1/130. Isolated tetrasomy 8 in minimally differentiated acute myeloid leukemia (AML-M0).tetrasomy 8 as a sole anomaly in hematological disorders is relatively rare. To the best of our knowledge, only 19 such cases have been described in the literature to date. Of them, acute myeloid leukemia (AML) in 13 (M1, one; M2, three; M4, one; M5, eight), acute lymphoblastic leukemia(ALL) in one, myelodysplastic syndrome(MDS) in 3, polycythemia vera(PV) and myelofibrosis(MF), one case each. Their median survival was 20 weeks. Here, we report the first case of a 29-year-old man with minimally differentiated AML (AML-M0) displaying a tetrasomy 8 clone. immunophenotyping showed positivity with CD33, CD34 and intracellular MPO, but all lymphoid markers tested were negative. Conventional cytogenetics of bone marrow cells showed 84.9% of metaphases with tetrasomy 8 in addition to 15.1% with normal diploidy. However, fluorescence in situ hybridization(FISH) using a centromeric probe specific for chromosome 8 revealed trisomy 8 in 14.2% of interphase nuclei besides tetrasomy 8 in 82.4%. The patient died four weeks after diagnosis without therapy. In conclusion, these findings suggest that tetrasomy 8 is associated with a heterogeneous group of myeloid disorders and heralds a bad prognosis. It may be a consequence of clonal evolution of trisomy 8.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/130. Analysis of the sex chromosome constitution of sperm in men with a 47, XYY mosaic karyotype by fluorescence in situ hybridization.OBJECTIVE: To determine the incidence of sex chromosome aneuploidy in the sperm of two men with a 47,XYY/46,XY karyotype. DESIGN: Case report. SETTING: infertility clinic in a teaching hospital. PATIENT(S): One patient with near normal semen parameters whose wife had a history of miscarriages and one patient with primary infertility and severe oligoasthenozoospermia. INTERVENTION(S): cytogenetic analysis of peripheral lymphocytes and three-color X/Y/18 fluorescence in situ hybridization analysis of sperm. MAIN OUTCOME MEASURE(S): Analysis of sex chromosome disomy and diploidy rates in sperm. RESULT(S): Both patients had a 47,XYY/46,XY karyotype. The hyperdiploidy rate of patient 1 was 19% and that of patient 2 was 90%. The incidence of disomy XY was significantly elevated in both patients compared with the controls (0.23% and 1.02%, respectively, versus 0.10%). The incidence of disomy YY (0.44% versus 0.10%) was increased only in patient 2, as was the incidence of disomy 18 (0.49% versus 0.09%) and the rate of diploidy (0.83% versus 0.13%). The rate of 24,XX sperm in both patients was not different from that in the controls. CONCLUSION(S): patients with a 47,XYY mosaic karyotype may be at risk of producing offspring with a hyperdiploid sex constitution. These patients should have their sperm investigated by fluorescence in situ hybridization to determine their particular risks before they undergo intracytoplasmic sperm injection.- - - - - - - - - - ranking = 6keywords = hybridization (Clic here for more details about this article) |
3/130. Sex chromosome aneuploidies in sperm of 47,XYY men.The sex chromosomal equipment in 26,675 sperm of 47,XYY males was analyzed. A total of 5.78% of the nuclei exhibited sex chromosome hyperhaploidy. Six studies have analyzed the sperm of 10 XYY patients and, although these studies indicated some degree of elimination of the extra y chromosome during spermatogenesis, a certain percentage of XYY germinal cells may also be able to achieve meiosis and produce sperm with gonosomal disomies. All these studies show an increased incidence of gonosomal aneuploidies in sperm, but there are significant discrepancies concerning the extent of these abnormalities. The global frequencies of sperm with an abnormal number of sex chromosomes ranged from 0.578 to 13.91%, depending on the patients. There are several explanations for these discrepancies: differences attributed to fluorescence in situ hybridization methodology, the use of dual or multicolor FISH, recruitment, interindividual variations, and intraindividual variations. This study reports an additional series obtained from another XYY individual and compares and discusses the data on gonosomal hyperhaploidies in sperm of 47 XYY males using in situ hybridization analyses.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
4/130. tetrasomy 9p due to an intrachromosomal triplication of 9p13-p22.To date, approximately 30 patients have been described with a tetrasomy 9p, all being caused by the presence of an isochromosome 9p. We now report on a 3-year-old boy with a de novo intrachromosomal triplication of 9p13-p22, resulting in partial tetrasomy 9p. We compared his phenotype with cases of tetrasomy 9p caused by the presence of an extra isochromosome 9p. He has facial anomalies similar to those of cases of tetrasomy 9p, central nervous system abnormalities, and severe psychomotor retardation but no other major congenital anomalies. fluorescence in situ hybridization with region-specific probes showed that the middle repeat of the triplicated part is inverted. Microsatellite analysis demonstrated an involvement of both paternal chromosome 9 homologues in the triplication. This is compatible with either unequal crossing over of three of the four chromatids in paternal meiosis I or with a double crossing over in meiosis I and II (or an early mitotic division).- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/130. Chromosome duplications and deletions and their mechanisms of origin.Duplications and deletions of the same gene loci or chromosome regions are known to produce different clinical manifestations and are significant factors in human morbidity and mortality. Extensive cytogenetic and molecular cytogenetic studies with cosmid and YAC probes in two patients with unique mosaicism for reciprocal duplication-deletion allowed us to further understand the origin of these abnormalities. The first patient's mosaic karyotype was 46,XX, inv dup(11) (q23q13)/46,XX,del(11)(q13q23). The second patient had a 46,XY,dup(7)(p11.2p13)/46,XY,del(7)(p11.2p13)/46,XY karyotype. fluorescence in situ hybridization studies on the first patient placed the two breakpoints near the folate-sensitive fragile sites FRA11A and FRA11B. The presence of repeated sequences responsible for these fragile sites may have been involved in the patient's duplication-deletion. Our investigation leads us to conclude that, in addition to known mechanisms (such as unequal crossovers between homologs, unequal sister chromatid exchanges, excision of intrachromatid loops, and meiotic recombination within a single chromatid), duplication-deletion can also arise by the formation of an overlying loop followed by an uneven crossover at the level of the dna strand.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/130. Translocation (15;17)(q22;q21) as a secondary chromosomal abnormality in a case of acute monoblastic leukemia with tetrasomy 8.We describe a case of acute monoblastic leukemia (AML M5a), originally presenting as granulocytic sarcoma of the testis, showing unusual cytogenetic abnormalities. tetrasomy 8 (primary) and t(15;17)(q22;q21) (secondary) were detected in bone marrow cells 6 months post-diagnosis, both by routine karyotype analysis and by fluorescence in situ hybridization (FISH) studies on metaphases and interphase nuclei. Retrospectively, the same abnormalities were identified in the primary testicular lesion using interphase FISH. However, reverse transcriptase polymerase chain reaction (RT-PCR) did not reveal the presence of a classic PML/RAR alpha fusion transcript. To the best of our knowledge, this is the first case to be reported in the literature of AML showing tetrasomy 8 in combination with secondary t(15;17).- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/130. Analysis of segregation and aneuploidy in two reciprocal translocation carriers, t(3;9)(q26.2;q32) and t(3;9)(p25;q32), by triple-color fluorescence in situ hybridization.Meiotic segregation patterns of chromosomes 3 and 9 were analyzed in sperm of two translocation carriers (t(3;9)(q26.2;q32) and t(3;9)(p25;q32)) by triple-color fluorescent in situ hybridization (FISH) with a telomeric dna probe in addition to two centromeric probes. The frequencies of each sperm product resulting from alternate or adjacent I, adjacent II and 3:1 segregation in a t(3;9)(q26.2;q32) translocation carrier were 88.35%, 5.44% and 5.94%, respectively. On the other hand, the frequencies of each sperm product in a t(3;9)(p25;q32) translocation carrier were 89.23%, 6.02% and 4.48%, respectively. Of all the sperm products, the frequency of normal or chromosomally balanced sperm in a t(3;9)(q26.2;q32) and a t(3;9)(p25;q32) were 52.49% and 47.25%, respectively. The frequencies of each sperm product resulting from various segregations were different between both carriers and significantly deviated from the expected frequencies. Additional dual-color and triple-color FISH were performed to analyze aneuploidy rates for chromosomes 12, 17, 18, X and Y in order to detect any interchromosomal effect; no evidence of an interchromosomal effect was found.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
8/130. Non-invasive exclusion of fetal aneuploidy in an at-risk couple with a balanced translocation.A pregnant woman who was a carrier for a balanced chromosome translocation [46,XX, t(1;6) (p31;q14)] and who had had six miscarriages, declined invasive testing but agreed to non-invasive prenatal diagnosis by analysis of fetal cells in maternal blood. Monoclonal antibody (Mab) against the zeta (z) and gamma (gamma) chains of embryonic and fetal haemoglobin were used to identify fetal nucleated erythrocytes (FNRBC). There were no FNRBC detected at 7 weeks, one anti-z-positive FNRBC was detected at 11 weeks, and 12 anti-gamma-positive FNRBC were detected at 20 weeks. Fluorescent in-situ hybridization was performed using probes for chromosomes X, Y, 1 and 6 to identify fetal gender and the presence of an unbalanced chromosomal translocation. A tentative prenatal diagnosis was made of a female fetus disomic for chromosomes 1 and 6. A female infant with a 46,XX karyotype was born at term. This is the first attempt of exclusion of a chromosome translocation using fetal cells isolated from maternal blood. There is an advantage of using fetal cells isolated from maternal blood for non-invasive prenatal diagnosis in couples who have a history of multiple miscarriages due to a parental translocation, and who decline invasive testing in a pregnancy that continues to the second trimester.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/130. Assessment of sex chromosome aneuploidy in sperm nuclei from 47,XXY and 46,XY/47,XXY males: comparison with fertile and infertile males with normal karyotype.Sex chromosome aneuploidy was assessed in spermatozoa from a 47,XXY male and a 46,XY/47,XXY male using three colour fluorescence in-situ hybridization (FISH) and compared with two control groups. The first group included subjects of proven fertility and the second infertile males with normal constitutional karyotype. The frequencies of XX and YY disomic, XY hyperhaploid and diploid spermatozoa were significantly increased in the 47,XXY male compared to subjects from the two control groups (P < 0.0001). For the 46,XY/47,XXY sample, the same results were observed, except that the incidence of YY disomic spermatozoa did not differ significantly from the rate obtained in infertile patients. The frequency of sex chromosome aneuploidy did not differ significantly between the 47,XXY and the 46,XY/47,XXY males, except for XX disomic sperm nuclei which was higher in the 47,XXY patient. The frequency of chromosome 12 disomy was also increased in the two XXY individuals (0.42 and 0.49% respectively; P < 0.0001). The meiotic abnormalities observed in the two XXY patients arose through segregation errors in XY germ cells. The increased number of meiotic non-disjunctions observed in the germ cells of infertile males may be a common feature of the deficient oligo- or azoospermic testis. patients with Klinefelter's syndrome with oligozoospermia have an increased risk of both sex chromosome and autosome aneuploidy in their progeny.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/130. Jumping translocations of 11q in acute myeloid leukemia and 1q in follicular lymphoma.Jumping translocation is a rare cytogenetic aberration in leukemia and lymphoma, and its etiologic mechanisms are not clearly known. We report two cases with jumping translocations. One had follicular lymphoma and jumping translocations of 1q onto the telomeric regions of 5p, 9p, and 15q in three cell lines, co-existing with the specific translocation t(14;18)(q32;q21). The second case had acute myeloid leukemia (AML) and jumping translocations of 11q as the sole aberration, onto multiple derivative chromosomes in each of the abnormal cells. A total of 17 telomeric regions were seen as the recipients of 11q in this case, and 9q was always involved as one of the recipients in all abnormal cells. fluorescence in situ hybridization (FISH) confirmed the identification of 11q material in the derivative chromosomes. While 1q has been the most common donor of acquired jumping translocations, this is the first report on jumping translocations of 11q. Different from all previously reported jumping translocations which involve only one recipient in each cell line and lead to a mosaic trisomy, multiple recipients in most of the abnormal cells in this case had led to a tetrasomy, or a pentasomy of 11q. The pattern of chromosome involvement as the recipients of 11q appears to show a continuing evolutionary process of jumping, stabilization, and spreading of the donor material into other chromosomes. Somatic recombinations between the interstitial telomeric or subtelomeric sequences of a derivative chromosome and the telomeric sequences of normal chromosomes are believed to be the underlying mechanism of jumping translocations and their clonal evolution.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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