Constitutional and acquired trisomy 8

t(9;22)(q34;q11.2) is a recurrent constitutional non-Robertsonian translocation and a rare cytogenetic mimic of chronic myeloid leukemia

The diagnosis of hematologic malignancy can be greatly aided by the detection of a cytogenetic abnormality. However, care must be taken to ensure that constitutional chromosomal abnormalities are not misattributed to a putative population of malignant cells. Here we present an unusual case in which a constitutional balanced t(9;22)(q34;q11.2) cytogenetically mimicked the acquired, t(9;22)(q34;q11.2), that is characteristic of chronic myeloid leukemia. Of special note, fluorescence in situ hybridization (FISH) analysis for this constitutional translocation (9;22)(q34;q11.2) using standard probes for BCR and ABL1 resulted in an abnormal pattern that was potentially misinterpretable as a BCR-ABL1 fusion. This is the first reported FISH analysis of a constitutional t(9;22)(q34;q11.2), and overall only the second report of such an abnormality. In light of the isolated prior report, our case also suggests that the constitutional t(9;22)(q34;q11.2) is one of the very few recurrent constitutional non-Robertsonian translocations described in humans. Our case underscores the necessity of complete clinical and laboratory correlation to avoid misdiagnosis of myeloid malignancy in the setting of rare constitutional cytogenetic abnormalities.

[Language development impairment and trisomy 8 mosaicism]

Constitutional trisomy 8 mosaicism (46,XX/47,XX,+8 or 46,XY/47,XY,+8) is characterized by trisomic distribution of chromosomes in some but not all cells of the body. The full condition presents with physical stigmata, skeletal abnormalities and a mild to moderate cognitive impairment.Here we present a boy aged 3 years 10 months with partial trisomy 8 who was referred because of a language impairment. Because of known anomalies (corpus callous agenesis, deformities of the spine) a chromosomal analysis was initiated.This case highlights the necessity for an interdisciplinary diagnostic approach in children with language impairment and other constitutional disorders.

Constitutional aneuploidy and cancer predisposition

Constitutional aneuploidies are rare syndromes associated with multiple developmental abnormalities and the alterations in the risk for specific cancers. Acquired somatic chromosomal aneuploidies are the most common genetic aberrations in sporadic cancers. Thus studies of these rare constitutional aneuploidy syndromes are important not only for patient counseling and clinical management, but also for deciphering the mechanisms by which chromosomal aneuploidy affect cancer initiation and progression. Here we review the major constitutional aneuploidy syndromes and suggest some general mechanisms for the associated cancer predisposition.

Trisomy 8 in an allogeneic stem cell transplant recipient representative of a donor-derived constitutional abnormality

Trisomy 8 is a common cytogenetic abnormality in myeloid malignancies. It can also be present constitutionally and is associated with a wide range of phenotypes. We report a case of a 20-year-old woman with acute myelogenous leukemia associated with the 11q23/MLL translocation who underwent allogeneic hematopoietic stem cell transplantation (HSCT) from a healthy, unrelated 26-year-old female. Cytogenetics on a bone marrow biopsy and aspirate performed 71 days after transplant to evaluate pancytopenia identified trisomy 8 in 6 of 7 cells examined. The bone marrow was hypocellular but normal by morphology and flow cytometry. Fluorescent in situ hybridization (FISH) for the original 11q23/MLL translocation was negative. Chimerism analysis using multiplex polymerase chain reaction to amplify an informative short tandem repeat demonstrated 97% donor cells. These findings were confirmed by repeat bone marrow biopsies at Day 110 after transplant and 1 year after transplant. With resolution of comorbid illness, the patient's peripheral blood counts recovered and remained normal at 1 year after HSCT. FISH analysis of a cryopreserved sample of the donor graft showed trisomy 8 in 120 of 200 cells examined. This represents the first reported case of a person with constitutional trisomy 8 mosaicism serving as a stem cell donor. The case illustrates the importance of identifying donor-derived constitutional abnormalities to avoid the assumption that these cytogenetic abnormalities after HSCT are representative of malignant disease.

A novel t(8;18)(q13;q21) in acute monocytic leukemia evolving from constitutional trisomy 8 mosaicism

Constitutional trisomy 8 mosaicism (CT8M) has been considered to be the first mutation in multistep carcinogenesis. We describe the case of a 38-year-old woman with a normal phenotype who developed to acute monocytic leukemia with a novel t(8;18)(q13;q21). Chromosome analysis and spectral karyotyping showed 47,XX,+8,t(8;18)(q13;q21)[20]. Fluorescence in situ hybridization (FISH) demonstrated that the breakpoint at 18q21 was centromeric to the MALT1 and BCL2 genes. FISH also revealed that trisomy 8 was detected in buccal mucosa cells, indicating that trisomy 8 was a constitutional abnormality. These results suggest that t(8;18)(q13;q21) had a crucial role in the development of leukemia as the second mutation following CT8M.

Cytogenetic and histological features of a human embryo with homogeneous chromosome 8 trisomy

BACKGROUND

Homogeneous and complete trisomy 8 is extremely rare. With one recent neonatal exception, all reported cases have been mosaic, due to mitotic non-disjunction during early zygotic development. We report a case of chromosome 8 trisomy in a human embryo examined at Carnegie stage 11 (25 days post-fertilization). It presented severe cardiovascular and central nervous system malformations.

METHODS

The unusual bifid heart in this embryo spurred a detailed histological examination, karyotyping of a chorionic villus sample and subsequent FISH on inter-phase nuclei of intra-embryonic sections.

RESULTS

Trophoblast cells had a karyotype of 47,XX, +8. Within the embryo proper, FISH demonstrated that the trisomy 8 was homogeneous in embryonic as well as extra-embryonic tissues. FQ-PCR supports a meiosis I origin of non-disjunction. In sections, the pharyngeal arches (including cardiac outflow tract), forebrain, mesonephros and liver were absent. Somites and yolk sac blood vessels were irregularly shaped.

CONCLUSION

We show that homogeneous, intra-embryonic trisomy 8 is compatible with implantation and early human development. Molecular pathways that may be compromised and their impact on organogenesis are discussed.

Trisomy 8 as the sole chromosomal aberration in acute myeloid leukemia and myelodysplastic syndromes

Trisomy 8 as the sole abnormality is the most common karyotypic finding in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), occurring in approximately 5% and 10% of the cytogenetically abnormal cases, respectively. However, despite the high frequency of +8, much remains to be elucidated as regards its epidemiology, etiology, clinical impact, association with other chromosomal abnormalities, cell of origin, and functional and pathogenetic consequences. Here, we summarize and review these various aspects of trisomy 8, focusing on AMLs and MDS harboring this abnormality as a single change.

[Aberrations of chromosome 8 in myelodysplastic syndromes: clinical and biological significance]

INTRODUCTION

Rearrangements of any single chromosome in human karyotype have been reported in patients with pMDS.

OBJECTIVE

To examine the role of aberrations of chromosome 8 in pathogenesis, clinical presentation and progression of myelodysplastic syndromes.

METHOD

Cytogenetic analysis of bone marrow cells was carried out by direct method and by means of 24- and/or 48-hour unstimulated cell culture. Chromosomes were obtained by modified method of HG-bands.

RESULTS

On presentation, 109 out of 271 successfully karyo-typed patients (40,2%) had abnormal karyotypes. Among them, 22 patients (10.9%) had aberrations of chromosome 8. Ten patients had trisomy 8 as "simple" aberration whilst additional three cases had trisomy 8 included in "complex" karyo-types (> or =3 chromosomes). Cases with constitutional trisomy 8 mosaicism (CT8M) were excluded using the chromosome analyses of PHA-stimulated blood cultures. On the contrary, monosomy (seven patients) or deletion of chromosome 8 (two patients) were exclusively found in "complex" karyo-types. During prolonged cytogenetic follow-up, trisomy 8 was not recorded in evolving karyotypes. In contrast, trisomy 8 disappeared in two cases during subsequent cytogenetic studies, i.e. 23 and 72 months from diagnosis, accompanied in one patient with complete hematological remission. No difference regarding age, sex, cytopenia, blood and marrow blast count or response to treatment was found between patients with trisomy 8 as the sole aberration compared to those with normal cytogenetics. Median survival of patients with trisomy 8 as the sole aberration was 27 months, as compared to 32 months in patients with normal cytogenetics (p = 0.468), whilst median survival of patients with aberrations of chromosome 8 included in "complex" karyotypes was only 4 months.

CONCLUSION

Aberrations of chromosome 8 are common in patients with pMDS. The presence of a clone with trisomy 8 is not always the sign of disease progression or poor prognosis in MDS patients, in contrast to clones with aberrations of chromosome 8 manifesting the loss of genetic material.

Prolonged pancytopenia in a gene therapy patient with ADA-deficient SCID and trisomy 8 mosaicism: a case report

A patient with adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID) was enrolled in a study of retroviral-mediated ADA gene transfer to bone marrow hematopoietic stem cells. After the discontinuation of ADA enzyme replacement, busulfan (75 mg/m2) was administered for bone marrow cytoreduction, followed by infusion of autologous, gene-modified CD34+ cells. The expected myelosuppression developed after busulfan but then persisted, necessitating the administration of untransduced autologous bone marrow back-up at day 40. Because of sustained pancytopenia and negligible gene marking, diagnostic bone marrow biopsy and aspirate were performed at day 88. Analyses revealed hypocellular marrow and, unexpectedly, evidence of trisomy 8 in 21.6% of cells. Trisomy 8 mosaicism (T8M) was subsequently diagnosed by retrospective analysis of a pretreatment marrow sample that might have caused the lack of hematopoietic reconstitution. The confounding effects of this preexisting marrow cytogenetic abnormality on the response to gene transfer highlights another challenge of gene therapy with the use of autologous hematopoietic stem cells.

Constitutional trisomy 8 mosaicism with myelodysplastic syndrome complicated by intestinal Behcet disease and antithrombin III deficiency

Trisomy 8 is the most common acquired chromosomal abnormality associated with myeloid malignancy. As a constitutional trisomy 8 mosaicism (T8M), it exhibits an extremely variable phenotype. In addition, Behcet disease (BD) has been reported as an unusual complication of myelodysplastic syndrome (MDS). To our knowledge, 12 case reports of various hematologic malignancies in patients with T8M and 18 case reports of MDS with acquired trisomy 8 complicated by BD have been published to date. We report a case of constitutional T8M with MDS complicated by intestinal BD and antithrombin III deficiency.

Acute lymphoblastic leukemia in a patient with Greig cephalopolysyndactyly and interstitial deletion of chromosome 7 del(7)(p11.2 p14) involving the GLI3 and ZNFN1A1 genes

Greig cephalopolysyndactyly (GCPS; OMIM 175700) is an autosomal dominant condition caused by mutations of the gene GLI3, located on 7p13. To date, several cases of deletions and/or translocations involving this locus have been reported in patients with GCPS. GLI3 is a transcription factor from the GLI-Kruppel gene family that has been implicated in three distinct entities: GCPS, Pallister-Hall syndrome, and postaxial polydactyly type A. The zinc finger protein, subfamily 1, member 1 gene (ZNFN1A1; OMIM 603023), on 7p12, codes for a lymphoid-restricted zinc finger transcription factor, ZNFN1A1, also called IKAROS, that regulates lymphocyte differentiation and has been associated with the development of childhood leukemia. We present the case of a 9-year-old Latin-American boy who was referred for stem cell transplantation because of recurrent acute lymphoblastic leukemia (ALL). On evaluation, he was found to have dysmorphic features consistent with GCPS, including a prominent forehead, down-slanting palpebral fissures, 1-2-3 toe syndactyly, broad thumbs and first toes, and mild developmental delay. He had developed ALL at 5 years of age. Chromosome analysis of bone marrow and fibroblastic cells showed an interstitial deletion of chromosome arm 7p, del(7)(p11.2p14), in 74% and 44% of the cells, respectively. We performed FISH analysis with a BAC clone containing the ZNFN1A1 gene and demonstrated that it is contained in the deleted segment. To our knowledge, this is the first report of a patient with GCPS and leukemia. We hypothesize that constitutional deletion of the ZNFN1A1 gene in this patient may have resulted in an increased risk of lymphoid malignancy.

Trisomy 14pter --> q21: a case with associated ovarian germ cell tumor and review of the literature

We report a patient with trisomy X and a supernumerary marker chromosome. The marker chromosome was characterized by comparative genomic hybridization and shown to be derived from chromosome 14, resulting in trisomy for 14pter --> q21. The karyotype was thus redefined as 48,XXX,+mar.rev ish enh(14pterq21). The patient presented with facial dysmorphism and a high-pitched cry, exhibited severe developmental delay, and developed an aggressive ovarian immature teratoma. In this paper, we also review reports of 11 other patients with constitutional trisomy of the same chromosomal region. Previous studies have identified somatic gains of chromosome 14 in ovarian germ cell tumors. We propose that the constitutional gain of chromosomal 14 material may have predisposed to the development of this tumor.

Constitutional chromosome aberrations as pathogenetic events in hematologic malignancies

A predisposition to tumor development is associated with some constitutional chromosomal abnormalities. Investigations of families with an apparent hereditary cancer and constitutional chromosome rearrangements have led to the molecular identification of tumor suppressor genes. Under the somatic mutation theory for the development of cancer, two mutational events are required. The first step may be a constitutional event and the second an acquired genetic mutation. Cytogenetic studies were performed on 5633 bone marrow specimens from patients with hematologic malignancies from a single institution. Fifty cases of constitutional chromosome aberrations were detected. Data collected from the literature and from our series are reviewed and compared with the incidence of specific constitutional chromosome aberrations in the newborn population. Possible mechanisms that may predispose individuals with constitutional chromosome aberrations to the development of a hematologic malignancy are reviewed.

Two primary osteosarcomas in a patient with Rothmund-Thomson syndrome

Rothmund-Thomson syndrome is an autosomal recessive disorder characterized by poikilodermatous skin changes that develop in infancy. Associated manifestations include juvenile cataracts, sparse hair, short stature, skeletal defects, dystrophic nails and teeth, and hypogonadism. An increased incidence of malignancy, including osteosarcoma, has been reported in patients with Rothmund-Thomson syndrome. The molecular basis of the disorder is not known. This report describes a patient with Rothmund-Thomson syndrome in whom two primary osteosarcomas developed 12 years apart. The presentation, diagnosis, and treatment of osteosarcoma in this patient with Rothmund-Thomson syndrome are described. Cytogenetic and molecular analysis of peripheral blood and skin fibroblasts had low level mosaicism for trisomy of chromosomes 2 and 8. Although several patients have been described with mosaic trisomy 8 and i(2q) (mosaic isochromosome for the long arm of chromosome 2), the patient described here is the first to have mosaic trisomy for the entire chromosomes 2 and 8. The cytogenetic findings in this patient are consistent with an underlying defect in chromosomal stability.

Chronic myelomonocytic leukaemia in a child with constitutional partial trisomy 8 mosaicism

We present a 3-year-old boy with constitutional partial trisomy 8 mosaicism (karyotype 47,XY, + del(8)(p12)/46,XY) who developed chronic myelomonocytic leukaemia and we review the few reported cases of constitutional trisomy 8 mosaicism (CT8M) associated with malignancy. This case highlights the association between CT8M and the development of malignancies, haematological malignancies in particular.