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The effect of ascertaining on estimates of the frequency of parental chromosome abnormalities in couples with a previous history of pregnancy wastage was investigated by comparing three samples which differ in the ascertainment modality but not in the cytogenetical approach. The incidence of chromosome abnormalities was higher in the sample of 441 couples selected essentially on clinical criteria (6%) than in the two samples (659 and 479 couples) selected retrospectively from the files of two cytogenetic laboratories (4.6 and 3.2%). The comparison of these results with similar data, based on large samples reported in the literature, indicated that sample size may be relevant in producing the wide ranges of variation of the frequency of chromosomal abnormalities. Using our data and those from three other samples of >300 couples a reasonable estimate of the overall incidence of chromosomal abnormalities in couples with a previous history of fetal wastage is ˜5%. [ABSTRACT FROM PUBLISHER]

Chromosome and enzyme determinations were performed in 250 pregnancies between the 7th and the 12th week of gestation. The majority of the tests were performed for risk of chromosomal abnormalities and 75% of the women were 35 years old or more. We describe a chorionic villi sampling (CVS) technique which proved to be highly efficient, with a diagnostic success rate of 97.7%. In the light of our experience we suggest that CVS is best performed between the 9th and 10th weeks of pregnancy. The average weight of the aspirated specimen was 20 mg with a lower limit of 5 mg which proved sufficient for diagnostic purposes. No major maternal complications were encountered and the slight bleeding observed in 14% of the cases during the days following the CVS should be considered a harmless effect of the aspiration technique. The proportion of fetal losses may lie between 4 and 7%. Paediatric monitoring of the 93 infants born so far and ultrasound examination of the pregnancies still in progress at the time of writing did not reveal any negative effect of CVS. Fetal-maternal transfusion and intrauterine infection are problems which need further basic investigations. [ABSTRACT FROM PUBLISHER]

Fetal chromosome analysis in a twin pregnancy during the first trimester is described. Problems of the reliability of tissue sampling are also discussed. The authors emphasise the advantage of direct cytogenetic analysis from the tissue specimens used for enzyme determination or DNA studies. [ABSTRACT FROM PUBLISHER]

The largest multi-gene family in metazoans is the family of olfactory receptor (OR) genes. Human ORs are organized in clusters over most chromosomes and seem to include >0.1% the human genome. Because 369 out of 856 OR genes are mapped on chromosome 11 (HSA11), we sought to determine whether they mediate structural rearrangements involving this chromosome. To this aim, we analyzed 220 specimens collected during diagnostic procedures involving structural rearrangements of chromosome 11. A total of 222 chromosomal abnormalities were included, consisting of inversions, deletions, translocations, duplications, and one insertion, detected by conventional chromosome analysis and/or fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (array-CGH). We verified by bioinformatics and statistical approaches the occurrence of breakpoints in cytobands with or without OR genes. We found that OR genes are not involved in chromosome 11 reciprocal translocations, suggesting that different DNA motifs and mechanisms based on homology or non-homology recombination can cause chromosome 11 structural alterations. We also considered the proximity between the chromosomal territories of chromosome 11 and its partner chromosomes involved in the translocations by using the deposited Hi-C data concerning the possible occurrence of chromosome interactions. Interestingly, most of the breakpoints are located in regions highly involved in chromosome interactions. Further studies should be carried out to confirm the potential role of chromosome territories' proximity in promoting genome structural variation, so fundamental in our understanding of the molecular basis of medical genetics and evolutionary genetics., Competing Interests: Declaration of interests At the time of data collection, F.R.G. was, together with F.M., V.Z., and E.R., a full-time employee of TOMA Advanced Biomedical Assays S.p.A. (Impact Lab) without ownership shares. F.R.G. is currently a full-time employee of Menarini Silicon Biosystems, Reproductive Precision Medicine Unit., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The presence of thousands of repetitive sequences makes the centromere a fragile region subject to breakage. In this study we collected 31 cases of rearrangements of chromosome 18, of which 16 involved an acrocentric chromosome, during genetic screening done in three centers. We noticed a significant enrichment of reciprocal translocations between the centromere of chromosome 18 and the centromeric or pericentromeric regions of the acrocentrics. We describe five cases with translocation between chromosome 18 and an acrocentric chromosome, and one case involving the common telomere regions of chromosomes 18p and 22p. In addition, we bring evidence to support the hypothesis that chromosome 18 preferentially recombines with acrocentrics: (i) the presence on 18p11.21 of segmental duplications highly homologous to acrocentrics, that can justify a NAHR mechanism; (ii) the observation by 2D-FISH of the behavior of the centromeric regions of 18 respect to the centromeric regions of acrocentrics in the nuclei of normal subjects; (iii) the contact analysis among these regions on published Hi-C data from the human lymphoblastoid cell line (GM12878).

The cytogenetic hallmark of Chronic Myeloid Leukemia (CML) is the presence of Philadelphia (Ph) chromosome, which results from a reciprocal translocation t(9;22)(q34;q11). In this report, we describe a CML patient with no evidence of Ph chromosome but trisomy of chromosome 8 as single cytogenetic abnormality and a typical e14a2 (b3a2) BCR-ABL1 fusion transcript. Fluorescence In Situ Hybridization (FISH) analysis revealed an uncommon signal pattern: the fusion signals were located on both copies of chromosome 22. During the course of the disease the appearance of the p.(Tyr315Ile) mutation was recorded. To the best of our knowledge this is the first Ph chromosome-negative CML case with e14a2 (b3a2) BCR-ABL1 transcript and p.(Tyr315Ile) mutation., Competing Interests: Conflict of interest: The authors declare no potential conflict of interest., (©Copyright: the Author(s).)

Satellited non-acrocentric autosomal chromosomes (ps-qs-chromosomes) are the result of an interchange between sub- or telomeric regions of autosomes and the p arm of acrocentrics. The sequence homology at the rearrangement breakpoints appears to be, among others, the most frequent mechanism generating these variant chromosomes. The unbalanced carriers of this type of translocation may or may not display phenotypic abnormalities. With the aim to understand the causative mechanism, we revised all the ps-qs-chromosomes identified in five medical genetics laboratories, which used the same procedures for karyotype analysis, reporting 24 unrelated cases involving eight chromosomes. In conclusion, we observed three different scenarios: true translocation, benign variant and complex rearrangement. The detection of translocation partners is essential to evaluate possible euchromatic unbalances and to infer their effect on phenotype. Moreover, we emphasize the importance to perform both, molecular and conventional cytogenetics methods, to better understand the behavior of our genome., Competing Interests: The authors declare no conflict of interest.

Chromosomal anomalies are well known to be an important cause of infertility, sterility and pregnancy loss. Balanced Reciprocal Translocation Mosaicism (BRTM) is an extremely rare phenomenon, mainly observed in subjects with a normal phenotype accompanied by reproductive failure. To date the mechanism of origin and the incidence of BRTM are poorly defined. Here we describe 10 new cases of BRTM. In 9 cases chromosome analysis revealed the presence of two different cell lines, one with a normal karyotype and the second with an apparently balanced reciprocal translocation. In the remaining case, both cell lines showed two different, but apparently balanced, reciprocal translocations. We document the clinical implications of BRTM, discuss its frequency in our referred population and suggest that carrier individuals might be more frequent than expected., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Purpose: To uncover underlying mutations in a cohort of Italian patients with aniridia, a rare congenital panocular condition with an incidence ranging from 1:64,000 to 1:100,000. The disease may be found isolated or in association with other syndromes characterized by partial or complete absence of the iris and iris hypoplasia., Methods: We analyzed the PAX6 gene in 11 patients with aniridia fulfilling the following inclusion criteria: partial or complete absence of the iris and age < 18 years at the time of diagnosis. DNA sequence analysis was integrated with Multiple Ligation Probe Assay (MLPA) analysis., Results: We identified seven PAX6 mutations, including four novel ones. The majority of mutations lie in the DNA-binding domain and all produce a truncated protein. All tested patients did not have WT1 gene deletions thus excluding the WAGR syndrome. We present the clinical findings in the four cases harboring novel mutations. We were unable to identify mutations in four cases with complete aniridia thus indicating that other gene/s could be involved in the disease., Conclusions: It is important to establish the molecular diagnosis early to avoid repeated and long-term screening for Wilms tumor. Our work further emphasizes that a wide range of ocular phenotypes are associated with loss of function PAX6 mutations. In addition to the possibility of stochastic variations, other genetic variations could play a role as modifier genes, thus giving rise to the observed different ocular phenotypes.

Background: Small supernumerary marker chromosomes (sSMCs) are additional, structurally abnormal chromosomes, generally smaller than chromosome 20 of the same metaphase spread. Due to their small size, they are difficult to characterize by conventional cytogenetics alone. In regard to their clinical effects, sSMCs are a heterogeneous group: in particular, sSMCs containing pericentromeric euchromatin are likely to be associated with abnormal outcomes, although exceptions have been reported. To improve characterization of the genetic content of sSMCs, several approaches might be applied based on different molecular and molecular-cytogenetic assays, e.g., fluorescent in situ hybridization (FISH), array-based comparative genomic hybridization (array CGH), and multiplex ligation-dependent probe amplification (MLPA).To provide a complementary tool for the characterization of sSMCs, we constructed and validated a new, FISH-based, pericentromeric Bacterial Artificial Chromosome (BAC) clone set that with a high resolution spans the most proximal euchromatic sequences of all human chromosome arms, excluding the acrocentric short arms., Results: By FISH analysis, we assayed 561 pericentromeric BAC probes and excluded 75 that showed a wrong chromosomal localization. The remaining 486 probes were used to establish 43 BAC-based pericentromeric panels. Each panel consists of a core, which with a high resolution covers the most proximal euchromatic ~0.7 Mb (on average) of each chromosome arm and generally bridges the heterochromatin/euchromatin junction, as well as clones located proximally and distally to the core. The pericentromeric clone set was subsequently validated by the characterization of 19 sSMCs. Using the core probes, we could rapidly distinguish between heterochromatic (1/19) and euchromatic (11/19) sSMCs, and estimate the euchromatic DNA content, which ranged from approximately 0.13 to more than 10 Mb. The characterization was not completed for seven sSMCs due to a lack of information about the covered region in the reference sequence (1/19) or sample insufficiency (6/19)., Conclusions: Our results demonstrate that this pericentromeric clone set is useful as an alternative tool for sSMC characterization, primarily in cases of very small SMCs that contain either heterochromatin exclusively or a tiny amount of euchromatic sequence, and also in cases of low-level or cryptic mosaicism. The resulting data will foster knowledge of human proximal euchromatic regions involved in chromosomal imbalances, thereby improving genotype-phenotype correlations.

There have been reports that a number of patients with a chromosome 18pter deletion have developed autoimmune disorders, including juvenile diabetes, rheumatoid arthritis, thyroiditis and Graves' disease, and/or show little or no reduction in serum IgA levels. We describe two female patients bearing complex rearrangements involving chromosome 18p. Array-CGH and BAC FISH molecular cytogenetic analyses enabled the precise identification of the affected 18p region. One patient has a 2 Mb terminal deletion associated with a 9.2 Mb inverted duplication of the adjacent region; the other has a more extended 10.1 Mb terminal deletion associated with a 4.1 Mb quadruplication of the adjacent region and a 2.6 Mb duplication of the pericentromeric region. Both patients have dysmorphic features typical of 18p deletion syndrome, such as growth retardation, epicanthal folds, a long philtrum and toe defects, and are also affected by immunological disorders. One has a form of immunological deficiency that takes the form of recurrent pulmonary infections and low IgA levels; the other has an autoimmune form of juvenile rheumatoid arthritis. Relating the refined molecular cytogenetic characterisation of these 18p chromosomal rearrangements to the patients' specific clinical characteristics can improve our understanding of the role of the 18p region in immune responses., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

Secondary myelodysplastic syndrome/acute myelogenous leukemia (MDS/AML) are today considered a primary complication of autologous hematopoietic stem cell transplantation. In our Center, 83 autografted patients underwent bone marrow (BM) biopsy and cytogenetic analysis at fixed intervals. Twelve patients developed non-clonal cytogenetic abnormalities and 10 patients clonal abnormalities, five of whom (three - 7, one - 5 and one t(9;11)) developed secondary MDS/AML. MDS was also diagnosed in two patients with a normal karyotype. In brief, seven patients (three males, four females; median age 36 years) developed MDS/AML 12-48 months (median 14) after autografting. The FAB diagnosis was AML-M2 in one, chronic myelomonocytic leukemia in two and refractory anemia with excess of blasts in transformation in four cases. Two patients presented a BM biopsy picture of MDS with fibrosis; none of them experienced leukemic transformation. Four MDS patients died, three of leukemic transformation and one of BM insufficiency; the two remaining patients are still living and untransformed. Our data underline the leukemogenic role of previous treatments, even if it is not possible to exclude that underlying disease and/or conditioning therapy may be involved.

Background and Objective: Myelodysplastic syndrome progenitor cells can be grown and expanded in long term bone marrow liquid cultures in the presence of multiple cytokines. In this study we investigated the pattern of differentiation and response to growth factors in six cases of myelodysplastic syndrome (MDS) with well-defined cytogenetic abnormalities by means of conventional cytogenetics and fluorescence in situ hybridization (FISH)., Methods: Bone marrow cells were grown in stroma-free liquid cultures in the presence of SCF, IL-3, IL-6 and GM-CSF., Results: IN three cases a CFU-GM expansion comparable to normal controls was observed, together with a decrease or increase of cells with abnormal karyotype. Two cases showed no response to growth factor stimulation, morphological signs of terminal myeloid differentiation and increase (one case) or decrease (one case) in the percentage of abnormal FISH signals along the cultures. In one additional case, while CFU-C expansion was present, clearcut leukemic transformation was observed in the culture, together with a sharp decrease in the percentage of abnormal FISH signals, indicating a leukemic transformation of MDS progenitor cells with a normal karyotype., Interpretation and Conclusions: Our data indicate that FISH analysis is generally a poor indicator of clonality in MDS; nevertheless, determining the kinetics of cytogenetically abnormal clones in liquid bone marrow cultures may provide insight as to the growth abnormalities of MDS progenitor cells and may be useful prior to in vivo growth factor administration.

Umbilical cord blood (CB) has been widely used for related and unrelated transplants in pediatric patients. We present the case of an adult with secondary AML who received an unrelated, one-antigen mismatched CB transplant due to the lack of a matched donor. The patient was a 26-year-old female (35 kg/bw) who had received an autologous bone marrow transplant for Hodgkin's disease in April 1994 and, 6 months later, developed secondary MDS (RAEB, 46, XX, -7, +mar), which slowly evolved into acute myelogenous leukemia. In May 1995, she was transplanted with a 165 ml CB unit containing a total of 1.6 x 10(9) nucleated cells, 11 x 10(6) CD34+ cells and 7.2 x 10(5) CFU-GM. GVHD prophylaxis consisted of standard CsA and methotrexate. Myeloid engraftment occurred on day +28 (PMN > 500) and full donor chimerism was confirmed twice (on days +33 and +56) by means of cytogenetics and DNA microsatellite analysis. Erythroid and megakaryocytic engraftment was documented by immunohistochemical analysis of a bone marrow biopsy on day +40, showing the presence of erythroblastic islands and isolated CD61+ immature cells. The patient did not develop GVHD but died on day +56 from idiopathic interstitial pneumonia and multiorgan failure. To our knowledge, this is one of the first case reports of unrelated mismatched CB transplantation in an adult.

Clonal chromosome and/or hematological abnormalities typically observed in myelodysplastic syndromes (MDS) have been described with increased frequency after autologous bone marrow transplantation (BMT) for lymphoma. We report the case of a woman with chronic myelogenous leukemia (CML) allografted with her HLA-identical sibling who, 5 years after the transplant and under immunosuppressive treatment for chronic graft host disease (GVHD), suffered a cytogenetic relapse associated with a 5q- deletion in the host metaphases. These findings suggest that myelodysplastic changes, possibly related to the chemo-radiotherapy conditioning regimen, may also present after allogeneic BMT.

Nine Italian and 12 German children fulfilled the criteria of myelodysplastic syndromes (MDS), according to the French-American-British (FAB) classification. All patients belonged to the more aggressive subtypes of myelodysplastic syndromes. Four presented with refractory anemia with excess of blasts (RAEB), 16 presented with refractory anemia with excess of blasts in transformation (RAEB-T), and 1 had chronic myelomonocytic leukemia (CMML). Dyserythropoiesis and dysgranulopoiesis were seen in all patients, and dysmegakaryopoiesis was seen in most patients. Cytogenetic studies in 13 of the 21 children showed karyotype abnormalities in 8; 5 had monosomy 7. Eleven patients were treated with intensive chemotherapy soon after diagnosis; 6 achieved complete remission (CR), and 2 of them are alive and still in complete remission after 48 and 69 months. Low-dose cytosine arabinoside (Ara-C) was given in six children without improvement. Bone marrow transplantation after progression of the disease has produced complete remission lasting 28 + months now in one of two patients. Four patients received only symptomatic treatment. The rate of 5-year survival for the total group was 20% (SD 9%). We conclude that children with MDS may benefit from more aggressive treatment, but that in general the survival rate is poor and similar to that observed in adults with the same subtypes of this disease.

Nine cases of acute leukemia presenting unusual phenotype were studied by light microscopy (LM) cytochemistry and transmission electron microscopy (TEM) immunocytochemistry with the immunogold staining (IGS) method; in addition, cytogenetic and molecular analyses were performed. The presence of myeloperoxidase (MPO) was studied at TEM in combination with immunophenotype to identify minor populations not characterizable at LM. Four of nine cases had no TEM/MPO reactivity, whereas the remaining five showed variable percentages of positive cells. Of the MPO negative cases, one was a megakaryoblastic leukemia with a positive platelet peroxidase (PPO) reaction, and three were lymphoid. Among the peroxidase positive cases, the percentage of MPO reactive cells was higher at TEM than at LM examination. In case 5 TEM analysis indicated that cells with some MPO reactivity at LM were non neoplastic myeloid cells. With this combined technique in cases 1 and 2 we excluded the presence of the MPO enzyme in CD15 positive lymphoid cells and, in another case, we documented the existence of CD19/MPO positive cells. The value of cytochemistry and immunology at the ultrastructural level for the characterization of blast cells and for the precise diagnosis of leukemia with "unusual" phenotype is illustrated.