RESUMO
In order to contribute to the knowledge of type and frequency of chromosome abnormalities in early pregnancy losses, we analyzed the cytogenetic results from a large series of first trimester miscarriages, using a diagnostic approach with a high success rate and no maternal contamination. A total of 1,119 consecutive chorionic villi samples were obtained before evacuation, and karyotypes were prepared after short-term culture (STC). In 603 samples, a long-term culture (LTC) was also performed. The overall and individual frequencies of the different types of chromosome abnormalities were established, including placental mosaicisms, and their relationship with maternal age and gestational weeks was assessed. An abnormal karyotype was detected in 70.3% of the samples. Single autosomal trisomy was the most frequent abnormality (64.6% of the abnormal cases), followed by triploidy (13.1%) and monosomy X (10.4%). Chromosome rearrangements were found in 5.2%, combined abnormalities in 8.9%, and placental mosaicism in 3.5% of the cases with STC and LTC performed. Individual trisomies behaved differently with respect to maternal age and intrauterine survival. Due to the combination of STC and LTC, our study offers reliable information on the incidence and type of chromosome abnormalities and placental mosaicism in miscarriages and contributes to define the cytogenetic implication in their etiology.
Assuntos
Aborto Espontâneo/genética , Vilosidades Coriônicas/metabolismo , Aberrações Cromossômicas , Cariótipo , Cariotipagem/métodos , Primeiro Trimestre da Gravidez/genética , Feminino , Rearranjo Gênico/genética , Idade Gestacional , Humanos , Idade Materna , Mosaicismo , Placenta/patologia , Ploidias , Gravidez , Cromossomos Sexuais/genética , Trissomia/genéticaRESUMO
The patient was referred for prenatal diagnosis due to the sonographic finding of a polymalformed male fetus, and an amniocentesis was performed before termination of pregnancy. The pathological study of the placenta did not show morphological alterations. In her next pregnancy, sonographic examination disclosed a missed abortion with a visible embryo, and a chorionic villi sample was obtained for cytogenetic analysis before evacuation. Macroscopic examination of the villi sample did not reveal molar vesicular appearance. QF-PCR and cytogenetic analyses were performed on amniotic fluid (first pregnancy) and chorionic villi samples (second pregnancy). A 69,XXY and 92,XXXY karyotype was found, respectively. QF-PCR results disclosed 2 maternal and 1 paternal alleles in the first pregnancy (digynic triploidy), and double maternal and double paternal contribution to the tetraploid pregnancy. Among the few reported cases of 92,XXXY tetraploidy, those associated with partial moles show a PPPM genotype (3 paternal and 1 maternal alleles), and the only case with a PPMM genotype was found in a spontaneously aborted fetus similar to our case. We are not aware of other cases with combination of a digynic triploid pregnancy and a tetraploid pregnancy with a PPMM contribution. Our case adds evidence to the influence of the balance between paternal and maternal genomic doses on the phenotype.
Assuntos
Aborto Espontâneo/genética , Feto/anormalidades , Tetraploidia , Triploidia , Alelos , Amniocentese , Amostra da Vilosidade Coriônica , Feminino , Humanos , Mola Hidatiforme/genética , Masculino , Herança Materna/genética , Repetições de Microssatélites , Herança Paterna/genética , GravidezRESUMO
OBJECTIVE: To analyze karyotype of Turner's syndrome (TS) patients in two tissues of different lineage, and to correlate them with phenotype. STUDY DESIGN: An observational study was designed at the Gynaecological Endocrinology Unit of Hospital Clinic in Barcelona. Patients diagnosed with TS by blood karyotype were included, between 20 and 50 years of age. A new 50-cell count blood karyotype and a urethral cell karyotype from urine samples were performed. Data on some TS-related comorbidities were collected. RESULTS: Twenty-seven TS patients were included. Urine cultures of 12 patients were contaminated by microorganisms. With 50-cell count blood karyotype, three cryptic mosaicisms were found. Six patients with mosaicism in blood karyotype showed pure monosomy in urine karyotype. Correlations exist between blood karyotype and phenotype where spontaneous menarche, height, dysmorphology, congenital malformations and hypothyroidism are concerned, whereas they did not appear in urine analysis. CONCLUSIONS: Karyotyping T-lymphocytes in blood samples is the gold standard technique. 50-cell count may be considered if TS or ovarian failure is suspected, in order to detect cryptic mosaicisms. Urethral cell culture from urine samples presents technical difficulties and some limitations, due to the easier lost of abnormal X-chromosome. A partial correlation between blood karyotype and phenotype exists.
Assuntos
Cariotipagem/métodos , Síndrome de Turner/genética , Adulto , Células Epiteliais/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Linfócitos T/patologia , Síndrome de Turner/patologia , Síndrome de Turner/urina , Adulto JovemRESUMO
La presencia en un paciente de un fenotipo clínico característico es la indicación usual para el estudio posnatal de posible disomía uniparental (DUP). En diagnóstico prenatal la situación es más compleja, ya que la información clínica es mucho más limitada, y los estudios de DUP se plantean únicamente en determinadas situaciones de riesgo, relacionadas con la presencia de alteraciones cromosómicas numéricas o estructurales en el conjunto feto/placenta o en los progenitores, o con la detección ecográfica de algún tipo de anomalías del desarrollo fetal o de malformaciones fetales. El objetivo del presente trabajo es presentar la experiencia de nuestro centro en diagnóstico prenatal de DUP. Métodos. Desde 1998 se han realizado en nuestro centro 165 estudios prenatales de DUP de los cromosomas 6 (n = 1), 7 (n = 24), 11 (n = 4), 14 (n = 81) y 15 (n = 55) correspondientes a 154 gestaciones; en 11 de ellas se han estudiado 2 cromosomas a la vez. El estudio molecular se ha realizado mediante el análisis de segregación de marcadores microsatélites polimórficos distribuidos a lo largo del cromosoma implicado. Resultados. Se han detectado 2 casos de DUP materna, uno del cromosoma 7 y otro del 15, ambos debidos a mosaicos confinados a placenta de la trisomía correspondiente. Se ha valorado la tasa de detección de DUP con respecto al tipo de indicación. Conclusiones. Aunque la DUP es un fenómeno poco frecuente, la gravedad de sus consecuencias clínicas hace absolutamente recomendable su estudio prenatal en las situaciones de riesgo definidas por las normativas internacionales(AU)
Introduction. The usual indication for postnatal uniparental disomy (UPD) testing is a characteristic clinical phenotype present in a patient. The situation in prenatal diagnosis is more complex because the clinical information is much more limited, and the UPD tests are only considered in certain risk situations related to the presence of numerical or structural chromosomal abnormalities in the foetal/placental unit and/or in the parents, or with the ultrasound detection of foetal developmental anomalies or foetal malformations. The objective of this study is to present the experience of our centre in UPD prenatal testing. Methods. A total of 165 UPD prenatal analyses were performed out in our centre since 1998, involving chromosomes 6 (n = 1), 7 (n = 24), 11 (n = 4), 14 (n = 81), and 15 (n = 55), corresponding to 154 gestations; 2 chromosomes have been studied at the same time in 11 of them. Molecular studies were carried out by segregation analysis of polymorphic microsatellite markers distributed along the involved chromosomes. Results. Two maternal UPD cases of chromosomes 7 and 15 were detected, both of them due to confined placental mosaicism of the corresponding trisomy. The detection rate was evaluated with regard to the different indications. Conclusions. Although UPD is a rare phenomenon, the severity of its clinical consequences makes its prenatal study absolutely advisable in the risk situations defined in the international guidelines(AU)
Assuntos
Humanos , Masculino , Feminino , Diagnóstico Pré-Natal/instrumentação , Diagnóstico Pré-Natal/métodos , Diagnóstico Pré-Natal , Dissomia Uniparental/diagnóstico , Dissomia Uniparental/genética , Mosaicismo/embriologia , Mosaicismo/estatística & dados numéricos , Análise Citogenética , Dissomia Uniparental/citologia , Dissomia Uniparental/fisiopatologia , Aberrações Cromossômicas , Cromossomos Humanos Par 6/genética , Cromossomos Humanos Par 7/genética , Cromossomos Humanos Par 15/genéticaRESUMO
Congenital heart defects (CHD) represent the most common birth defects, so they are not a rare finding when performing routine ultrasound examinations during pregnancy. Once chromosome abnormalities have been excluded in a fetus with a CHD, chromosome 22q11.2 deletion is usually investigated by FISH, as it is the most frequent microdeletion syndrome and is generally associated with cardiac malformations. If 22q11.2 microdeletion is ruled out, the etiology of the CHD remains generally unexplained, making familial genetic counseling difficult. To evaluate the usefulness of Multiplex Ligation-dependent Probe Amplification (MLPA) kits designed for the study of 22q11.2 and other genomic regions previously associated with syndromic CHD, we performed MLPA in 55 pregnancies with fetuses presenting CHD, normal karyotype and negative FISH results for 22q11.2 microdeletion, which constitutes the largest prenatal series reported. Definitive MLPA results were obtained in 50 pregnancies, and in this setting such MLPA kits did not detect any imbalance. On the other hand, to compare FISH and MLPA techniques for the study of 22q11.2 microdeletions, we performed MLPA in 4 pregnancies known to have 22q11.2 deletions (by FISH). All four 22q11.2 microdeletions were also detected by MLPA, which corroborates that it is a reliable technique for the diagnosis and characterization of 22q11.2 deletions. Finally, we evaluated the possibility of replacing conventional FISH by MLPA for the prenatal diagnosis of CHD, comparing the diagnostic potential, results delivery times, repetition and failure rates and cost of both techniques, and concluded that FISH should still be the technique of choice for the prenatal diagnosis of fetuses with CHD.
Assuntos
Cardiopatias Congênitas/genética , Reação em Cadeia da Polimerase Multiplex/métodos , Diagnóstico Pré-Natal/métodos , Deleção Cromossômica , Cromossomos Humanos Par 22 , Feminino , Cardiopatias Congênitas/diagnóstico por imagem , Humanos , Gravidez , Estudos Prospectivos , UltrassonografiaRESUMO
The deletion of the long arm of chromosome 18 causes a contiguous gene deletion syndrome with a highly variable phenotype, usually related to the extent of the deleted region. The most commonly reported clinical features include: decreased growth, microcephaly, facial abnormalities, hypotonia, developmental delay, intellectual disability, congenital aural atresia with hearing impairment and limb anomalies. Here we report on a familial terminal deletion of 18q23 region transmitted from a mother to two daughters, resulting in a remarkable phenotypic variability. The deletion was first detected by conventional cytogenetic analysis in one daughter and subsequently characterized using fluorescence in situ hybridization (FISH) and array-CGH. FISH analysis using subtelomeric 18p and 18q probes confirmed the 18qter deletion in the three patients, and FISH with a whole chromosome painting probe specific for chromosome 18 excluded rearrangements with other chromosomes. Array-CGH analysis allowed us to precisely define the extent of the deletion, which spans 4.8 Mb from 71,236,891 to 76,093,303 genomic positions and includes GALR1 and MBP genes, among others. High-resolution analysis of the deletion, besides a detailed clinical assessment, has provided important data for phenotype-genotype correlation and genetic counseling in this family. Furthermore, this study adds valuable information for phenotype-genotype correlation in 18q- syndrome and might facilitate future search for candidate genes involved in each phenotypic trait.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 18 , Hormônio do Crescimento/deficiência , Estatura/genética , Criança , Hibridização Genômica Comparativa , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , FenótipoRESUMO
OBJECTIVE: To evaluate the usefulness of subtelomeric multiplex ligation-dependent probe amplification (MLPA) in both the detection of subtelomeric rearrangements in fetuses with ultrasound abnormalities and normal karyotype, and the characterization of cytogenetically detectable rearrangements. METHOD: We studied by subtelomeric MLPA 229 pregnancies with ultrasound findings and normal karyotype (Group 1) and five pregnancies with a cytogenetically visible but not microscopically characterizable rearrangement (Group 2). The detected imbalances were confirmed by fluorescence in situ hybridization (FISH) and parents were also studied. RESULTS: In Group 1, two clinically relevant subtelomeric imbalances (14qter deletion and 20pter deletion) and one subtelomeric imbalance of uncertain significance (X/Ypter duplication) were diagnosed, showing a detection rate of cryptic subtelomeric imbalances in these pregnancies of 1.3%. However, only 14qter deletion seems to be clearly associated with the observed prenatal findings. In Group 2, MLPA contributed to the precise description of the chromosome abnormalities. CONCLUSION: The low detection rate of subtelomeric imbalances and the poor genotype-phenotype correlations in pregnancies with ultrasound abnormalities and normal karyotype suggest that subtelomeric MLPA is not a crucial tool in the prenatal diagnosis of these cases. However, our work provides evidence that MLPA is very useful for the characterization of unbalanced karyotypes. Copyright © 2010 John Wiley & Sons, Ltd.
Assuntos
Reação em Cadeia da Ligase/métodos , Diagnóstico Pré-Natal/métodos , Telômero/genética , Aberrações Cromossômicas , Anormalidades Congênitas/diagnóstico por imagem , Anormalidades Congênitas/genética , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino , Valor Preditivo dos Testes , Gravidez , Sensibilidade e Especificidade , UltrassonografiaRESUMO
The identification of an unexpected structural chromosome rearrangement at prenatal diagnosis can be problematic and raises unique genetic counseling issues. We describe two consecutive prenatal cases within a family with an inherited unbalanced (Y;12) translocation and discuss the genotype-phenotype correlation. The first fetus presented with 12qter monosomy and pseudoautosomal region 2 trisomy, while the second fetus had the alternative unbalanced state. Although the first fetus had a structural heart defect, such small imbalances might not give sonographic findings, making their prenatal diagnosis difficult. However, congenital abnormalities are expected in both unbalanced forms of the translocation, including mental retardation, which could be explained by the gene dosage variation of P2RX2. To our knowledge, these are the first published cases reporting this subtype of (Y;12) translocation, in both balanced and unbalanced states.
Assuntos
Cromossomos Humanos Par 12/genética , Cromossomos Humanos Y/genética , Padrões de Herança/genética , Diagnóstico Pré-Natal , Translocação Genética , Feminino , Feto/anormalidades , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , GravidezAssuntos
Proteínas Sanguíneas/genética , Cromossomos Humanos Par 3 , Deficiência de Proteína S/genética , Proteína S/genética , Translocação Genética , Trombose Venosa/genética , Acenocumarol/uso terapêutico , Adulto , Anticoagulantes/uso terapêutico , Proteínas Sanguíneas/análise , Análise Mutacional de DNA , Predisposição Genética para Doença , Humanos , Hibridização in Situ Fluorescente , Masculino , Proteína S/análise , Deficiência de Proteína S/complicações , Deficiência de Proteína S/tratamento farmacológico , Trombose Venosa/tratamento farmacológicoRESUMO
Male individuals with a 46,XX karyotype have been designated as XX males. In 80% of the cases, the presence of Yp sequences, including the male sex-determining gene, SRY, has been demonstrated by molecular and/or fluorescence in situ hybridization (FISH) analyses. In most cases, Yp sequences are located on the short arm of the X chromosome, resulting from unequal recombination between Yp and Xp during paternal meiosis. Much less frequent in XX males is the localization of the SRY gene to an autosome. Here we report on the genetic investigation of an atypical XX male in which the SRY gene was located at the end of the long arm of chromosome 1. The patient, with a normal male phenotype, was referred for azoospermia. Conventional cytogenetic analysis showed a 46,XX karyotype. Molecular-cytogenetics (FISH) and molecular (PCR and MLPA) studies identified not only Yp-specific sequences located on the distal long arm of chromosome 1 but also the deletion of the subtelomeric 1qter region. A specific phenotype has been reported for a deletion of the 1qter region associated with mental retardation. The molecular investigation of the 1qter region showed that in our patient the microdeletion is more telomeric than in patients reported with mental retardation. To our knowledge, this is the first report of a XX male with the Yp region transferred to the terminal long arm of chromosome 1. This is also the first microdeletion of the subtelomeric 1qter region not associated with mental retardation.
Assuntos
Azoospermia/genética , Deleção Cromossômica , Cromossomos Humanos Par 1/genética , Disgenesia Gonadal 46 XX/genética , Proteína da Região Y Determinante do Sexo/genética , Adulto , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase/métodos , TelômeroRESUMO
OBJECTIVES: To report our experience over the past 10 years of chorionic villi sampling (CVS) prenatal diagnosis in a high-risk population for chromosomal anomalies, and to analyze, according to the results, the advantages and disadvantages of using quantitative fluorescence polymerase chain reaction (QF-PCR) in amniotic fluid with respect to a conventional semi-direct cytogenetic CVS method in a retrospective theoretical review. METHODS: We performed 3,868 cytogenetic analyses from CVS using a semi-direct culture method in a selected high-risk population for chromosomal abnormalities and we compare our findings with the theoretical results obtained using QF-PCR on amniotic fluid. RESULTS: The rate of chromosomal anomalies detected with the semi-direct CVS cytogenetic study, excluding confined placental mosaicism (CPM), was 6.8%. 26.3% of all them would be missed by using QF-PCR only and among them, 21.4% of cases would represent a severe adverse obstetric outcome. CONCLUSIONS: We think that semi-direct CVS cytogenetic analysis in comparison with QF-PCR in amniotic fluid is similarly rapid, performed earlier and more complete, allowing the chromosomal diagnosis in the first trimester of gestation. We propose the use of QF-PCR as an additional method to semi-direct CVS analysis in order to avoid false-negative results, as a rapid alternative to long-term culture.
Assuntos
Amostra da Vilosidade Coriônica/métodos , Aberrações Cromossômicas , Aconselhamento Genético/métodos , Diagnóstico Pré-Natal/métodos , Adulto , Amostra da Vilosidade Coriônica/normas , Transtornos Cromossômicos/diagnóstico , Transtornos Cromossômicos/genética , Feminino , Aconselhamento Genético/normas , Humanos , Gravidez , Diagnóstico Pré-Natal/normas , Estudos RetrospectivosRESUMO
Conventional tissue culturing and karyotyping of spontaneous abortions has limitations such as culture failure, external contamination and selective growth of maternal cells. Molecular cytogenetic techniques such as FISH, QF-PCR, and CGH allow diagnosis on uncultured cells but are also limited as to the spectrum of cytogenetic abnormalities detected. We describe the cytogenetic findings in a series of 116 first trimester arrested pregnancies, obtained through chorionic villi sampling (CVS) and semi-direct analysis that avoids some of the long-culture pitfalls such as maternal contamination, and compare our results with those that would have been obtained theoretically using molecular cytogenetic techniques. Samples were obtained by transcervical CVS from women with a diagnosis of missed abortion, most of them referred for cytogenetic prenatal diagnosis. Cytogenetic analysis was performed using semi-direct technique. A karyotype was obtained in 103 cases. Eighty-two abnormal karyotypes were found (80%), including 12 triploidies, 10 monosomies, 61 trisomies, and 9 structural abnormalities; a double abnormality being present in 10 cases. Between 10% and 50% of our abnormal results would have been missed using the most common molecular cytogenetic techniques. Semi-direct analysis of CVS may still be considered as a comprehensive, reasonably rapid, cost-effective and reliable method for detecting the broadest spectrum of chromosome abnormalities in missed abortions.
Assuntos
Aborto Espontâneo , Vilosidades Coriônicas/embriologia , Aberrações Cromossômicas , Análise Citogenética , Aneuploidia , Amostra da Vilosidade Coriônica/métodos , Cromossomos Humanos Par 13 , Cromossomos Humanos Par 18 , Cromossomos Humanos Par 21 , Feminino , Humanos , Cariotipagem , Gravidez , Primeiro Trimestre da Gravidez , Diagnóstico Pré-Natal , Aberrações dos Cromossomos Sexuais , TrissomiaAssuntos
Aberrações Cromossômicas , Transtornos Cromossômicos/epidemiologia , Análise Citogenética , Adolescente , Adulto , Fatores Etários , Criança , Pré-Escolar , Transtornos Cromossômicos/diagnóstico , Transtornos Cromossômicos/genética , Feminino , Aconselhamento Genético , Genótipo , Humanos , Incidência , Lactente , Recém-Nascido , Cariotipagem , Masculino , Mutação , Fenótipo , Fatores Sexuais , Espanha/epidemiologia , TrissomiaRESUMO
No disponible
Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Análise Citogenética , Aberrações Cromossômicas/estatística & dados numéricos , Programas de Rastreamento , Espanha/epidemiologia , Cariotipagem/métodos , Aconselhamento GenéticoRESUMO
Supernumerary marker chromosomes (SMCs) have a reported frequency in the prenatal and newborn population ranging from 0.04% to 0.08% and about 37% of diagnosed SMCs are associated with an abnormal phenotype. Around 7.5% of them are derived from chromosome 22. SMCs(22) that result in tri- or tetrasomy of band 22q11.2 are associated with Cat-eye syndrome (CES), a syndrome of variable penetrance and affectation. CES-like phenotype has been also related to 22q11.2 interstitial duplications and der(22) syndrome. The 22q11.2 region, also involved in the velocardiofacial microdeletional syndrome, presents high susceptibility to chromosomal rearrangements due to the presence of low-copy repeats sequences (LCR22). Another region in the genome rich in LCR is 17p and five recurrent disorders have been mapped on the region 17p11-p13. Some chromosomal imbalances affecting the 17p13.3 subtelomeric region have been reported, related to cryptic unbalanced translocations and associated, in most cases, to mental retardation and dysmorphic features. We report on a healthy male carrier of a SMC that was identified as a +der(22)t(17;22)(p13.3;q11.2) consequence of an abnormal 3:1 segregation of the paternal t(17;22) and we have determined the approximate size of the trisomic regions, comparing the obtained results with other reported imbalances involving 22q11.2 and 17pter.
Assuntos
Cromossomos Humanos Par 17 , Cromossomos Humanos Par 22 , Telômero/genética , Trissomia , Adulto , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual/genética , MasculinoRESUMO
Mosaicism for structural aberrations is a rare event and the coexistence of a cell line with a duplication and another with a deletion of the same chromosome segment is even more infrequent. We report a boy with a 46,XY,del(7q)/46,XY,dup(7q) mosaicism. High-resolution cytogenetic analysis and fluorescent in situ hybridization (FISH) performed at birth showed a trisomy for region 7q21.1 to 7q31.3 in 90% of metaphases analyzed and monosomy for the same region in 10% of metaphases. At the age of 12 months, karyotype on peripheral blood and exfoliated urinary epithelial cells was 46,XY,dup(7)(q21.1q31.3) in all cells analyzed. The patient presented malformations and psychomotor retardation. His phenotype is compared with other previously case reports describing patients with an interstitial duplication of 7(q21 or q22 --> q31.3). Due to the absence of a normal cell line, we propose a post-zygotic origin of the abnormality during the first mitotic division and a progressive loss of the deleted cells during pre- and post-natal development by selective pressure. The patient described here emphasizes the possible existence of an undetectable cell line in patients previously diagnosed of pure partial 7q trisomy or monosomy to explain the great clinical variability between reported patients. We also describe the culture of urinary epithelial cells in order to perform cytogenetic analysis as a useful non-invasive method.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 7/genética , Duplicação Gênica , Mosaicismo , Transtornos Psicomotores/genética , Adulto , Braço/patologia , Células Cultivadas , Análise Citogenética , Células Epiteliais , Feminino , Mãos/patologia , Humanos , Hibridização in Situ Fluorescente , Recém-Nascido , Masculino , Transtornos Psicomotores/patologia , Crânio/patologia , Urina/citologiaRESUMO
We report an unusual case of a familial complex chromosome rearrangement (CCR), ascertained through prenatal diagnosis. The fetus carried an apparently balanced CCR with a recombinant 3-segment chromosome derived from two paternal reciprocal translocations involving both homologs of chromosome 14 and chromosomes 15 and 21, respectively. A probably normal phenotype was predicted and confirmed after birth. His older sister carried an unbalanced karyotype with partial trisomy 14 and partial monosomy 21, and displayed an apparently normal, paternally derived chromosome 14 that resulted from recombination between two derivative chromosomes. Fluorescent in situ hybridization (FISH) and molecular studies were essential for the characterization of the rearrangement. The "rebuilding," through recombination, of a chromosome involved in two different translocations in a progenitor, was demonstrated for the first time by molecular analysis. Our family is another good example of how balanced familial complex translocations are in a state of flux and can change from one generation to the next.
Assuntos
Cromossomos Humanos Par 14/genética , Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 21/genética , Translocação Genética , Saúde da Família , Feminino , Heterozigoto , Humanos , Hibridização in Situ Fluorescente , Lactente , Cariotipagem , Masculino , Modelos Genéticos , Recombinação GenéticaRESUMO
BACKGROUND: The Y chromosome gr/gr microdeletion eliminates two copies of the DAZ gene and several additional transcriptional units and has been associated as a risk factor for infertility. Our objective was to study the presence of the gr/gr deletion in ICSI candidates in our population and to determine whether the laboratory, clinical and ICSI outcome were different in the gr/gr deleted patients. METHODS: Two hundred and eighty-three ICSI candidates were studied. Semen analysis, serum FSH, LH, testosterone, inhibin B, karyotype and detection of sequence tagged sites in the Y chromosome were performed. RESULTS: gr/gr deletions were detected in 11 (5.07%) of 217 oligospermic and in one (1.52%) of 66 azoospermic consecutive ICSI candidates, but in none of 232 controls (P=0.002). The fertility rate was not different in the four patients of the gr/gr deleted group treated by ICSI (64.38%; 47/73) as compared to average results at our center (65.49%; 2393/3654). CONCLUSIONS: gr/gr deletions are a risk factor for spermatogenic failure at our population, but the prognosis of the four patients of the gr/gr deleted group treated by ICSI is not different from that of other ICSI patients.