Cases reported "monosomy"

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1/433. monosomy X as the sole cytogenetic abnormality in acute lymphoblastic leukemia: a report of two new patients.

    monosomy X as the sole acquired cytogenetic abnormality is usually found in myeloid hematological malignancies, especially those with myelodysplastic features. Only three cases of acute lymphoblastic leukemia (ALL) with this abnormality have been previously reported. We add two cases to this series and comment on the likelihood of a tumor suppressor gene being located on the x chromosome. ( info)

2/433. monosomy 18q syndrome and atypical rett syndrome in a girl with an interstitial deletion (18)(q21.1q22.3).

    We describe a 6 1/2-year-old girl with an interstitial deletion of chromosome arm 18q (18q21.1q22.3). Her clinical manifestations are a combination of those found in monosomy 18q syndrome and those of rett syndrome. cytogenetic analysis demonstrated a deletion of the long arm of chromosome 18, defined by molecular analysis with polymorphic markers as a de novo interstitial deletion, paternally derived. The findings typical of the 18q- syndrome included mental retardation, midface hypoplasia, and hypoplasia of labia majora, and those typical of rett syndrome were severe mental retardation, autistic behavior, inappropriate hand-washing movements, epilepsy, attacks of sighing and hyperventilation, and progressive scoliosis since the age of 5 years. She did not have microcephaly, and the mental delay was obvious from an early age without a period of normal development, which makes the diagnosis of rett syndrome atypical. Previously, a girl with mosaicism for a monosomy 18q associated with rett syndrome has been described. That girl had a terminal deletion of chromosome 18q, which seems to coincide in part with that in the present girl. It is possible that genes in the distal region of 18q are involved in the etiology of rett syndrome. ( info)

3/433. 'Identical' twins with discordant karyotypes.

    A chromosomal abnormality in one of the fetuses of a monozygotic twin pregnancy is a rare phenomenon. In the prenatal unit of our cytogenetics laboratory we have recently come across two such heterokaryotypic twin pregnancies. In both cases ultrasound abnormalities were detected in one fetus of each twin pair. Chromosomal analysis showed that one twin pregnancy was discordant for trisomy 21 and the other for 45,X. Ultrasonographic examination suggested a monochorionic twin pregnancy in each case and dna studies confirmed that both sets of twins were monozygotic. Both pregnancies were terminated. Biopsies taken from different sites of the placentas showed chromosomal mosaicism in both cases. There was no clear correlation between the karyotype found close to the site of the umbilical cord insertion in the placenta and the karyotype of the fetus. Sampling of amniotic fluid from both sacs is recommended in diamniotic twin pregnancies if one (or both) of the fetuses has ultrasound abnormalities, even if the twins are apparently monochorionic. ( info)

4/433. Detection of monosomy 7 in bone marrow by fluorescence in situ hybridization. A study of fanconi anemia patients and review of the literature.

    monosomy 7 is frequently found in the bone marrow of patients with fanconi anemia (FA), marrow myelodysplasia, or acute myelogenous leukemia and is associated with poor prognosis. In our laboratory, cytogenetic analysis of bone marrow from an FA patient found 2 of 30 cells with monosomy 7, but the results of fluorescence in situ hybridization (FISH) indicated that 83 of 207 cells (40%) had monosomy 7. FISH was then used to analyze two earlier samples from the index case, neither of which had monosomy 7 as determined by standard cytogenetics. The FISH analysis determined that the first sample, taken 19 months earlier, had 8 of 200 cells (4%) with monosomy 7 and the second sample. taken 7 months later, contained 43 of 200 cells (21.5%) with monosomy 7. These results indicate a slow evolution toward monosomy 7 in the patient's bone marrow. Standard metaphase chromosome analysis represents only spontaneously dividing cells, leading us to hypothesize that FISH was detecting monosomy 7 in nondividing cells and that it might be useful in the early detection of abnormal clones. To test this hypothesis, FISH was performed on 13 bone marrow samples from nine patients with FA who did not exhibit monosomy 7 by cytogenetic analysis. monosomy 7 was detected in 3.44% of nuclei in FA patients and in 3% of nuclei in normal controls. To date, none of these nine FA patients have developed monosomy 7 or leukemia. They are being monitored by standard cytogenetics and by FISH to determine whether monosomy 7 develops and whether it can be detected by FISH prior to its detection by standard cytogenetics. As standard practice, we have adopted FISH analysis for monosomy 7 in all patients with FA. ( info)

5/433. posterior leukoencephalopathy syndrome may not be reversible.

    The association of an acute reversible encephalopathy with transient occipital lobe abnormalities on imaging studies is well known. This condition has been called reversible posterior leukoencephalopathy syndrome. The clinical presentation usually includes seizures, headache, altered mental status, and blindness, often associated with hypertension and immunosuppressants. The authors discuss a two-year-old male with down syndrome who presented 2 months after allogeneic bone marrow transplantation with severe oculogyric crisis, without other complaints. The patient was being treated for hypertension and was receiving cyclosporine for prophylaxis of graft-vs-host disease. A computed tomography scan of the head revealed marked bilateral lucencies mainly involving the white matter of the occipital lobes, with a few foci of punctate hemorrhage. The condition improved when cyclosporine was discontinued, but an area of leukomalacia was identified on follow-up magnetic resonance imaging. To the authors' knowledge, oculogyric crisis as a presentation of reversible posterior leukoencephalopathy has not been previously described. Recognizing this association is important, because patients receiving cyclosporine are often receiving other medications that can potentially cause dystonic eye movements, possibly leading to a delay in diagnosis and treatment, which can result in an irreversible neurologic deficit. ( info)

6/433. Investigation of two cases of paternal disomy 13 suggests timing of isochromosome formation and mechanisms leading to uniparental disomy.

    uniparental disomy (UPD) is the abnormal inheritance of two copies of a chromosome from the same parent. Possible mechanisms for UPD include trisomy rescue, monosomy rescue, gametic complementation, and somatic recombination. Most of these mechanisms can involve rearranged chromosomes, particularly isochromosomes and Robertsonian translocations. Both maternal and paternal UPD have been reported for most of the acrocentric chromosomes. However, only UPD for chromosomes 14 and 15 show an apparent imprinting effect. Herein, we present two cases of paternal UPD 13 involving isochromosomes. Both cases were referred for UPD studies due to the formation of a de novo rea(13q13q). Case 2 was complicated by the segregation of a familial rob(13q14q) of maternal origin. Both propositi were phenotypically normal at the time of examination. Polymorphic marker analysis in Case 1 showed the distribution of alleles of markers along chromosome 13 to be complete isodisomy, consistent with an isochromosome. This rearrangement could have occurred either meiotically, without recombination, or mitotically. A likely mechanism for UPD in this case is monosomy rescue, through postzygotic formation of the isochromosome. In Case 2 the distribution of proximal alleles indicated an isochromosome, but recombination was evident. Thus, this isochromosome must have formed prior to or during meiosis I. A likely mechanism for UPD in this case is gametic complementation, since the mother carries a rob(13q14q) and is at risk of producing aneuploid gametes. However, trisomy rescue of a trisomy 13 conceptus cannot be completely excluded. Given that both cases were phenotypically normal, these data further support that paternal UPD 13 does not have an adverse phenotypic outcome and, thus, does not show an apparent imprinting effect. ( info)

7/433. Myelodysplastic syndrome with monosomy 7 after immunosuppressive therapy in Behcet's disease.

    Only few cases of Behcet's and hematological malignancies have been reported until now. We recently observed a 39-year-old female patient with Behcet's disease developing a myelodysplastic syndrome (MDS) FAB subtype refractory anemia with excess of blasts in transformation [RAEB-t] with a monosomy 7 after being treated with cyclosporin A and chlorambucil for several years. This case is reported and the occurrence of hematological malignancies and Behcet's disease is reviewed. ( info)

8/433. Myelodysplastic syndrome with monosomy 5 and/or 7 following therapy with 2-chloro-2'-deoxyadenosine.

    A few cases of secondary neoplasms occurring after treatment with 2-chloro-2'-deoxyadenosine (2CdA) have been reported, mostly in patients previously exposed to other anti-cancer drugs including alkylating agents (AA). Here we report on the occurrence of a myelodysplastic syndrome (MDS) with monosomy 5 and/or 7 in two patients after 2CdA treatment, without or prior to other toxic exposure. In light of a literature review and given the involvement of chromosomes frequently abnormal in secondary leukaemias, we suggest that 2CdA may induce therapy-related MDS (t-MDS). ( info)

9/433. Intracytoplasmic sperm injection pregnancy with trisomy 20p and monosomy 22q in a newborn resulting from a balanced paternal translocation.

    In infertile men who carry a balanced reciprocal translocation, intracytoplasmic sperm injection (ICSI) may induce a pregnancy with an abnormal karyotype. This report describes a previously unreported paternal reciprocal translocation leading to a chromosomally unbalanced ICSI pregnancy. The triplet pregnancy resulted in 1 normal girl, 1 physically normal boy with the same balanced paternal translocation, and a severely malformed boy with trisomy 20p and monosomy 22q who died in the neonatal period. ( info)

10/433. Lineage switch in childhood leukemia with monosomy 7 and reverse of lineage switch in severe combined immunodeficient mice.

    Morphophenotypic lineage switches occur in a small percentage of those with acute leukemia, and the underlying mechanisms are not clear. In this study, we attempted to induce a lineage switch in acute myelocytic leukemia (AML) with monosomy 7, whose lineage had switched from acute T-lymphocytic leukemia (T-ALL) during chemotherapy, in severe combined immunodeficient (SCID) mice. Although the transplanted myeloid cells were engrafted in SCID mice without cytokine administration, T-ALL developed in SCID mice treated with recombinant human granulocyte-macrophage colony-stimulating factor or recombinant human interleukin 3. Analysis of the nucleotide sequences of the rearranged T-cell receptor gamma-chain (TCR-gamma) gene revealed that this lineage switch resulted from the selection of the T-lineage subclone in SCID mice, which had expanded at onset. In addition, we found that the T-lineage and myeloid cells belonged to the distinct subclones, which were different in TCR-gamma gene rearrangements, but were derived from a common clone with an identical N-ras gene mutation for both subclones. In in vitro cultures, only the myeloid subclone grew; the T-lineage subclone failed to grow even in the presence of recombinant human granulocyte-macrophage colony-stimulating factor or recombinant human interleukin 3. These results suggested that the initial diagnostic T-lymphoid subclone, whose growth was dependent on these cytokines and the hematopoietic microenvironment, emerged from a bipotential T-lymphoid/myeloid leukemic stem cell, and further genetic event(s) induced the myeloid subclone, which grew independently of these cytokines and the microenvironment. ( info)
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