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Cavalcanti DP, de Souza W. The Kinetoplast of Trypanosomatids: From Early Studies of Electron Microscopy to Recent Advances in Atomic Force Microscopy. Scanning 2018; 2018:9603051. [PMID: 30018700 PMCID: PMC6029474 DOI: 10.1155/2018/9603051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/07/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
The kinetoplast is a specialized region of the mitochondria of trypanosomatids that harbors the most complex and unusual mitochondrial DNA found in nature. Kinetoplast DNA (kDNA) is composed of thousands of circular molecules topologically interlocked to form a single network. Two types of DNA circles are present in the kinetoplast: minicircles (0.5-10 kb) and maxicircles (20-40 kb). Knowledge of kinetoplast architecture is crucial to understanding the replication and segregation of kDNA circles because the molecules involved in these processes are precisely positioned in functional domains throughout the kinetoplast. The fine structure of the kinetoplast was revealed in early electron microscopy (EM) studies. However, an understanding of the topological organization of kDNA was only demonstrated after the development of protocols to separate kDNA from nuclear DNA, followed by EM observations. Electron microscopy analysis of thin sections of trypanosomatids, spreading of isolated kDNA networks onto EM grids, deep-etching studies, and cytochemical and immunocytochemical approaches are examples of techniques that were useful for elucidating the structure and replication of the kinetoplast. Recently, atomic force microscopy has joined this set of techniques and improved our knowledge about the kDNA network and revealed new details about kDNA topology in trypanosomatids.
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Affiliation(s)
- Danielle Pereira Cavalcanti
- Laboratório de Microbiologia, Diretoria de Metrologia Aplicada às Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia-Inmetro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem and Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Wanderley de Souza
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem and Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Gonçalves CS, Ávila AR, de Souza W, Motta MCM, Cavalcanti DP. Revisiting the Trypanosoma cruzi metacyclogenesis: morphological and ultrastructural analyses during cell differentiation. Parasit Vectors 2018; 11:83. [PMID: 29409544 PMCID: PMC5801705 DOI: 10.1186/s13071-018-2664-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 01/22/2018] [Indexed: 11/30/2022] Open
Abstract
Background Trypanosoma cruzi uses several strategies to survive in different hosts. A key step in the life-cycle of this parasite is metacyclogenesis, which involves various morphological, biochemical, and genetic changes that induce the differentiation of non-pathogenic epimastigotes into pathogenic metacyclic trypomastigotes. During metacyclogenesis, T. cruzi displays distinct morphologies and ultrastructural features, which have not been fully characterized. Results We performed a temporal description of metacyclogenesis using different microscopy techniques that resulted in the identification of three intermediate forms of T. cruzi: intermediates I, II and III. Such classification was based on morphological and ultrastructural aspects as the location of the kinetoplast in relation to the nucleus, kinetoplast shape and kDNA topology. Furthermore, we suggested that metacyclic trypomastigotes derived from intermediate forms that had already detached from the substrate. We also found that changes in the kinetoplast morphology and kDNA arrangement occurred only after the repositioning of this structure toward the posterior region of the cell body. These changes occurred during the later stages of differentiation. In contrast, changes in the nucleus shape began as soon as metacyclogenesis was initiated, while changes in nuclear ultrastructure, such as the loss of the nucleolus, were only observed during later stages of differentiation. Finally, we found that kDNA networks of distinct T. cruzi forms present different patterns of DNA topology. Conclusions Our study of T. cruzi metacyclogenesis revealed important aspects of the morphology and ultrastructure of this intriguing cell differentiation process. This research expands our understanding of this parasite’s fascinating life-cycle. It also highlights the study of T. cruzi as an important and exciting model system for investigating diverse aspects of cellular, molecular, and evolutionary biology.
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Affiliation(s)
- Camila Silva Gonçalves
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, RJ, Brazil.,Laboratório de Microbiologia, Diretoria de Metrologia Aplicada às Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia- Inmetro, Rio de Janeiro, RJ, Brazil
| | - Andrea Rodrigues Ávila
- Laboratório de Regulação da Expressão Gênica, Instituto Carlos Chagas, FIOCRUZ, Curitiba, PR, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, RJ, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, RJ, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Danielle Pereira Cavalcanti
- Laboratório de Microbiologia, Diretoria de Metrologia Aplicada às Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia- Inmetro, Rio de Janeiro, RJ, Brazil. .,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Zuma AA, Cavalcanti DP, Zogovich M, Machado ACL, Mendes IC, Thiry M, Galina A, de Souza W, Machado CR, Motta MCM. Unveiling the effects of berenil, a DNA-binding drug, on Trypanosoma cruzi: implications for kDNA ultrastructure and replication. Parasitol Res 2014; 114:419-30. [DOI: 10.1007/s00436-014-4199-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/17/2014] [Indexed: 11/29/2022]
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Cavalcanti DP, Gonçalves DL, Costa LT, de Souza W. The structure of the kinetoplast DNA network of Crithidia fasciculata revealed by atomic force microscopy. Micron 2011; 42:553-9. [PMID: 21377370 DOI: 10.1016/j.micron.2011.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 01/10/2011] [Accepted: 01/27/2011] [Indexed: 11/16/2022]
Abstract
DNA is the biopolymer most studied by scanning probe methods, and it is now possible to obtain reliable and reproducible images of DNA using atomic force microscopy (AFM). AFM has been extensively used to elucidate morphological changes to DNA structure, such as the formation of knots, nicks, supercoiling and bends. The mitochondrial or kinetoplast DNA (kDNA) of trypanosomatids is the most unusual DNA found in nature, being unique in organization and replication. The kDNA is composed of thousands of topologically interlocked DNA circles that form a giant network. To understand the biological significance of the kinetoplast DNA, it is necessary to learn more about its structure. In the present work, we used two procedures to prepare kDNA networks of Crithidia fasciculata for observation by AFM. Because AFM allows for the examination of kDNA at high resolution, we were able to identify regions of overlapping kDNA molecules and sites where several molecules cross. This found support the earlier described kDNA structural organization as composed by interlocked circles. We also observed an intricate high-density height pattern around the periphery of the network of C. fasciculata, which appears to be a bundle of DNA fibers that organizes the border of the network. Our present data confirm that AFM is a powerful tool to study the structural organization of biological samples, including complex arrays of DNA such as kDNA, and can be useful in revealing new details of structures previously visualized by other means.
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Affiliation(s)
- Danielle Pereira Cavalcanti
- Laboratório de Biotecnologia, Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, Inmetro, RJ, Brazil.
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de Souza FSP, Rampazzo RDCP, Manhaes L, Soares MJ, Cavalcanti DP, Krieger MA, Goldenberg S, Fragoso SP. Knockout of the gene encoding the kinetoplast-associated protein 3 (KAP3) in Trypanosoma cruzi: effect on kinetoplast organization, cell proliferation and differentiation. Mol Biochem Parasitol 2010; 172:90-8. [PMID: 20363262 DOI: 10.1016/j.molbiopara.2010.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 03/12/2010] [Accepted: 03/26/2010] [Indexed: 11/16/2022]
Abstract
Kinetoplast DNA (kDNA) of trypanosomatid protozoa consists of an unusual arrangement of two types of circular molecules catenated into a single network: (1) a few maxicircles that encode various mitochondrial enzyme subunits and rRNA in a cryptic pattern and (2) thousands of minicircles that encode guide RNAs (gRNAs). kDNA is associated with proteins, known as kinetoplast-associated proteins (KAPs), which condense the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasite that displays different kDNA condensation patterns during its complex morphogenetic development. We cloned the T. cruzi gene encoding TcKAP3 (kinetoplast-associated protein 3). TcKAP3 is a single-copy gene that is transcribed into a 1.8-kb mRNA molecule and expressed in all stages of the parasite. Mouse antiserum raised against recombinant TcKPA3 recognized a 21.8kDa protein, which was found, by indirect immunofluorescence and immunoelectron microscopy, to be associated with the T. cruzi kinetoplast. Several features of TcKAP3, such as its small size, basic nature and similarity with KAP3 from the insect trypanosomatid Crithidia fasciculata, are consistent with a role in DNA charge neutralization and condensation. This suggests that this protein is involved in organizing the kDNA network. Gene deletion was used to investigate TcKAP3 function. Here we investigated the T. cruzi KAP3 null mutant, analyzing its fitness during proliferation, differentiation and infectivity.
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Brancati F, Bernardini L, Cavalcanti DP, Romano C, Novelli A, Dallapiccola B. Genome rearrangements in patients with blepharophimosis, mental retardation and hypothyroidism, so-called Young-Simpson syndrome. Clin Genet 2009; 76:210-3. [PMID: 19659891 DOI: 10.1111/j.1399-0004.2009.01235.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cavalcanti DP, Shimada MK, Probst CM, Souto-Padrón TCBS, de Souza W, Goldenberg S, Fragoso SP, Motta MCM. Expression and subcellular localization of kinetoplast-associated proteins in the different developmental stages of Trypanosoma cruzi. BMC Microbiol 2009; 9:120. [PMID: 19497120 PMCID: PMC2700280 DOI: 10.1186/1471-2180-9-120] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 06/04/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The kinetoplast DNA (kDNA) of trypanosomatids consists of an unusual arrangement of circular molecules catenated into a single network. The diameter of the isolated kDNA network is similar to that of the entire cell. However, within the kinetoplast matrix, the kDNA is highly condensed. Studies in Crithidia fasciculata showed that kinetoplast-associated proteins (KAPs) are capable of condensing the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasitic protozoon that shows distinct patterns of kDNA condensation during their complex morphogenetic development. In epimastigotes and amastigotes (replicating forms) the kDNA fibers are tightly packed into a disk-shaped kinetoplast, whereas trypomastigotes (non-replicating) present a more relaxed kDNA organization contained within a rounded structure. It is still unclear how the compact kinetoplast disk of epimastigotes is converted into a globular structure in the infective trypomastigotes. RESULTS In this work, we have analyzed KAP coding genes in trypanosomatid genomes and cloned and expressed two kinetoplast-associated proteins in T. cruzi: TcKAP4 and TcKAP6. Such small basic proteins are expressed in all developmental stages of the parasite, although present a differential distribution within the kinetoplasts of epimastigote, amastigote and trypomastigote forms. CONCLUSION Several features of TcKAPs, such as their small size, basic nature and similarity with KAPs of C. fasciculata, are consistent with a role in DNA charge neutralization and condensation. Additionally, the differential distribution of KAPs in the kinetoplasts of distinct developmental stages of the parasite, indicate that the kDNA rearrangement that takes place during the T. cruzi differentiation process is accompanied by TcKAPs redistribution.
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Affiliation(s)
- Danielle Pereira Cavalcanti
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Cavalcanti DP, Thiry M, de Souza W, Motta MCM. The kinetoplast ultrastructural organization of endosymbiont-bearing trypanosomatids as revealed by deep-etching, cytochemical and immunocytochemical analysis. Histochem Cell Biol 2008; 130:1177-85. [PMID: 18542983 DOI: 10.1007/s00418-008-0450-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2008] [Indexed: 11/27/2022]
Abstract
The endosymbiont-bearing trypanosomatids present a typical kDNA arrangement, which is not well characterized. In the majority of trypanosomatids, the kinetoplast forms a bar-like structure containing tightly packed kDNA fibers. On the contrary, in trypanosomatids that harbor an endosymbiotic bacterium, the kDNA fibers are disposed in a looser arrangement that fills the kinetoplast matrix. In order to shed light on the kinetoplast structural organization in these protozoa, we used cytochemical and immunocytological approaches. Our results showed that in endosymbiont-containing species, DNA and basic proteins are distributed not only in the kDNA network, but also in the kinetoflagellar zone (KFZ), which corresponds to the region between the kDNA and the inner mitochondrial membrane nearest the flagellum. The presence of DNA in the KFZ is in accordance with the actual model of kDNA replication, whereas the detection of basic proteins in this region may be related to the basic character of the intramitochondrial filaments found in this area, which are part of the complex that connects the kDNA to the basal body. The kinetoplast structural organization of Bodo sp. was also analyzed, since this protozoan lacks the highly ordered kDNA-packaging characteristic of trypanosomatid and represents an evolutionary ancestral of the Trypanosomatidae family.
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Affiliation(s)
- Danielle Pereira Cavalcanti
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Centro de Ciências da Saúde, Bloco G, subsolo, Rio de Janeiro, RJ, Brazil.
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Jehee FS, Krepischi-Santos ACV, Rocha KM, Cavalcanti DP, Kim CA, Bertola DR, Alonso LG, D'Angelo CS, Mazzeu JF, Froyen G, Lugtenberg D, Vianna-Morgante AM, Rosenberg C, Passos-Bueno MR. High frequency of submicroscopic chromosomal imbalances in patients with syndromic craniosynostosis detected by a combined approach of microsatellite segregation analysis, multiplex ligation-dependent probe amplification and array-based comparative genome hybridisation. J Med Genet 2008; 45:447-50. [PMID: 18456720 DOI: 10.1136/jmg.2007.057042] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We present the first comprehensive study, to our knowledge, on genomic chromosomal analysis in syndromic craniosynostosis. In total, 45 patients with craniosynostotic disorders were screened with a variety of methods including conventional karyotype, microsatellite segregation analysis, subtelomeric multiplex ligation-dependent probe amplification) and whole-genome array-based comparative genome hybridisation. Causative abnormalities were present in 42.2% (19/45) of the samples, and 27.8% (10/36) of the patients with normal conventional karyotype carried submicroscopic imbalances. Our results include a wide variety of imbalances and point to novel chromosomal regions associated with craniosynostosis. The high incidence of pure duplications or trisomies suggests that these are important mechanisms in craniosynostosis, particularly in cases involving the metopic suture.
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Affiliation(s)
- F S Jehee
- Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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Lourenço EE, Cavalcanti DP, Assine Picchi GF, Souza W, Aurélio Krieger M, Machado Motta MC, Goldenberg S, Perdigão Fragoso S. Molecular characterization of type II topoisomerase in the endosymbiont-bearing TrypanosomatidBlastocrithidia culicis. FEMS Microbiol Lett 2006; 257:163-70. [PMID: 16553848 DOI: 10.1111/j.1574-6968.2006.00164.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
DNA topoisomerases are involved in DNA metabolism. These enzymes are inhibited by antimicrobial and antitumoral agents and might be important targets in the chemotherapy of diseases caused by parasites. We have cloned and characterized the gene encoding topoisomerase II from the monoxenic trypanosomatid Blastocrithidia culicis (BcTOP2). The BcTOP2 gene has a 3693 nucleotide-long open reading frame that encodes a 138 kDa polypeptide. The B. culicis topoisomerase II (BctopoII) amino-acid sequence shares high similarity (>74%) with topoisomerases from other trypanosomatids, and shares a lower similarity (41%) with other eukaryotic topoisomerases II from yeast to humans. BcTOP2 is a single copy gene and encodes a 4.4 kb mRNA. Western blotting of B. culicis extracts using the antiserum raised against a C-terminal portion of BctopoII showed a 138 kDa polypeptide. Immunolocalization assays showed that the antiserum recognized the nuclear topoisomerase II.
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Jehee FS, Johnson D, Alonso LG, Cavalcanti DP, de Sá Moreira E, Alberto FL, Kok F, Kim C, Wall SA, Jabs EW, Boyadjiev SA, Wilkie AOM, Passos-Bueno MR. Molecular screening for microdeletions at 9p22-p24 and 11q23-q24 in a large cohort of patients with trigonocephaly. Clin Genet 2005; 67:503-10. [PMID: 15857417 DOI: 10.1111/j.1399-0004.2005.00438.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Trigonocephaly is a rare form of craniosynostosis characterized by the premature closure of the metopic suture. To contribute to a better understanding of the genetic basis of metopic synostosis and in an attempt to restrict the candidate regions related to metopic suture fusion, we studied 76 unrelated patients with syndromic and non-syndromic trigonocephaly. We found a larger proportion of syndromic cases in our population and the ratio of affected male to female was 1.8 : 1 and 5 : 1 in the non-syndromic and syndromic groups, respectively. A microdeletion screening at 9p22-p24 and 11q23-q24 was carried out for all patients and deletions in seven of them were detected, corresponding to 19.4% of all syndromic cases. Deletions were not found in non-syndromic patients. We suggest that a molecular screening for microdeletions at 9p22-p24 and 11q23-q24 should be offered to all syndromic cases with an apparently normal karyotype because it can potentially elucidate the cause of trigonocephaly in this subset of patients. We also suggest that genes on the X-chromosome play a major role in syndromic trigonocephaly.
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Affiliation(s)
- F S Jehee
- Centro de Estudos do Genoma Humano, Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, SP, Brazil
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Vargas FR, Schuler-Faccini L, Brunoni D, Kim C, Meloni VF, Sugayama SM, Albano L, Llerena JC, Almeida JC, Duarte A, Cavalcanti DP, Goloni-Bertollo E, Conte A, Koren G, Addis A. Prenatal exposure to misoprostol and vascular disruption defects: a case-control study. Am J Med Genet 2000; 95:302-6. [PMID: 11186881 DOI: 10.1002/1096-8628(20001211)95:4<302::aid-ajmg2>3.0.co;2-b] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prenatal exposure to misoprostol has been associated with Moebius and limb defects. Vascular disruption has been proposed as the mechanism for these teratogenic effects. The present study is a multicenter, case-control study that was designed to compare the frequency of prenatal misoprostol use between mothers of Brazilian children diagnosed with vascular disruption defects and matched control mothers of children diagnosed with other types of defects. A total of 93 cases and 279 controls were recruited in eight participating centers. Prenatal exposure was identified in 32 infants diagnosed with vascular disruption defects (34.4%) compared with only 12 (4.3%) in the control group (P<0.0000001). Our data suggest that prenatal exposure to misoprostol is associated to the occurrence of vascular disruption defects in the newborns.
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Affiliation(s)
- F R Vargas
- Hospital Universitário Gaffrée-Guinle, Universidade do Rio de Janeiro, Brazil.
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Splendore A, Silva EO, Alonso LG, Richieri-Costa A, Alonso N, Rosa A, Carakushanky G, Cavalcanti DP, Brunoni D, Passos-Bueno MR. High mutation detection rate in TCOF1 among Treacher Collins syndrome patients reveals clustering of mutations and 16 novel pathogenic changes. Hum Mutat 2000; 16:315-22. [PMID: 11013442 DOI: 10.1002/1098-1004(200010)16:4<315::aid-humu4>3.0.co;2-h] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Twenty-eight families with a clinical diagnosis of Treacher Collins syndrome were screened for mutations in the 25 coding exons of TCOF1 and their adjacent splice junctions through SSCP and direct sequencing. Pathogenic mutations were detected in 26 patients, yielding the highest detection rate reported so far for this disease (93%) and bringing the number of known disease-causing mutations from 35 to 51. This is the first report to describe clustering of pathogenic mutations. Thirteen novel polymorphic alterations were characterized, confirming previous reports that TCOF1 has an unusually high rate of single-nucleotide polymorphisms (SNPs) within its coding region. We suggest a possible different mechanism leading to TCS or genetic heterogeneity for this condition, as we identified two families with no apparent pathogenic mutation in the gene. Furthermore, our data confirm the absence of genotype-phenotype correlation and reinforce that the apparent anticipation often observed in TCS families is due to ascertainment bias.
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Affiliation(s)
- A Splendore
- Centro de Estudos do Genoma Humano, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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Abstract
We describe an infant with Dandy-Walker malformation and tetramelic postaxial polydactyly type 1A. Parental consanguinity reinforces previous suggestions for autosomal recessive inheritance.
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Affiliation(s)
- D P Cavalcanti
- Depto. Genética Médica, Faculdade de Ciências Médicas, UNICAMP, Campinas, SP, Brazil.
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Castilla EE, Ashton-Prolla P, Barreda-Mejia E, Brunoni D, Cavalcanti DP, Correa-Neto J, Delgadillo JL, Dutra MG, Felix T, Giraldo A, Juarez N, Lopez-Camelo JS, Nazer J, Orioli IM, Paz JE, Pessoto MA, Pina-Neto JM, Quadrelli R, Rittler M, Rueda S, Saltos M, Sánchez O, Schüler L. Thalidomide, a current teratogen in South America. Teratology 1996; 54:273-7. [PMID: 9098920 DOI: 10.1002/(sici)1096-9926(199612)54:6<273::aid-tera1>3.0.co;2-#] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Thalidomide, mainly used for the treatment of leprosy, is a current teratogen in South America, and it is reasonable to assume that at present this situation is affecting many births in underdeveloped countries. Moreover, the potential re-marketing of thalidomide for the treatment of a large variety of diseases may extend the problem to the developed world. When the drug is available, the control of its intake during early pregnancy is very difficult since most pregnancies are unintended. The ongoing occurrence of thalidomide embryopathy cases went undetected by the ECLAMC, due to several factors: (1) low populational coverage through this monitoring system; (2) pre-existence of the teratogen with its effects present in both baseline (expected) and monitored (observed) materials; and (3) lack of a defined phenotype to be monitored. Thus, if thalidomide re-enters the market throughout the world, due to the wide range of new applications, occurrence of phocomelia alone might not be sufficient to detect its effects. By a case-reference approach, the ECLAMC registered 34 thalidomide embryopathy cases born in South America after 1965 whose birthplaces correspond to endemic areas for leprosy. Phocomelia was found in five of eleven fully described cases. Thus, phocomelia alone is neither specific nor sufficient to serve as a suitable phenotype to survey the teratogenic effects of thalidomide. Therefore, a thalidomide-like phenotype, defined as any bilateral upper and/or lower limb reduction defect of the preaxial and/or phocomelia types, should be included in the routine surveillance of birth defects in all programmes.
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Affiliation(s)
- E E Castilla
- ECLAMC Departmento de Genetica, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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Abstract
OBJECTIVE Limb reduction defects were considered as possible indicators of environmental teratogenesis; it was suggested that also invasive prenatal procedures could increase the risk for limb reduction defects. The purpose of this work is to give a baseline frequency for limb reduction defects, using data from a population not exposed to prenatal diagnosis procedures. DESIGN Using data collected in the period 1967 to 1992 within the frame of the Latin American Collaborative Study of Congenital Malformations which clinically examined 2,917,074 newborn infants, a total of 1715 with limb reduction defects were found. All cases were classified and analysed in 25 categories. Geographic differences in recorded rates were tested by chi 2 for homogeneity. Secular trends were analysed using chi 2 test for linear trends. RESULTS The overall birth prevalence rate of limb reduction defects among liveborn infants was 4.91(per 10,000 births) (3.05 for isolated and 1.85 for associated cases). For stillbirths, the total prevalence was 26.73/10,000 (5.53 for isolated and 21.20 for associated cases). The inclusion of the brachydactylies increased those figures to 5.55/10,000 (3.39 for isolated and 2.16 for associated cases), and 27.42, respectively, (5.53 for isolated and 21.89 for associated cases). When isolated and associated cases were considered together, a geographic heterogeneity was found in pre-axial limb reduction defects; there was also some heterogeneity for amputations. A maternal age effect was found for the isolated hypoplasias. Standardising by maternal age, the overall prevalence of limb reduction in liveborn infants was 5.66 per 10,000 (95% CI = 5.38-5.93). An increasing trend was suggested by the isolated form of distal amputations which involved hands, feet, or digits. CONCLUSIONS Our data suggest that clustering limb reduction defects in wide groups as transverse and longitudinal may lead to heterogeneous entities. When a possible association is suspected, it would be preferable to present and analyse data in the most discriminant form available. Due to the maternal age effect, it would be advisable to standardise the rates of transversal limb reduction defects by this variable.
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Affiliation(s)
- E E Castilla
- Departamento de Genetica, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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17
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Farah SB, Ramos CF, de Mello MP, Sartorato EL, Horelli-Kuitunen N, Lopes VL, Cavalcanti DP, Hackel C. Two cases of Y; autosome translocations: A 45,X male and a clinically trisomy 18 patient. Am J Med Genet 1994; 49:388-92. [PMID: 8160730 DOI: 10.1002/ajmg.1320490407] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report on 2 cases of Y; autosome translocations. One is a male with normal external genitalia and 45,X karyotype without evidence of mosaicism or apparent translocation on cytogenetic analysis. In situ hybridization showed that the euchromatic portion of the Y-chromosome is translocated to the chromosome 15. The other case is a clinically trisomy 18 male patient, with modal number of 46, a small metacentric marker with appearance of an i(18p) and cytogenetic and molecular evidence of Y;18 translocation. The occurrence of Y;18 translocation associated with clinical signs of trisomy 18 is reported here for the first time.
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Affiliation(s)
- S B Farah
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Brazil
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18
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Mastroiacovo P, Botto LD, Cavalcanti DP, Lalatta F, Selicorni A, Tozzi AE, Baronciani D, Cigolotti AC, Giordano S, Petroni F. Limb anomalies following chorionic villus sampling: a registry based case-control study. Am J Med Genet 1992; 44:856-64. [PMID: 1481865 DOI: 10.1002/ajmg.1320440639] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Using data from the Italian Multicentric Birth Defect Registry a case-control study was performed to verify if chorionic villus sampling (CVS) was associated with transverse limb defects (TLD), with or without features of oro-mandibular-limb hypogenesis complex (OMLHC), in the exposed offspring. The results show that the risk of TLD and OMLHC is increased following CVS, and is particularly high for CVS performed early in pregnancy, i.e., under 70 days of gestational age. These results, together with a review of other epidemiologic studies, biological data and clinical reports, strongly suggest a causative role of CVS as a risk factor for TLD and indicate that at this stage CVS before 70 days of gestational age should be discouraged as an option for prenatal diagnosis and that all patients wishing to undergo CVS should be informed about the possible risk of the procedure.
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Affiliation(s)
- P Mastroiacovo
- Department of Pediatrics, Catholic University, Rome, Italy
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19
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de Sá MF, de Moura MD, Ferriani RA, Velludo MA, Soares LR, Cavalcanti DP. Association of microscopic gonadoblastoma and contralateral ovarian fibroadenoma in patients with gonadal dysgenesis and Turner phenotype. Gynecol Obstet Invest 1990; 30:186-8. [PMID: 2265807 DOI: 10.1159/000293265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A rare case of microscopic gonadoblastoma associated with gonadal fibroadenoma in a patient with gonadal dysgenesis and Turner phenotype is reported. The higher incidence of tumor pathologies in patients with gonadal dysgenesis presenting a Y chromosome in their karyotype is discussed, and the need for judicious microscopic analysis of the gonadal streaks of these patients for the detection of possible incipient tumors is emphasized.
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Affiliation(s)
- M F de Sá
- Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
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20
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Abstract
Young and Simpson in 1987 and Fryns and Moerman in 1988 each reported a case of a new unknown syndrome with hypothyroidism, severe global retardation, and abnormal facies, including microcephaly, blepharophimosis, bulbous nose, thin upper lip, low set ears, and micrognathia. A male infant with a similar pattern of malformations and postaxial polydactyly is reported here.
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Affiliation(s)
- D P Cavalcanti
- Departamento de Genética Médica, FCM, UNICAMP, SP, Brazil
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21
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Cavalcanti DP, Ferrari I, de Almeida JC, de Pina Neto JM, de Oliveira JA. Tetrasomy 9p caused by idic (9) (pter----q13----pter). Am J Med Genet 1987; 27:497-503. [PMID: 3631125 DOI: 10.1002/ajmg.1320270303] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cytogenetic investigation on a malformed male infant showed an extra chromosome similar to chromosome 9 in all metaphases studied. GTG, CBG, and G-11 staining suggested that the extra chromosome was an abnormal 9, permitting the identification of the chromosome constitution as 47,XY,+idic (9) (pter----q13----pter).
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