Chromosomal abnormalities are defined as changes in the chromosome structure and fall in one of two categories. The first category is numerical alterations while the second category consists of structural abnormalities. Structural chromosomal abnormalities do not always interrupt genes in order to cause disease. They can also affect gene expression by separating a gene and its promoter element from distant regulatory elements. We have used characterisation of structural chromosomal abnormalities to identify the genetic bases for several congenital disorders. In papers I-III, we have applied molecular characterisation of chromosomal translocations in order to identify candidate genes involved in mental retardation, hypospadias and anal malformation and premature ovarian failure. In paper I, we localised the chromosome X translocation breakpoint in a t(X;15) to be in the immediate proximity of the gene ZDHHC15 in a patient with severe mental retardation. Subsequent experiments revealed loss of ZDHHC15 transcription in the patient which suggests this gene to be involved in the aetiology of the patient’s phenotype. In paper II, we show that a balanced translocation between chromosomes 6 and 17 in a patient with urogential malformation disrupts 2 genes, one at each translocation breakpoint. We also identified a fusion-gene as a result of the translocation. Our hypethesis is that the translocation together with its molecular consequences is important for the phenotype in the patient. Similarly, in paper III, we have used molecular characterisation of the breakpoints in a balanced translocation between chromosomes X and 11 in order to localise candidate genes in ovarian function. Our results indicate a number of genes affected by the translocation. In paper IV, we have used array-based comparative genomic hybridisation (array-CGH) in order to investigate a cohort of autistic sib-pairs for submicroscopic chromosomal alterations. We have identified several novel duplications and one novel deletion with strong association with autism.

Made available in DSpace on 2014-06-11T19:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-17Bitstream added on 2014-06-13T20:54:04Z : No. of bitstreams: 1 freitas_pc_me_sjrp.pdf: 528091 bytes, checksum: d630cd8e1a7a4fdc34c7e9200a36b8b5 (MD5) / Síndromes Mielodisplásicas (SMD) compreendem um conjunto heterogêneo de doenças hematopoéticas caracterizadas por hematopoese ineficaz, que geralmente apresentam citopenias no sangue periférico, medula óssea hipercelular, diferenciação celular displásica e propensão ao desenvolvimento de leucemia mielóide aguda. São classificadas em oito tipos e a incidência anual é estimada entre dois e 12 casos por 100.000 pessoas da população em geral e em até 50 casos por 100.000 indivíduos com idades superiores a 60 anos. A análise cromossômica das células da medula óssea dos doentes ao diagnóstico detecta alterações diretamente relacionadas com o prognóstico em aproximadamente 50% dos casos. Alguns genes também foram relacionados à etiologia e prognóstico das mielodisplasias. O gene FOXO3, um supressor de tumor, embora não estudado anteriormente em SMD, é um dos genes que mais se expressam no tecido hematopoético normal. Alterações neste gene poderiam resultar em hematopoese anormal, pois já foram relacionadas a outros tipos de câncer, com mutações descritas no éxon 1. O objetivo deste trabalho foi estudar células da medula óssea de doentes com SMD de qualquer tipo, ao diagnóstico, para investigar a presença de alterações cromossômicas e de mutações no éxon 1 do FOXO3. A análise citogenética foi realizada em metáfases submetidas ao bandamento GTG, obtidas de culturas de curta duração de células da medula, sem estimulação mitogênica. Para a análise molecular foi extraído o DNA, realizada a amplificação gênica pela Reação em Cadeia da Polimerase e realizado o sequenciamento direto do éxon 1. Entre os 25 casos analisados, três (12%) apresentaram alterações cromossômicas clonais isoladas: deleção intersticial do braço longo do cromossomo 5; monossomia do cromossomo 21 e monossomia do cromossomo 22. Todas puderam ser relacionadas... / Myelodysplastic syndrome (MDS) constitute a heterogeneous group of hematopoietic diseases characterized by ineffective hematopoiesis usually with peripheral blood cytopenia, hypercellular bone marrow, dysplastic differentiation and a tendency to evolve to acute myeloid leukemia. They are classified in eight categories by the World Health Organization. The annual incidence is estimated at between two and 12 cases per 100,000 individuals in the general population and up to 50 cases per 100,000 of over 60-year olds. A chromosomal analysis of bone marrow cells at diagnosis identifies changes directly related to prognosis in approximately 50% of cases. Additionally, some genes are also associated to the etiology and prognosis of myelodysplasia. Although not previously studied in respect to MDS, a tumor suppressor, FOXO3, is one of the most commonly expressed genes in normal hematopoietic tissue. Changes in this gene could therefore result in abnormal hematopoiesis, as mutations described in exon 1 have already been associated with other types of cancer. The aim of this study was to investigate chromosomal alterations and mutations in exon 1 of FOXO3 in bone marrow cells from patients diagnosed with any type of MDS. Cytogenetic analysis was performed on metaphases submitted to GTG banding, obtained from short-term cultures of bone marrow cells without mitogenic stimulation. To evaluate mutations in the FOXO3 gene, DNA was extracted from the bone marrow, gene amplification was achieved by polymerase chain reaction and direct sequencing was performed. Of the 25 cases analyzed, three (12%) showed clonal chromosomal abnormalities in isolation characterized as the interstitial deletion of the long arm of chromosome 5, monosomy 21 and monosomy 22. All were correlated to the diagnosis and/or prognosis of patients. No mutations were detected in exon 1, but the 159C>T polymorphism was detected... (Complete abstract click electronic access below)

Objetivos: avaliar a contribuição do fluxo anormal no ducto venoso de 11 a 13 6/7 semanas no rastreamento de anomalias cromossômicas, defeitos estruturais e prognóstico gestacional. Método: 1221 gestações únicas foram submetidas a Dopplervelocimetria do ducto venoso após o rastreamento pela translucência nucal (TN). Resultados: os defeitos cromossômicos foram diagnosticados em 22 fetos. O fluxo no ducto venoso estava anormal em 84 fetos, a TN estava acima do 95o percentil em 160 casos e ambos marcadores estiveram anormais em 41 fetos. A sensibilidade, especificidade, valores preditivos positivo e negativo para defeitos cariotípicos corresponderam respectivamente a 86,4%, 86,9%, 11,9% e 99,7% considerando a TN aumentada, 68,2%, 96,9%, 31,3%, 99,3% para anomalias do fluxo do ducto venoso e 68,2%, 97,6%, 36,6%, 99,3% analisando ambos os marcadores. Investigando malformações estruturais, esses valores foram de 43,8%, 92,9%, 8,3%, 99,1% para uma TN aumentada, 25%, 92,6%, 4,8%, 98,8% para anomalias do fluxo do ducto venoso e 25%, 97,9%, 15,4%, 98,9% para ambos os marcadores. Nos casos com TN aumentada, a proporção de nascidos vivos morfológica e cariotipicamente normais diminui de 93,8% nos fetos com fluxo no ducto venoso normal para 77,3%, quando anormal. Conclusão: a avaliação do ducto venoso de 11 a 13 6/7 semanas de gestação pode ser utilizada no rastreamento de anomalias cromossômicas fetais e pode ajudar a reduzir a taxa de falso-positivo quando combinado com a medida da TN. Em fetos com TN aumentada o fluxo anormal no ducto venoso aumenta a probabilidade de resultados gestacionais adversos / Objective: To evaluate the association between abnormal ductus venosus at 11 - 13 6/7 weeks\' gestation and chromosomal abnormalities, structural defects and fetal outcome. Methods: Ductus venosus waveform (DVFVW) and nuchal translucency (NT) thickness were prospectively evaluated in 1221 singleton pregnancies. Results: The DVFVW was abnormal in 84 cases, NT was above the 95th centile in 160 cases and both markers were observed in 41 fetuses. Chromosomal defects were diagnosed in 22 fetuses. The sensitivity, specificity and positive predictive values for an abnormal karyotype were respectively 86.4%, 86.9%, 11.9% for an increased NT; 68.2%, 96.9%, 31.3% for DVFVW abnormalities and 68.2%, 97.6%, 36.6% for both markers. Regarding structural defects, this values were 43.8%, 92.9%, 8.3% for an abnormal NT, 25%, 92.6%, 4.8% for DVFVW abnormalities and 25%, 97.9%, 15.4% for both. Considering those cases of unexplained fetal demise, the percentages were 44.4%, 85.9%, 5% for NT abnormalities, 22.2%, 92.6%, 4.8% for an abnormal DVFVW and 22.2%, 98%, 15.4% for both. In cases with increased NT measurement, the percentage of livebirths with normal karyotype and no major fetal structural defects decreased from 93.8% in normal DVFVW fetuses to 77.3%, when abnormal. Conclusion: Ductus venosus assessment at 11 - 13 6/7 weeks\' gestation is useful in screening for fetal chromosomal abnormalities and may help to reduce the false-positive rate when combining with NT thickness measurement. Abnormal DVFVW is also associated with an increase of adverse perinatal outcome in fetuses with enlarged NT. However, the value of DVFVW assessment in cases with normal NT measurement is unclear

Objetivos: Investigar possíveis alterações citogenéticas, através da técnica de bandamento de alta resolução, em indivíduos com anomalias craniofaciais associadas ao atraso no desenvolvimento neuropsicomotor e sem diagnóstico clínico-genético definido, com cariótipo (com bandas) prévio normal e estabelecer possível correlação entre o fenótipo dos indivíduos e as regiões cromossômicas alteradas. Local de execução: Laboratório de Citogenética Humana e Serviço de Genética Clínica, HRAC-USP, Bauru-SP. Indivíduos estudados e Resultados: O cariótipo de alta resolução de 16 indivíduos com anomalias craniofaciais associadas ao atraso no desenvolvimento neuropsicomotor pertencentes ao HRAC-USP, Bauru permitiu detectar alterações citogenéticas estruturais em 4 (25%) dos 16 indivíduos. Em 3 indivíduos detectou-se deleções em regiões subteloméricas (cromossomos 4p, 9p e 18q) e, em 1 indivíduo detectou-se adição de segmento cromossômico de origem desconhecida na região telomérica do cromossomo 12p. Conclusões: A frequência alta (25%) de alterações cromossômicas estruturais em regiões cromossômicas terminais (teloméricas e subteloméricas) mostra que a técnica de alta resolução é útil na identificação de alterações nessas regiões, portanto, indivíduos com anomalias craniofaciais e atraso mental, sem diagnóstico genético-clínico definido, cujo cariótipo convencional foi normal, devem ser, submetidos à análise dos cromossomos por meio do cariótipo de alta resolução antes do procedimento de CGHarray. / Objective: To investigate possible cytogenetic abnormalities through high resolution banding technique in individuals with craniofacial anomalies presenting previous normal karyotype, associated to neuropsychological development delay, without clinic-genetic diagnoses, and establish possible correlation between phenotype and possible candidate chromosomal regions. Local: Human Cytogenetic Laboratory and Clinical Genetic Service, HRAC-USP, Bauru, SP. Individuals and Results: High resolution karyotype of 16 individuals with craniofacial anomalies associated to neuropsychological development delay in follow-up at the HRAC-USP, Bauru allowed the detection of structural chromosomal abnormalities in 4 (25%) of them. Three individuals presented deletion in the subtelomeric region (chromosomes 4p, 9p, and 18q), and one individual presented an addition of an unknown chromosomal fragment in the telomeric region of chromosome 12p. Conclusions: The high frequency (25%) of structural chromosomal abnormalities in terminal region (telomeric and subtelomeric) shows that the high resolution technique is useful for identification of structural anomalies in these regions. Therefore, individuals with craniofacial anomalies associated to neuropsychological development delay without a definitive clinic-genetic diagnoses presenting a normal conventional karyotype, should be submitted to chromosomal analysis through high resolution karyotype before CGH-array procedure.

Em estudos etiológicos sobre a deficiência mental (DM), as anomalias cromossômicas, tanto numéricas quanto estruturais, são fatores que apresentam frequência relativa significante. O objetivo deste trabalho foi estudar as frequências e os tipos de anomalias cromossômicas em afetados por DM nas APAEs (Associação de Pais e Amigos dos Deficientes) de Batatais, Altinópolis e Serrana, objetivando conhecer melhor a contribuição destas anomalias na DM nessa região, caracterizando os tipos e as freqüências das aberrações cromossômicas observadas e compará-las entre as APAEs. Pacientes com suspeita de anomalias cromossômicas foram selecionados para o estudo. O critério usado para a seleção da amostra foi a realização do cariótipo em todos os afetados por DM com anomalias estruturais maiores e/ou menores. A análise citogenética foi feita através de cultura de linfócitos do sangue periférico e a coloração utilizada foi banda G, sendo analisadas 20 metáfases por paciente. Dos 505 indivíduos avaliados nas três APAES, 265 realizaram estudo citogenético, sendo encontradas 61 alterações cromossômicas (12,1% do total e 23,0% dos selecionados para cariótipo). Na APAE de Batatais, dos 305 indivíduos avaliados, 174 realizaram cariótipo, sendo encontradas 33 (10,8% do total) anomalias cromossômicas. Em Altinópolis, dos 107 indivíduos avaliados, 54 realizaram cariótipo, sendo observados 16 cariótipos anômalos (14,9% do total). Na APAE de Serrana, dos 93 indivíduos avaliados, 37 realizaram cariótipo, sendo encontradas 12 (12,9% do total) anomalias cromossômicas. Esses resultados demonstram que anomalias cromossômicas contribuem significativamente para a etiologia da DM e que a citogenética clássica possui importantes implicações na prática médica para o diagnóstico dos indivíduos afetados, assim como, para o aconselhamento genético das famílias. Além disso, observa-se que a APAE de Batatais, por apresentar uma porcentagem menor de indivíduos afetados por DM grave, 60,7%, possui uma menor incidência de anomalias cromossômicas quando comparada as APAEs de Altinópolis e Serrana que apresentam uma frequência de 87,8% e 83,9% de indivíduos com DM grave, respectivamente, indicando que alterações cromossômicas são mais frequentes em indivíduos afetados por DM grave. / In etiological studies on mental retardation (MR), the chromosomal abnormalities, both numerical and structural, are factors that have significant relative frequencies. The objective was to study the frequencies and types of chromosomal abnormalities in patients affected by MR in APAEs (Associação de Pais e Amigos dos Deficientes) of Batatais, Altinópolis and Serrana. This aims to better understand the contribution of these abnormalities to MR in these regions, and thus characterizing the types and frequencies of chromosomal aberrations observed in order to compare them between APAEs. Patients suspected of chromosomal abnormalities were selected for the study. The criterion used for sample selection was the achievement of the karyotype of all patients affected by MR with major and/or minor structural abnormalities. Cytogenetic analysis was performed on cultures of peripheral blood lymphocytes, where the band G was used for staining. Twenty metaphases were analyzed per patient. Of the 505 individuals evaluated in three APAEs, a cytogenetic study was performed on 265 patients, and 61 chromosomal abnormalities were found (12.1% of the total and 23.0% of the selected karyotypes). In APAE of Batatais, karyotypes were performed on 174 of the 305 subjects studied, and we found 33 chromosomal abnormalities (10.8% of total). In Altinópolis, 54 karyotypes were performed out of the 107 subjects studied, and we observed 16 abnormal karyotypes (14.9% of total). In APAE Serrana, 37 karyotypes were performed out of the 93 subjects studied, and 12 chromosomal abnormalities (12.9% of total) were found. These results show that chromosomal abnormalities contribute significantly to the etiology of MR and that classical cytogenetics have important implications in medical practice for diagnosis of affected individuals as well as for genetic counseling of the families. Moreover, it is noted that in the APAE of Batatais, because of the smaller percentage of individuals affected by severe MR, 60.7% have a lower incidence of chromosomal abnormalities when compared to the APAEs of Altinópolis and Serrana which have frequencies of 87.8% and 83.9% of individuals with severe MR, respectively. This indicates that chromosomal abnormalities are more frequent in individuals affected by severe MR.

<p>Despite major advances in our understanding of the biology of childhood acute myeloid leukemia (AML) and the development of new cytotoxic drugs, the prognosis of long-term survival is still only 60-65 %.</p><p>In the present research, we studied the pharmacokinetics of drugs used in the induction therapy of childhood AML and performed in vitro drug sensitivity testing of leukemic cells from children with AML.</p><p>The aims of the studies were to correlate the results of the analysis to biological and clinical parameters and to identify subgroups of AML with specific drug sensitivity profiles in order to better understand why treatment fails in some patients and how therapy may be improved.</p><p>Blood samples were analysed to study the pharmacokinetics of doxorubicin (n=41), etoposide (n=45) and 6-thioguanine (n=50). Doxorubicin plasma concentration and total body clearance were correlated to the effect of induction therapy, and doxorubicin plasma concentration was an independent factor for complete remission, both in univariate and multivariate analysis including sex, age, and white blood cell count at diagnosis. For etoposide and 6-thioguanine no correlation was found between pharmacokinetics and clinical effect. Children with Down syndrome (DS) tended to reach higher blood concentrations of etoposide and thioguanine nucleotides, indicating that dose reduction may be reasonable to reach the same drug exposure as in children without DS.</p><p>Leukemic cells from 201 children with newly diagnosed AML, 15 of whom had DS, were successfully analysed for in vitro drug sensitivity by the fluorometric microculture cytotoxicity assay (FMCA). We found that samples from children with DS were highly sensitive to most drugs used in AML treatment. In non-DS children, the t(9;11) samples were significantly more sensitive to cytarabine (p=0.03) and doxorubicin (p=0.035) than other samples. The findings might explain the very favorable outcome reported in children with DS and t(9;11)-positive AML. A specific drug resistance profile was found for several other genetic subgroups as well. A detailed study of MLL-rearranged leukemia showed that cellular drug sensitivity is correlated both to partner genes and cell lineage, findings that support the strategy of contemporary protocols to include high-dose cytarabine in the treatment of patients with MLL-rearrangement, both in AML and acute lymphoblastic leukemia (ALL).</p><p>Our results indicate that drug resistance and pharmacokinetic studies may yield important information regarding drug response in different sub-groups of childhood AML, helping us to optimize future chemotherapy in childhood AML.</p>

Despite major advances in our understanding of the biology of childhood acute myeloid leukemia (AML) and the development of new cytotoxic drugs, the prognosis of long-term survival is still only 60-65 %. In the present research, we studied the pharmacokinetics of drugs used in the induction therapy of childhood AML and performed in vitro drug sensitivity testing of leukemic cells from children with AML. The aims of the studies were to correlate the results of the analysis to biological and clinical parameters and to identify subgroups of AML with specific drug sensitivity profiles in order to better understand why treatment fails in some patients and how therapy may be improved. Blood samples were analysed to study the pharmacokinetics of doxorubicin (n=41), etoposide (n=45) and 6-thioguanine (n=50). Doxorubicin plasma concentration and total body clearance were correlated to the effect of induction therapy, and doxorubicin plasma concentration was an independent factor for complete remission, both in univariate and multivariate analysis including sex, age, and white blood cell count at diagnosis. For etoposide and 6-thioguanine no correlation was found between pharmacokinetics and clinical effect. Children with Down syndrome (DS) tended to reach higher blood concentrations of etoposide and thioguanine nucleotides, indicating that dose reduction may be reasonable to reach the same drug exposure as in children without DS. Leukemic cells from 201 children with newly diagnosed AML, 15 of whom had DS, were successfully analysed for in vitro drug sensitivity by the fluorometric microculture cytotoxicity assay (FMCA). We found that samples from children with DS were highly sensitive to most drugs used in AML treatment. In non-DS children, the t(9;11) samples were significantly more sensitive to cytarabine (p=0.03) and doxorubicin (p=0.035) than other samples. The findings might explain the very favorable outcome reported in children with DS and t(9;11)-positive AML. A specific drug resistance profile was found for several other genetic subgroups as well. A detailed study of MLL-rearranged leukemia showed that cellular drug sensitivity is correlated both to partner genes and cell lineage, findings that support the strategy of contemporary protocols to include high-dose cytarabine in the treatment of patients with MLL-rearrangement, both in AML and acute lymphoblastic leukemia (ALL). Our results indicate that drug resistance and pharmacokinetic studies may yield important information regarding drug response in different sub-groups of childhood AML, helping us to optimize future chemotherapy in childhood AML.

Orientador: Agnes Cristina Fett Conte / Banca: Cleide Largman Borovik / Banca: Cláudia Regina Bonini Domingos / Resumo: Síndromes Mielodisplásicas (SMD) compreendem um conjunto heterogêneo de doenças hematopoéticas caracterizadas por hematopoese ineficaz, que geralmente apresentam citopenias no sangue periférico, medula óssea hipercelular, diferenciação celular displásica e propensão ao desenvolvimento de leucemia mielóide aguda. São classificadas em oito tipos e a incidência anual é estimada entre dois e 12 casos por 100.000 pessoas da população em geral e em até 50 casos por 100.000 indivíduos com idades superiores a 60 anos. A análise cromossômica das células da medula óssea dos doentes ao diagnóstico detecta alterações diretamente relacionadas com o prognóstico em aproximadamente 50% dos casos. Alguns genes também foram relacionados à etiologia e prognóstico das mielodisplasias. O gene FOXO3, um supressor de tumor, embora não estudado anteriormente em SMD, é um dos genes que mais se expressam no tecido hematopoético normal. Alterações neste gene poderiam resultar em hematopoese anormal, pois já foram relacionadas a outros tipos de câncer, com mutações descritas no éxon 1. O objetivo deste trabalho foi estudar células da medula óssea de doentes com SMD de qualquer tipo, ao diagnóstico, para investigar a presença de alterações cromossômicas e de mutações no éxon 1 do FOXO3. A análise citogenética foi realizada em metáfases submetidas ao bandamento GTG, obtidas de culturas de curta duração de células da medula, sem estimulação mitogênica. Para a análise molecular foi extraído o DNA, realizada a amplificação gênica pela Reação em Cadeia da Polimerase e realizado o sequenciamento direto do éxon 1. Entre os 25 casos analisados, três (12%) apresentaram alterações cromossômicas clonais isoladas: deleção intersticial do braço longo do cromossomo 5; monossomia do cromossomo 21 e monossomia do cromossomo 22. Todas puderam ser relacionadas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Myelodysplastic syndrome (MDS) constitute a heterogeneous group of hematopoietic diseases characterized by ineffective hematopoiesis usually with peripheral blood cytopenia, hypercellular bone marrow, dysplastic differentiation and a tendency to evolve to acute myeloid leukemia. They are classified in eight categories by the World Health Organization. The annual incidence is estimated at between two and 12 cases per 100,000 individuals in the general population and up to 50 cases per 100,000 of over 60-year olds. A chromosomal analysis of bone marrow cells at diagnosis identifies changes directly related to prognosis in approximately 50% of cases. Additionally, some genes are also associated to the etiology and prognosis of myelodysplasia. Although not previously studied in respect to MDS, a tumor suppressor, FOXO3, is one of the most commonly expressed genes in normal hematopoietic tissue. Changes in this gene could therefore result in abnormal hematopoiesis, as mutations described in exon 1 have already been associated with other types of cancer. The aim of this study was to investigate chromosomal alterations and mutations in exon 1 of FOXO3 in bone marrow cells from patients diagnosed with any type of MDS. Cytogenetic analysis was performed on metaphases submitted to GTG banding, obtained from short-term cultures of bone marrow cells without mitogenic stimulation. To evaluate mutations in the FOXO3 gene, DNA was extracted from the bone marrow, gene amplification was achieved by polymerase chain reaction and direct sequencing was performed. Of the 25 cases analyzed, three (12%) showed clonal chromosomal abnormalities in isolation characterized as the interstitial deletion of the long arm of chromosome 5, monosomy 21 and monosomy 22. All were correlated to the diagnosis and/or prognosis of patients. No mutations were detected in exon 1, but the 159C>T polymorphism was detected... (Complete abstract click electronic access below) / Mestre

A SMD primária hipocelular ocorre com uma frequência de 10-20% dos casos de SMD no adulto, no entanto, é o subtipo mais frequente na infância. O diagnóstico da SMD primária hipocelular é bastante difícil, pois devido à ausência de células na medula óssea esta pode ser confundida com a LMA hipocelular ou AA. O diagnóstico diferencial entre estas entidades hematológicas é de extrema importância devido a maior agressividade da LMA e a possibilidade de evolução da SMD para LMA. Além disso, SMD e AA são indicadas para o TCTH, entretanto, o regime de condicionamento pré-transplante é específico para cada doença. A combinação entre a análise morfológica, realizada através do mielograma e biópsia de medula óssea, e análise citogenética tem desempenhado um papel fundamental no reconhecimento da SMD primária hipocelular. Entretanto, estudos têm sido realizados para tentar melhorar o diagnóstico da doença levando em consideração as características biológicas da SMD como a presença de apoptose. Sendo assim, este estudo teve como objetivo caracterizar o padrão cromossômico da SMD primária hipocelular e correlacionar com aspectos celulares e clínicos. Foram analisados citogeneticamente 86 casos de SMD primária hipocelular, 74 AR, 10 com AREB e 2 com AREB-t. Dentre os pacientes com AR 50% apresentaram cariótipo anormal e todos os pacientes com AREB e AREB-t apresentaram cariótipo anormal. A alteração cromossômica mais frequente foi a del(17p), seguida de alterações envolvendo o cromossomo 7. Nossos resultados sugerem que o padrão cromossômico em SMD primária hipocelular é caracterizado principalmente por perdas parciais e completas de cromossomos (deleções e monossomias). A análise citogenética auxiliou no diagnóstico dos casos com suspeita de SMD primária hipocelular e foi uma importante ferramenta para a escolha do tratamento. O IPSS mostrou ser um bom sistema de escala prognostica para este grupo de pacientes. Alterações envolvendo o cromossomo 17 estiveram associados com o subtipo AR e características displásicas envolvendo o setor granulocítico, no entanto, a del(17p) também pôde ser observada no subtipo AREB. Para análise de apoptose foram utilizadas 42 amostras de pacientes com SMD, 23 com SMD hipocelular, 8 com SMD normocelular e 11 com SMD hipercelular. O índice de apoptose total nos casos de SMD primária hipocelular apresentou uma média de 9,5%, enquanto os pacientes com SMD primária normocelular e hipercelular apresentaram uma média de 12% e 14,1%, respectivamente. Pela análise de linhagens específicas as células já comprometidas com o programa de diferenciação celular parecem ser o principal alvo do programa de apoptose. Apesar dos pacientes com SMD primária hipocelular apresentarem índice de apoptose total mais elevado que os controles eles foram sempre inferiores aos apresentados pela SMD primária normocelular e hipercelular, com exceção dos eritroblastos que foram maiores nos casos de SMD primária hipocelular. O índice de apoptose total foi maior nos estágios iniciais da doença independentemente da celularidade da medula óssea. Os pacientes com del (11q) e del (17p) estiveram associados com a diminuição do índice de apoptose total. Nossos resultados sugerem que a hipocelularidade da medula óssea não é causada pelo processo de apoptose e sim provavelmente por algum defeito no programa de proliferação celular. / Hypocellular primary MDS occurs in a frequency of 10-20% of the adults MDS cases, however it is the most frequent subtype in childhood. Diagnosis of hypocellular primary MDS is very difficult, because the small number of cells in bone marrow and it can be confused with hypocellular AML or AA. The differential diagnosis between these hematologic entities is extremely important because of AML is more aggressive and the possibility of MDS evolve to AML. Besides, MDS and AA are indicated to HSCT, however, conditioning regimens before the transplantation is specific for each disease. The combination between morphologic analysis, carried out through mielogram and bone marrow biopsy, and cytogenetic analysis have been performed a fundamental role on the recognition of hypocellular primary MDS. However, studies have been carried out to try improving the MDS diagnosis considering the biological characteristics as the presence of apoptosis. Thus, the aim of this study was characterize the chromosomal pattern of hypocellular primary MDS and correlate with cellular and clinic aspects. It was analyzed 86 cases of hypocellular primary MDS, 74 RA, 10 RAEB and 2 RAEB-t. Patients with RA presented 50% of abnormal karyotype and all patients with RAEB presented abnormal karyotype as well as RAEB-t patients. The most frequent chromosomal alterations in this study was del(17p) followed by alterations involving chromosome 7. Our results suggest that chromosomal pattern in hypocellular primary MDS is characterized mainly by partial and complete loss of chromosomes (deletion and monosomy). The cytogenetic analysis aided in diagnosis of cases with suspicion of hypocellular primary MDS and it was an important tool for treatment choice. IPSS showed to be a good prognostic scoring system for this group of patients. Alterations involving chromosome 17 were associated with RA subtype and dysplastic characteristics involving granulocytic setor, however, we could see del(17p) in RAEB patients. For apoptosis analysis were used 42 samples of MDS patients, 23 with primary hypocellular MDS, 8 with primary normocelular MDS and 11 with primary hipercelular MDS. The total apoptosis index in cases of hypocellular primary MDS presented a average of 9,5%, whereas patients with primary normocelular MDS and primary hipercelular MDS presented an average of 12% and 14,1%, respectively. For the analysis of specific lineage cells already commited with cellular proliferation program appears to be the main target of apoptosis program. Despite of patients with primary hypocellular MDS presented total apoptosis index more raised than controls they were always lower than primary normocelular MDS and primary hipercelular MDS, except for eritroblasts that were higher in primary hypocellular. The total apoptosis index was higher in initial stage of the disease independently of the bone marrow cellularity. Patients with del(11q) and del(17p) were associated with decreasing of total apoptosis index. Our results suggest that the hypocellularity of bone marrow is not caused by apoptosis process, but probably by probably some defect in cellular proliferation program.

A SMD primária hipocelular ocorre com uma frequência de 10-20% dos casos de SMD no adulto, no entanto, é o subtipo mais frequente na infância. O diagnóstico da SMD primária hipocelular é bastante difícil, pois devido à ausência de células na medula óssea esta pode ser confundida com a LMA hipocelular ou AA. O diagnóstico diferencial entre estas entidades hematológicas é de extrema importância devido a maior agressividade da LMA e a possibilidade de evolução da SMD para LMA. Além disso, SMD e AA são indicadas para o TCTH, entretanto, o regime de condicionamento pré-transplante é específico para cada doença. A combinação entre a análise morfológica, realizada através do mielograma e biópsia de medula óssea, e análise citogenética tem desempenhado um papel fundamental no reconhecimento da SMD primária hipocelular. Entretanto, estudos têm sido realizados para tentar melhorar o diagnóstico da doença levando em consideração as características biológicas da SMD como a presença de apoptose. Sendo assim, este estudo teve como objetivo caracterizar o padrão cromossômico da SMD primária hipocelular e correlacionar com aspectos celulares e clínicos. Foram analisados citogeneticamente 86 casos de SMD primária hipocelular, 74 AR, 10 com AREB e 2 com AREB-t. Dentre os pacientes com AR 50% apresentaram cariótipo anormal e todos os pacientes com AREB e AREB-t apresentaram cariótipo anormal. A alteração cromossômica mais frequente foi a del(17p), seguida de alterações envolvendo o cromossomo 7. Nossos resultados sugerem que o padrão cromossômico em SMD primária hipocelular é caracterizado principalmente por perdas parciais e completas de cromossomos (deleções e monossomias). A análise citogenética auxiliou no diagnóstico dos casos com suspeita de SMD primária hipocelular e foi uma importante ferramenta para a escolha do tratamento. O IPSS mostrou ser um bom sistema de escala prognostica para este grupo de pacientes. Alterações envolvendo o cromossomo 17 estiveram associados com o subtipo AR e características displásicas envolvendo o setor granulocítico, no entanto, a del(17p) também pôde ser observada no subtipo AREB. Para análise de apoptose foram utilizadas 42 amostras de pacientes com SMD, 23 com SMD hipocelular, 8 com SMD normocelular e 11 com SMD hipercelular. O índice de apoptose total nos casos de SMD primária hipocelular apresentou uma média de 9,5%, enquanto os pacientes com SMD primária normocelular e hipercelular apresentaram uma média de 12% e 14,1%, respectivamente. Pela análise de linhagens específicas as células já comprometidas com o programa de diferenciação celular parecem ser o principal alvo do programa de apoptose. Apesar dos pacientes com SMD primária hipocelular apresentarem índice de apoptose total mais elevado que os controles eles foram sempre inferiores aos apresentados pela SMD primária normocelular e hipercelular, com exceção dos eritroblastos que foram maiores nos casos de SMD primária hipocelular. O índice de apoptose total foi maior nos estágios iniciais da doença independentemente da celularidade da medula óssea. Os pacientes com del (11q) e del (17p) estiveram associados com a diminuição do índice de apoptose total. Nossos resultados sugerem que a hipocelularidade da medula óssea não é causada pelo processo de apoptose e sim provavelmente por algum defeito no programa de proliferação celular. / Hypocellular primary MDS occurs in a frequency of 10-20% of the adults MDS cases, however it is the most frequent subtype in childhood. Diagnosis of hypocellular primary MDS is very difficult, because the small number of cells in bone marrow and it can be confused with hypocellular AML or AA. The differential diagnosis between these hematologic entities is extremely important because of AML is more aggressive and the possibility of MDS evolve to AML. Besides, MDS and AA are indicated to HSCT, however, conditioning regimens before the transplantation is specific for each disease. The combination between morphologic analysis, carried out through mielogram and bone marrow biopsy, and cytogenetic analysis have been performed a fundamental role on the recognition of hypocellular primary MDS. However, studies have been carried out to try improving the MDS diagnosis considering the biological characteristics as the presence of apoptosis. Thus, the aim of this study was characterize the chromosomal pattern of hypocellular primary MDS and correlate with cellular and clinic aspects. It was analyzed 86 cases of hypocellular primary MDS, 74 RA, 10 RAEB and 2 RAEB-t. Patients with RA presented 50% of abnormal karyotype and all patients with RAEB presented abnormal karyotype as well as RAEB-t patients. The most frequent chromosomal alterations in this study was del(17p) followed by alterations involving chromosome 7. Our results suggest that chromosomal pattern in hypocellular primary MDS is characterized mainly by partial and complete loss of chromosomes (deletion and monosomy). The cytogenetic analysis aided in diagnosis of cases with suspicion of hypocellular primary MDS and it was an important tool for treatment choice. IPSS showed to be a good prognostic scoring system for this group of patients. Alterations involving chromosome 17 were associated with RA subtype and dysplastic characteristics involving granulocytic setor, however, we could see del(17p) in RAEB patients. For apoptosis analysis were used 42 samples of MDS patients, 23 with primary hypocellular MDS, 8 with primary normocelular MDS and 11 with primary hipercelular MDS. The total apoptosis index in cases of hypocellular primary MDS presented a average of 9,5%, whereas patients with primary normocelular MDS and primary hipercelular MDS presented an average of 12% and 14,1%, respectively. For the analysis of specific lineage cells already commited with cellular proliferation program appears to be the main target of apoptosis program. Despite of patients with primary hypocellular MDS presented total apoptosis index more raised than controls they were always lower than primary normocelular MDS and primary hipercelular MDS, except for eritroblasts that were higher in primary hypocellular. The total apoptosis index was higher in initial stage of the disease independently of the bone marrow cellularity. Patients with del(11q) and del(17p) were associated with decreasing of total apoptosis index. Our results suggest that the hypocellularity of bone marrow is not caused by apoptosis process, but probably by probably some defect in cellular proliferation program.