetos dismórficos. Sujeitos/Método: Foi realizado um estudo prospectivo descritivo a partir de amostras sanguíneas de fetos dismórficos e com cromossomos numericamente normais ao bandamento G, admitidos no Setor de Medicina Fetal do Centro de Atenção Integral à Saúde da Mulher (CAISM) da Universidade Estadual de Campinas (Unicamp). Foi realizada a caracterização da amostra estudada e uma análise descritiva dos achados moleculares através da técnica de array CGH. Resultados: Foram incluídos no estudo 50 fetos, dos quais 49 preencheram os critérios de qualidade da técnica. A taxa de detecção de alterações cromossômicas pela técnica de array CGH não detectadas pelo cariótipo convencional foi de 93,7% (45 fetos), e 27% foram consideradas significativas dos pontos de vista citogenético e clínico. Entre os fetos com alterações do número de cópias, 87% apresentaram pelo menos um clone para o qual já estão descritas variações do número de cópias (CNV) em indivíduos fenotipicamente normais. Adicionalmente, a técnica mostrou-se eficaz para o esclarecimento diagnóstico da origem, exata localização e dimensionamento do material adicional encontrado em um feto com anomalia cromossômica estrutural. Conclusões: A caracterização do perfil genômico por array CGH de fetos com defeitos congênitos permitiu complementar o diagnóstico citogenético convencional, aumentando a definição diagnóstica e a identificação de regiões cromossômicas associadas a algumas anomalias congênitasAbstract: Introduction: A great number of fetuses with congenital defects remain without definitive diagnosis, making difficult the perinatal management, the prognosis establishment and the genetic counseling. The incapacity of detection of short sequence copy number changes, pointed as a probable etiology factor for some congenital defects, is the main limitation of routine G-banding. The Comparative Genomic Hybridization (CGH) overcome this limitation, and also does not require cellular culture or prior knowledge of the involved genomic region. Objective: To evaluate the applicability of the CGH method on fetal material for genomic gains and losses in a group of malformed fetuses. Methods: On a prospective descriptive study, fetal blood samples were collected from malformed fetuses with numerically normal chromosomes at G-banded karyotype, at the Fetal Medicine Unit of the Centro de Atenção Integral à Saúde da Mulher (CAISM) of the Universidade Estadual de Campinas (UNICAMP). Sample characterization and a descriptive analysis of the CGH-based technique results were accomplished. Results: Fifty fetuses were included in this study and 49 were considered optimal according to adopted quality control criteria. The detection rate of fetuses with copy number imbalances not detected by the G-banded karyotype was 93.7% (45 fetuses), with 27% of cytogenetic and clinical significance. Among fetuses with copy number imbalances, 87% presented at least one abnormal clone encompassing CNVs described for phenotipically normal individuals. Additionally, the array CGH showed to be effective for the identification of the additional genetic material origin, with its precise location and size, presented in one fetus with structural chromosomal anomaly. Conclusions: The genomic profile characterization of malformed fetuses through array CGH allowed complementing the conventional cytogenetic diagnosis, obtaining a higher precise diagnosis and the identification of chromosomal regions associated with some congenital anomaliesDoutoradoTocoginecologiaDoutor em Tocoginecologi

Genomic Imbalances Detected Through Array Cgh In Fetuses With Holoprosencephaly.

Holoprosencephaly (HPE) is heterogeneous in pathogenesis, integrating genetic susceptibility with the influence of environmental factors. Submicroscopic aberrations may contribute to the etiology of HPE. Our aim was to report the molecular analysis of 4 fetuses with HPE and normal metaphase karyotype. A whole genome BAC-array based Comparative Genomic Hybridization (array CGH) was carried out in fetal blood samples. All potential cytogenetic alterations detected on the arrays were matched against the known copy number variations databases. The array CGH analysis showed copy number gains and losses in all cases. We found a recurrent deletion in 15q14 (clone RP11-23J11) and in 15q22 (clone RP11-537k8) in 2 out 4 cases analyzed. We also observed submicroscopic gain in 6p21 in 3 out of 4 fetuses in nearby clones. All these regions were tested in known databases and no copy number variations have been described for them. This is the first report of molecular characterization through a whole genome microarray CGH of fetuses with HPE. Our results may contribute to verify the effectiveness and applicability of the molecular technique of array CGH for prenatal diagnosis purposes, and contributing to the knowledge of the submicroscopic genomic instability characterization of HPE fetuses.693-

Anencephaly: Do the Pregnancy and Maternal Characteristics Impact the Pregnancy Outcome?

Objective. To describe the characteristics of obstetric and perinatal outcome of a group of pregnancies complicated by an anencephalic fetus. Methods. Observational study including anencephalic fetuses, divided into groups according to the evolution of pregnancy: elective termination of pregnancy ETP; stillbirths (SBs); live births (LBs), and loss of follow-up. After a univariate description of the sample, some variables were compared using statistical tests. Results. 180 anencephalic fetuses were included. The mean maternal age was 25.3 years. In 71 fetuses (39%) were found additional anomalies. Comparing the groups, no statistical differences in maternal age (P = 0.5315), parity (P = 0.6070), number of previous abortion (P = 0.7464), fetal sex (P = 0.0502) and additional anomalies (P = 0.186) were found. Among those fetuses whose parents opted for continuation of pregnancy (n = 53), 20 spontaneous intrauterine deaths occurred (38%) and 33 were live births (62%). The average postnatal survival time was 51 minutes. There was no association between survival time and gestational age (P = 0.6125) or the presence of additional malformations (P = 0.1948). Conclusion. Results presented here could contribute to a better understanding of the natural history of this malformation, allowing obstetricians a more detailed discussion with the families

Instabilidades genômicas detectadas através de array CGH em fetos com holoprosencefalia

OBJECTIVE: Holoprosencephaly (HPE) is heterogeneous in pathogenesis, integrating genetic susceptibility with the influence of environmental factors. Submicroscopic aberrations may contribute to the etiology of HPE. Our aim was to report the molecular analysis of 4 fetuses with HPE and normal metaphase karyotype. METHOD: A whole genome BAC-array based Comparative Genomic Hybridization (array CGH) was carried out in fetal blood samples. All potential cytogenetic alterations detected on the arrays were matched against the known copy number variations databases. RESULTS: The array CGH analysis showed copy number gains and losses in all cases. We found a recurrent deletion in 15q14 (clone RP11-23J11) and in 15q22 (clone RP11-537k8) in 2 out 4 cases analyzed. We also observed submicroscopic gain in 6p21 in 3 out of 4 fetuses in nearby clones. All these regions were tested in known databases and no copy number variations have been described for them. CONCLUSION: This is the first report of molecular characterization through a whole genome microarray CGH of fetuses with HPE. Our results may contribute to verify the effectiveness and applicability of the molecular technique of array CGH for prenatal diagnosis purposes, and contributing to the knowledge of the submicroscopic genomic instability characterization of HPE fetuses.OBJETIVO: Holoprosencefalia (HPE) é uma malformação heterogênea na patogênese, integrando a suscetibilidade genética com a influência de fatores ambientais. Aberrações submicroscópicas podem contribuir para a etiologia da HPE. Nosso objetivo foi relatar a análise molecular de 4 fetos com HPE e cariótipo normal. MÉTODO: Foi realizado um estudo descritivo prospectivo dos achados da técnica de hibridação genômica comparativa baseada em microarranjos utilizando BAC clones de ampla cobertura genômica (BAC-array CGH) em amostras sanguíneas de fetos portadores de holoprosencefalia e com cromossomos numericamente normais ao bandamento G. Todas as potenciais alterações citogenéticas detectadas foram comparadas com bancos de dados com variações do número de cópias conhecidas. RESULTADOS: A análise de array CGH evidenciou ganhos e perdas do número de cópias em todos os 4 casos. Foram encontradas deleções recorrentes em 15q14 (clone RP11-23J11) e em 15q22 (clone RP11-537k8) em 2 dos 4 casos analisados. Observou-se em 3 fetos ganho genômico na região 6p21 em clones próximos. Todas estas regiões não apresentaram variações do número de cópias descritas em bancos de dados conhecidos. CONCLUSÃO: Este é o primeiro relato de caracterização molecular através de um microarray CGH de fetos com HPE. Nossos resultados podem contribuir para verificar a eficácia e aplicabilidade da técnica molecular de array CGH para fins de diagnóstico pré-natal, contribuindo para o conhecimento da caracterização de instabilidades genômicas submicroscópicas de fetos com HPE.3

[fetal Myelomeningocele And The Potential In-utero Repair: Follow-up Of 58 Fetuses].

Prenatal diagnosis of myelomeningocele (MM) allows planning its management and, recently, a possible in utero repair. To describe the perinatal outcome of fetuses with MM, in a Fetal Medicine Unit, identifying possible candidates for the in utero surgical repair. Retrospective and descriptive study of 58 cases of prenatally diagnosed MM, at CAISM-UNICAMP, from January 1997 to December 2001, identifying possible fetal candidates for in utero repair. the diagnosis mean gestational age was 29 weeks (17-39); level of lesions was above sacral region in 85%, association with hydrocephaly in 86%. Surgical complications were present in 39% of the neonates. During follow-up, 98% presented neurogenic bladder and 60% neurological/mental handicap. Twenty eight fetuses (42%) could have indication of in utero repair. MM is associated with severe and frequent poor results. Almost one third of our cases could had fetal repair as a treatment choice.62487-9

Fetal myelomeningocele and the potential in-utero repair: follow-up of 58 fetuses

INTRODUCTION: Prenatal diagnosis of myelomeningocele (MM) allows planning its management and, recently, a possible in utero repair. OBJECTIVE: To describe the perinatal outcome of fetuses with MM, in a Fetal Medicine Unit, identifying possible candidates for the in utero surgical repair. METHODO: Retrospective and descriptive study of 58 cases of prenatally diagnosed MM, at CAISM-UNICAMP, from January 1997 to December 2001, identifying possible fetal candidates for in utero repair. RESULTS: the diagnosis mean gestacional age was 29 weeks (17-39); level of lesions was above sacral region in 85%, association with hydrocephaly in 86%. Surgical complications were present in 39% of the neonates. During follow-up, 98% presented neurogenic bladder and 60% neurological/mental handicap. Twenty eight fetuses (42%) could have indication of in utero repair. CONCLUSION: MM is associated with severe and frequent poor results. Almost one third of our cases could had fetal repair as a treatment choice.INTRODUÇÃO: O diagnóstico pré natal da meningomielocele (MM) permite melhor planejamento de sua abordagem e, mais recentemente , um possível reparo intra-útero. OBJETIVO: Descrição da evolução perinatal de fetos com MM, acompanhados em um centro de referência em Medicina Fetal, identificando os possíveis fetos candidatos à cirurgia intra-uterina. MÉTODO: Análise retrospectiva descritiva de 58 casos de MM fetal, atendidos no CAISM-UNICAMP, de janeiro de 1997 a dezembro de 2001, identificando-se os casos cuja indicação de cirurgia fetal seria possível. RESULTADOS: Média da idade gestacional ao diagnóstico de 29 semanas (17-39); nível da lesão acima da região sacral em 85%; associação com hidrocefalia em 86%; taxa de complicações cirúrgicas de 39%. Na evolução, 98% apresentaram bexiga neurogênica e 60% deficiência neuro-mental. O potencial reparo intra-útero foi de 42%. CONCLUSÃO: MM está associada a graves e frequentes sequelas. Quase um terço dos nossos casos poderiam ter tido a cirurgia fetal como opção terapêutica.48749