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Simple Summary The world population is genetically and environmentally diverse. In particular, genetic differences related to an ethnic factor may underlie differences in cancer phenotypic expression. Therefore, we compared the epidemiology, and the clinical, biological and genetic characteristics of myelodysplastic syndrome (MDS) between Asian and Western countries. Our results show substantial differences in the incidence and age of onset between Asian and Western MDS patients. A higher proportion of Asian MDS patients fall into the high- and very-high risk prognostic MDS groups. This finding is supported by the identification of a higher proportion of high-risk cytogenetic aberrations in Asian MDS patients. However, the survival rate is similar for Western and Asian MDS patients. Our findings may impact the clinical management as well as the strategy of clinical trials targeting those genetic aberrations and mutations depending on the world area where they are run. Abstract This study explores the hypothesis that genetic differences related to an ethnic factor may underlie differences in phenotypic expression of myelodysplastic syndrome (MDS). First, to identify clear ethnic differences, we systematically compared the epidemiology, and the clinical, biological and genetic characteristics of MDS between Asian and Western countries over the last 20 years. Asian MDS cases show a 2- to 4-fold lower incidence and a 10-year younger age of onset compared to the Western cases. A higher proportion of Western MDS patients fall into the very low- and low-risk categories while the intermediate, high and very high-risk groups are more represented in Asian MDS patients according to the Revised International Prognostic Scoring System. Next, we investigated whether differences in prognostic risk scores could find their origin in differential cytogenetic profiles. We found that 5q deletion (del(5q)) aberrations and mutations in TET2, SF3B1, SRSF2 and IDH1/2 are more frequently reported in Western MDS patients while trisomy 8, del(20q), U2AF1 and ETV6 mutations are more frequent in Asian MDS patients. Treatment approaches differ between Western and Asian countries owing to the above discrepancies, but the overall survival rate within each prognostic group is similar for Western and Asian MDS patients. Altogether, our study highlights greater risk MDS in Asians supported by their cytogenetic profile.

Chronic lymphocytic leukemia (CLL) represents the most common hematological malignancy in Western countries, with a highly heterogeneous clinical course and prognosis. Translocations involving the immunoglobulin (IG) genes are regularly identified. From 2000 to 2014, we identified an IG gene translocation in 18 of the 396 patients investigated at diagnosis (4.6%) and in 17 of the 275 analyzed during follow-up (6.2%). A total of 4 patients in whom the IG translocation was identified at follow-up did not carry the translocation at diagnosis. The IG heavy locus (IGH) was involved in 27 translocations (77.1%), the IG κ locus (IGK) in 1 (2.9%) and the IG λ locus (IGL) in 7 (20.0%). The chromosome band partners of the IG translocations were 18q21 in 16 cases (45.7%), 11q13 and 19q13 in 4 cases each (11.4% each), 8q24 in 3 cases (8.6%), 7q21 in 2 cases (5.7%), whereas 6 other bands were involved once (2.9% each). At present, 35 partner chromosomal bands have been described, but the partner gene has solely been identified in 10 translocations. CLL associated with IG gene translocations is characterized by atypical cell morphology, including plasmacytoid characteristics, and the propensity of being enriched in prolymphocytes. The IG heavy chain variable region (IGHV) mutational status varies between translocations, those with unmutated IGHV presumably involving cells at an earlier stage of B-cell lineage. All the partner genes thus far identified are involved in the control of cell proliferation and/or apoptosis. The translocated partner gene becomes transcriptionally deregulated as a consequence of its transposition into the IG locus. With the exception of t(14;18)(q32;q21) and its variants, prognosis appears to be poor for the other translocations. Therefore, searching for translocations involving not only IGH, but also IGL and IGK, by banding and molecular cytogenetics is required. Furthermore, it is important to identify the partner gene to ensure the patients receive the optimal treatment.

Inv(16)(p13q22) and t(16;16)(p13;q22) are cytogenetic hallmarks of acute myelomonoblastic leukaemia, most of them associated with abnormal bone marrow eosinophils [acute myeloid leukaemia French-American-British classification M4 with eosinophilia (FAB AML-M4Eo)] and a relatively favourable clinical course. They generate a 5'CBFB-3'MYH11 fusion gene. However, in a few cases, although RT-PCR identified a CBFB-MYH11 transcript, normal karyotype and/or fluorescent in situ hybridization (FISH) analyses using commercially available probes are found. We identified a 32-year-old woman with AML-M4Eo and normal karyotype and FISH results. Using two libraries of Bacterial Artificial Chromosome clones on 16p13 and 16q22, FISH analyses identified an insertion of 16q22 material in band 16p13, generating a CBFB-MYH11 type A transcript. Although very rare, insertions should be searched for in patients with discordant cytological and cytogenetic features because of the therapeutic consequences. Copyright © 2015 John Wiley & Sons, Ltd.

Although 22q11.2 deletion syndrome (22q11.2DS) is the most recurrent human microdeletion syndrome associated with a highly variable phenotype, little is known about the condition's true incidence and the phenotype at diagnosis. We performed a multicenter, retrospective analysis of postnatally diagnosed patients recruited by members of the Association des Cytogénéticiens de Langue Française (the French-Speaking Cytogeneticists Association). Clinical and cytogenetic data on 749 cases diagnosed between 1995 and 2013 were collected by 31 French cytogenetics laboratories. The most frequent reasons for referral of postnatally diagnosed cases were a congenital heart defect (CHD, 48.6%), facial dysmorphism (49.7%) and developmental delay (40.7%). Since 2007 (the year in which array comparative genomic hybridization (aCGH) was introduced for the routine screening of patients with intellectual disability), almost all cases have been diagnosed using FISH (96.1%). Only 15 cases (all with an atypical phenotype) were diagnosed with aCGH; the deletion size ranged from 745 to 2904 kb. The deletion was inherited in 15.0% of cases and was of maternal origin in 85.5% of the latter. This is the largest yet documented cohort of patients with 22q11.2DS (the most commonly diagnosed microdeletion) from the same population. French cytogenetics laboratories diagnosed at least 108 affected patients (including fetuses) per year from among a national population of ∼66 million. As observed for prenatal diagnoses, CHDs were the most frequently detected malformation in postnatal diagnoses. The most common CHD in postnatal diagnoses was an isolated septal defect.

Aims & methods: We used interphase FISH to determine the incidence of chromosomal changes in 638 B-cell chronic lymphocytic leukemia patients. Results: Chromosomal abnormalities were found in some 75% of the patients. Del(13)(q14) was present in 57.3 and 57% of patients at diagnosis and during follow-up, respectively. It was followed by trisomy 12 (19 and 19.8% at diagnosis and during follow-up, respectively), del(11)(q22) (9.1 and 14.3% at diagnosis and during follow-up, respectively) and del(17)(p13) (2.8 and 12.4% at diagnosis and during follow-up, respectively). Discussion & conclusion: Our results correlate with those obtained in 55 studies reported in the literature. Trisomy 12 and del(13)(q14) are present in high proportions at diagnosis and are not enriched during progression, to the contrary of del(11)(q22) and del(17)(p13) that are markers of evolution.

Secondary acute lymphoblastic leukemia (sALL) following chemotherapy and/or radiotherapy of previous malignancies represents 2-10% of all cases of ALL. A 72-year-old female patient was diagnosed with acute lymphoblastic leukemia following chemotherapy for a diffuse large B cell lymphoma. Banding cytogenetics showed a t(t(5;11)(q23-31;q23) in 20 of the 21 metaphases examined and fluorescent in situ hybridization confirmed rearrangement of MLL. Long distance inverse-polymerase chain reaction revealed an in-frame fusion between 5'MLL and 3'PRRC1. Sixty-five cases of sALL associated with 11q23/MLL rearrangement, including 47 with a t(4;11)(q21;q23), were retrieved from the literature. Drug regimen used to treat the primary neoplasm was available for 54 patients; 52 had received a topoisomerase II inhibitor, known to induce MLL rearrangement.

Structural abnormalities of chromosome 7q have been regularly reported in chronic B-cell lymphoproliferative disorders. They include chromosomal translocations involving 7q21, leading to overexpression of the CDK6 gene. Three different translocations, t(7;14)(q21;q32), t(7;22)(q21;q11), and t(2;7)(p11;q21), leading to the juxtaposition of the CDK6 gene with a immunoglobulin gene enhancer during B-cell differentiation, have been described. In the past 2 years, we identified three patients with lymphoproliferative malignancy associated with a t(2;7)(p11;q21). Fluorescent in situ hybridization using an IGK probe and a library of bacterial artificial chromosome (BAC) clones located in bands 7q21.2 and 7q21.3, containing CDK6, revealed that the telomeric part of the IGK probe was translocated on the der(7) within a 51-kb region upstream of the transcriptional start site of CDK6. A total of 23 patients with indolent B-cell lymphoproliferative disorders and juxtaposition of the IG and CDK6 genes, including 20 with IGK and CDK6 juxtaposition, have been reported thus far. This rearrangement leads to the overexpression of CDK6, which encodes a cyclin-dependent protein kinase involved in cell cycle G1 phase progression and G1/S transition.

ABSTRACT: In humans, class I homeobox genes (HOX genes) are distributed in four clusters. Upstream regulators include transcriptional activators and members of the CDX family of transcription factors. HOX genes encode proteins and need cofactor interactions, to increase their specificity and selectivity. HOX genes contribute to the organization and regulation of hematopoiesis by controlling the balance between proliferation and differentiation. Changes in HOX gene expression can be associated with chromosomal rearrangements generating fusion genes, such as those involving MLL and NUP98, or molecular defects, such as mutations in NPM1 and CEBPA for example. Several miRNAs are involved in the control of HOX gene expression and their expression correlates with HOX gene dysregulation. HOX genes dysregulation is a dominant mechanism of leukemic transformation. A better knowledge of their target genes and the mechanisms by which their dysregulated expression contributes to leukemogenesis could lead to the development of new drugs.

Keywords: chronic lymphocytic leukaemia; chromosomal translocation; chromosome 13; DLEU2 ; micro-RNA

Translocations involving band 12p13 are one of the most commonly observed chromosomal abnormalities in human leukemia and myelodysplastic syndrome. Their frequently result in rearrangements of the ETV6 gene. At present, 48 chromosomal bands have been identified to be involved in ETV6 translocations, insertions or inversions and 30 ETV6 partner genes have been molecularly characterized. The ETV6 protein contains two major domains, the HLH (helix-loop-helix) domain, encoded by exons 3 and 4, and the ETS domain, encoded by exons 6 through 8, with in between the internal domain encoded by exon 5. ETV6 is a strong transcriptional repressor, acting through its HLH and internal domains. Five potential mechanisms of ETV6-mediated leukemogenesis have been identified: constitutive activation of the kinase activity of the partner protein, modification of the original functions of a transcription factor, loss of function of the fusion gene, affecting ETV6 and the partner gene, activation of a proto-oncogene in the vicinity of a chromosomal translocation and dominant negative effect of the fusion protein over transcriptional repression mediated by wild-type ETV6. It is likely that ETV6 is frequently involved in leukemogenesis because of the large number of partners with which it can rearrange and the several pathogenic mechanisms by which it can lead to cell transformation.

We report here a child with a ring chromosome 5 (r(5)) associated with facial dysmorphology and multiple congenital abnormalities. Fluorescent in situ hybridization (FISH) using bacterial artificial chromosome (BAC) clones was performed to determine the breakpoints involved in the r(5). The 5p deletion extended from 5p13.2-3 to 5pter and measured 34.61 Mb (range: 33.7–35.52 Mb) while the 5q deletion extended from 5q35.3 to 5qter and measured 2.44 Mb (range: 2.31–2.57 Mb). The patient presented signs such as microcephaly, hypertelorism, micrognathia and epicanthal folds, partially recalling those of a deletion of the short arm of chromosome 5 and the “cri-du-chat” syndrome. The most striking phenotypic features were the congenital heart abnormalities which have been frequently reported in deletions of the distal part of the long arm of chromosome 5 and in rings leading to a 5q35-5qter deletion. However, the NKX2-5 gene, which has been related to congenital heart defects, was not deleted in our patient, nor presumably to some other patients with 5q35.3-5qter deletion. We propose that VEGFR 3, deleted in our patient, could be a candidate gene for the congenital heart abnormalities observed.

Among various causes responsible for infertility, it has been admitted for a long time that male infertility can be due to impaired spermatogenesis and/or balanced structural chromosomal abnormalities. Sperm DNA fragmentation is also considered as another cause of infertility. Most of the studies on male infertility have concerned either aneuploidy in the sperm of carriers of constitutional chromosomal abnormalities or sperm DNA fragmentation. This review is aimed at analyzing these 2 parameters in the same patients. Furthermore, we present work on the study of these 2 parameters in the same gametes of 4 carriers of a balanced chromosomal abnormality. Meiotic segregation was analyzed by fluorescent in situ hybridization and DNA fragmentation was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. It was shown that aneuploidy and DNA fragmentation were increased in the sperm of carriers of a balanced chromosomal abnormality. For all 4 carriers of a balanced structural abnormality, there was a 2–5 times higher proportion of spermatozoa with unbalanced chromosomal content and fragmented DNA than among those with normal/balanced content. Moreover, we found a non-random distribution with more gametes with DNA fragmentation when these arose from a particular segregation mode. The mechanism which would tend to explain our results is abortive apoptosis. In conclusion, both meiotic segregation and DNA fragmentation studies should be integrated in the genetic exploration of male carriers of a chromosomal structural abnormality.

Resume Les tumeurs placentaires non trophoblastiques sont des lesions rares, tant primitives que secondaires, d’origine fœtale ou maternelle. Nous rapportons ici le cas d’un leiomyome intraplacentaire rencontre en contexte de mort fœtale in utero inexpliquee a terme. Ce cas pose le double probleme, d’une part, de l’origine de la tumeur, exploree en cytogenetique moleculaire et, d’autre part, des complications obstetricales imputables aux leiomyomes uterins.

The detection of chromosome abnormalities by conventional cytogenetics, now combined with analyses using fluorescence in situ hybridization (FISH), is an important component in assessing the risk stratification of acute lymphoblastic leukemia (ALL). Identification of specific chromosome abnormalities led to the recognition of genetic subgroups based on modal chromosomal number, reciprocal translocations in B-cell ALL, or both. We report here the cytogenetic analysis of 208 patients with pre-B and B-cell ALL referred to a single laboratory between 1981 and 2008. Chromosome abnormalities were observed in 82.9% of L1/L2 ALL patients and in 83.3% of L3 patients with successful analysis at diagnosis. The proportion of diploid karyotypes tended to decrease during the period of study, from 26% to 13%, in association with technical progress and the introduction of FISH techniques. As previously reported, the incidence of high hyperdiploidy (51-67 chromosomes) was higher among children, whereas pseudodiploidy and hypodiploidy were higher among those >15 years of age. Structural chromosome abnormalities were more frequently observed among patients older than 15 years than in children (75.9% vs. 68.5%, respectively). As previously reported, t(9;22)(q34;q11) and t(12;21)(p13;q21) were the most frequent structural rearrangements among adults (26.9%) and children (19.7%), respectively. Almost 17% of the patients studied at diagnosis had further cytogenetic analyses at relapse, the majority showing clonal evolution toward a more complex karyotype. Although the detection of chromosome abnormalities by conventional cytogenetics and FISH techniques is an important tool in assessing risk stratification of ALL, some patients lack abnormalities with clinical relevance. The use of array comparative genomic hybridization (aCGH) offers an alternative for identifying copy number alterations, but cannot detect balanced chromosomal rearrangements.

Chromosomal rearrangements involving the MLL gene, at chromosome band 11q23, are recurrently associated with the disease phenotype of acute leukemia. They have been associated with B-cell acute lym...

Dear Editor,The RUNX gene family includes three evolutionarilyconserved genes (RUNX1, RUNX2, and RUNX3) encodingtranscription factors involved in cell lineage differentiationduring development and various forms of cancer [1].RUNX1 gene (also known as AML1 PEBP2αB or CBFA2),located in chromosome 21q22.3, is crucial for the estab-lishment of definite hematopoiesis and the generation ofhematopoietic stem cells in the embryo. RUNX1 acts as akey regulator of hematopoiesis through the regulation ofvarious hematopoietic genes [1–3].RUNX1 impairment resulting from mutation, deletion,translocation, or amplification is reported to contribute tothe pathogenesis of acute leukemias [4]. We report heredistinct clonal anomalies involving the RUNX1 geneoccurring in the course of the disease in a patient withacute myeloblastic leukemia (AML).This 51-year-old man was first seen in February 2006because of persistent rhinitis and recurrent epistaxis.Physical examination showed no adenopathy or hepatos-plenomegaly. The peripheral blood count revealed aleukocytosis of 8.6×10

Resume Les marqueurs chromosomiques surnumeraires (MCS) sont des chromosomes additionnels dont la structure est indeterminee par les techniques de cytogenetique conventionnelle. Les MCS constituent un groupe heterogene d’anomalies chromosomiques de structure variable, pouvant etre associes ou non a des anomalies du phenotype. L’identification d’un MCS permet d’etablir une correlation phenotype–genotype, necessaire pour le conseil genetique. Afin de determiner l’origine et la composition d’un MCS, il existe differents outils moleculaires, tels que la FISH 24-couleurs (MFISH, SKY), la FISH multicouleurs specifique des centromeres (cenMFISH) et ses derives (subcenMFISH, AcroMFISH), la CGH, la CGH-array et les techniques ciblees telles que les peintures chromosomiques, les techniques de banding, les sondes centromeriques et les sondes locus specifiques. A partir de ces nombreuses techniques, en fonction de la taille, de l’aspect du MCS depiste par les techniques de cytogenetique conventionnelle, des donnees cliniques, il est possible de proposer differentes strategies moleculaires.

ABSTRACT The EVI1 gene, located in chromosomal band 3q26, is a transcription factor that has stem cell-specific expression pattern and is essential for the regulation of self-renewal of hematopoietic stem cells. It is now recognized as one of the dominant oncogenes associated with myeloid leukemia. EVI1 overexpression is associated with minimal to no response to chemotherapy and poor clinical outcome. Several chromosomal rearrangements involving band 3q26 are known to induce EVI1 overexpression. They are mainly found in acute myeloid leukemia and blastic phase of Philadelphia chromosome-positive chronic myeloid leukemia, more rarely in myelodysplastic syndromes. They include inv(3)(q21q26), t(3;3)(q21;q26), t(3;21)(q26;q22), t(3;12)(q26;p13) and t(2;3)(p15–23;q26). However, many other chromosomal rearrangements involving 3q26/EVI1 have been identified. The precise molecular event has not been elucidated in the majority of these chromosomal abnormalities and most gene partners remain unknown.

Inv(16)(p13q22) and t(16;16)(p13;q22) are cytogenetic hallmarks of acute myelomonoblastic leukaemia, most of them associated with abnormal bone marrow eosinophils [acute myeloid leukaemia French-American-British classification M4 with eosinophilia (FAB AML-M4Eo)] and a relatively favourable clinical course. They generate a 5'CBFB-3'MYH11 fusion gene. However, in a few cases, although RT-PCR identified a CBFB-MYH11 transcript, normal karyotype and/or fluorescent in situ hybridization (FISH) analyses using commercially available probes are found. We identified a 32-year-old woman with AML-M4Eo and normal karyotype and FISH results. Using two libraries of Bacterial Artificial Chromosome clones on 16p13 and 16q22, FISH analyses identified an insertion of 16q22 material in band 16p13, generating a CBFB-MYH11 type A transcript. Although very rare, insertions should be searched for in patients with discordant cytological and cytogenetic features because of the therapeutic consequences. Copyright © 2015 John WileySons, Ltd.

Several chromosomal rearrangements involving band 3q26 are known to induce EVI1 overexpression. They include inv(3)(q21q26), t(3;3)(q21;q26), t(3;21)(q26;q22) and t(3;12)(q26;p13). Translocations involving the short arm of chromosome 2 and 3q26 have been reported in more than 50 patients with myeloid disorders. However, although the breakpoints on 2p are scattered over a long segment, their distribution had only been analyzed in 9 patients. We performed fluorescent in situ hybridization with a library of BAC (Bacterial Artificial Chromosome) clones in 4 patients with t(2;3)(p15-23;q26). Our results combined with those of the 9 previously reported patients showed scattering of the breakpoints in 2 regions. A 1.08Mb region in band 2p21 encompassing the MTA3, ZFP36L2 and THADA genes was documented in 5 patients. A second region of 1.83Mb in band 2p16.1 was identified in 8 patients. Four patients showed clustering around the BCL11A gene and the remaining 4 around a long intergenic non-coding RNA, FLJ30838. These regions are characterized by the presence of regulatory sequences (CpG islands and promoters) that could be instrumental in EVI1 overexpression.

Short communication on on t(10;17)(p15;q21) ZMYND11/MBTD1, with data on clinics, and the genes implicated.

Complex chromosome rearrangements (CCRs) are structural rearrangements involving at least three chromosomes and three or more chromosome breakpoints. Generally, balanced CCR carriers have a normal phenotype but they are at a higher reproductive risk. Azoospermia was discovered in the male partner of a couple with primary infertility. Conventional cytogenetics identified a CCR refined by fluorescent in situ hybridisation. The CCR involved three chromosomes, four breakpoints and an insertion. A literature search identified 43 phenotypically normal males referred for reproductive problems presenting a CCR. More males were ascertained because of spermatogenesis failure or disturbances than because of repeated abortions and/or birth of a malformed child. Male carriers of CCR produce a high frequency of chromosomally abnormal spermatozoa due to the aberrant segregation of the rearranged chromosomes. The number of chromosomes and breakpoints involved in the rearrangement, the position of breakpoints, the relative size of the resultant chromosomes and the presence or absence of recombination inside the paired-rearranged segments are presumed to affect the fertility of the carrier. Testicular biopsy should not be performed in males with azoospermia. Intracytoplasmic sperm injection should not be proposed as a procedure for treating the infertility of CCR male carriers as a successful result is unlikely.

Review on t(20;21)(q13.2;q22.12) ZFP64/RUNX1, with data on clinics, and the genes involved.

Inv(3)(q21q26)/t(3;3)(q21;q26) is a feature of a distinctive entity of acute myeloid leukemia (AML) associated with normal or elevated platelet count, atypical megakaryocytes and multilineage dysplasia in the bone marrow, as well as minimal to no response to chemotherapy and poor clinical outcome. The presence of an inversion on both chromosome 3s is a rare event, as only eight cases have been reported in the literature. Recently, we identified two patients with AML carrying a double inv(3)(q21q26). Using librairies of bacterial artificial chromosome clones mapping to bands 3q21 and 3q26, we found that the regions in which the breakpoints occurred were different in both patients, but located in the same restricted areas in each patient. Although it cannot be excluded that inversion occurred independently on both chromosome 3s, it is more likely that the presence of a double inv(3) is the result of loss of the normal chromosome 3 followed by a duplication of the inverted chromosome, or segmental loss of heterozygosity followed by a somatic repair mechanism.

Chromosomal rearrangements involving the mixed-lineage leukemia (MLL) gene, located at chromosomal band 11q23, result in the generation of in-frame fusion transcripts with various partner genes from more than 60 distinct gene loci. Among them, the MLL/AFF1 (AF4/FMR2 family, member 1) fusion, associated with rearrangements between bands 4q21 and 11q23 is a recurrent event in pre-B acute lymphoblastic leukemia (ALL). Gene expression profiling (GEP) was performed for four adult patients with ALL. Their signatures were compared to those of ALL patients with a fusion gene involving c-abl oncogene 1, non-receptor tyrosine kinase (ABL1). The comparison of MLL-AFF1 cases with the ABL1 group identified 477 genes being differentially expressed at the statistically significant level of p0.05, with 296 and 181 genes up- and down-regulated, respectively, in the MLL-AFF1 cases. Three GEP studies on t(4;11)(q21;q23) focusing on the age group of the patients have been reported in the literature. Different expression profiles based on the levels of the homeobox A (HOXA) signature were identified. Although comparison between studies is difficult because of differences in the microarrays and the control samples used, our results and those from the literature suggest that cells carrying t(4;11)(q21;q23) use different pathways to lead to leukemogenesis. Therefore, t(4;11)-associated ALL could represent different biological entities.

This couple presented with a 4-year history of primary infertility. The male partner was found to have oligoasthenozoospermia. A supernumerary marker chromosome (SMC) was found. Fluorescent in situ hybridization (FISH) analyses showed that the SMC was a heterochromatic dicentric marker derived from chromosome 22. Further FISH procedures showed the rate of unbalanced spermatozoa containing one chromosome 22 and the SMC to be 15.6%. Due to the low risk of fetal chromosomal imbalance linked to the paternal SMC and the risk of miscarriage linked to the amniocentesis, the couple declined prenatal diagnosis. A healthy newborn baby was obtained after ICSI.

Review on i(5)(p10) in acute myeloid leukemia, with data on clinics, and the genes involved.

Molecular characterization of deletions of the long arm of chromosome 5 (del(5q)) in 94 MDS/AML patients

Williams-Beuren syndrome (WBS, MIM No. 194050) is a contiguous gene deletion syndrome that was described independently by Williams et al. (1961) in patients with supravalvular aortic stenosis, growth retardation and an unusual facial appearance (Williams et al., 1961) and by Beuren et al. (1962) in patients having the same features as well as dental anomalies and friendly personality (Beuren et al., 1962).

Disease Myelodysplastic syndrome (21 cases), Acute Myeloid Leukemia (5 cases), Chronic Myelomonocytic Leukemia (1 case). Phenotype/cell stem origin Thrombopenia (90%) with anemia (60%). Dysplastic changes in bone marrow: dyserythropoeisis associated with dysgranulopoieisis and/or dysmegakaryocytopoeisis. Epidemiology The frequency of ider(20q) is estimated at 0.49% in myelodysplastic syndrome and 0.26% in acute myeloid leukemia according to one study. They are found in older patients (average age: 68 years; range: 38-91).

Inv(3)(q21q26)/t(3;3)(q21;q26) is recognized as a distinctive entity of acute myeloid leukemia (AML) with recurrent genetic abnormalities of prognostic significance. It occurs in 1-2.5% of AML and is also observed in myelodysplastic syndromes and in the blastic phase of chronic myeloid leukemia. The molecular consequence of the inv(3)/t(3;3) rearrangements is the juxtaposition of the ribophorin I (RPN1) gene (located in band 3q21) with the ecotropic viral integration site 1 (EVI1) gene (located in band 3q26.2). Following conventional cytogenetics to determine the karyotype, fluorescent in situ hybridization (FISH) with a panel of bacterial artificial chromosome clones was used to map the breakpoints involved in 15 inv(3)/t(3;3). Inv(3) or t(3;3) was the sole karyotypic anomaly in 6 patients, while additional abnormalities were identified in the remaining 9 patients, including 4 with monosomy of chromosome7 (-7) or a deletion of its long arm (7q-). Breakpoints in band 3q21 were distributed in a 235 kb region centromeric to and including the RPN1 locus, while those in band 3q26.2 were scattered in a 900 kb region located on each side of and including the EVI1 locus. In contrast to most of the inversions and translocations associated with AML that lead to fusion genes, inv(3)/t(3;3) does not generate a chimeric gene, but rather induces gene overexpression. The wide dispersion of the breakpoints in bands 3q21 and 3q26 and the heterogeneity of the genomic consequences could explain why the mechanisms leading to leukemogenesis are still poorly understood. Therefore, it is important to further characterize these chromosomal abnormalities by FISH.

Chromosomal rearrangements involving the MLL gene have been associated with many different types of hematological malignancies. Fluorescent in situ hybridization with a panel of probes coupled with long distance inverse-PCR was used to identify chromosomal rearrangements involving the MLL gene. Between 1995 and 2010, 27 patients with an acute leukemia were found to have a fusion gene involving MLL. All seven ALL patients with B cell acute lymphoblastic leukemia were characterized by the MLL/AFF1 fusion gene resulting from a translocation (5 patients) or an insertion (2 patients). In the 19 AML patients with acute myeloblastic leukemia, 31.6% of all characterized MLL fusion genes were MLL/MLLT3, 21.1% MLL/ELL, 10.5% MLL/MLLT6 and 10.5% MLL/EPS15. Two patients had rare or undescribed fusion genes, MLL/KIAA0284 and MLL/FLNA. Seven patients (26%) had a complex chromosomal rearrangement (three-way translocations, insertions, deletions) involving the MLL gene. Splicing fusion genes were found in three patients, leading to a MLL/EPS15 fusion in two and a MLL/ELL fusion in a third patient. This study showed that fusion involving the MLL gene can be generated through various chromosomal rearrangements such as translocations, insertions and deletions, some being complex or cryptic. A systematic approach should be used in all cases of acute leukemia starting with FISH analyses using a commercially available MLL split signal probe. Then, the analysis has to be completed, if necessary, by further molecular cytogenetic and genomic PCR methods.

The development of the bacterial artificial chromosome (BAC) system was driven in part by the human genome project in order to construct genomic DNA libraries and physical maps for genomic sequencing. The availability of BAC clones has become a valuable tool for identifying cancer genes. We report here our experience in identifying genes located at breakpoints of chromosomal rearrangements and in defining the size and boundaries of deletions in hematological diseases. The methodology used in our laboratory consists of a three-step approach using conventional cytogenetics followed by FISH with commercial probes, then BAC clones. One limitation to the BAC system is that it can only accommodate inserts of up to 300 kb. As a consequence, analyzing the extent of deletions requires a large amount of material. Array comparative genomic hybridization (array-CGH) using a BAC/PAC system can be an alternative. However, this technique has limitations also, and it cannot be used to identify candidate genes at breakpoints of chromosomal rearrangements such as translocations, insertions, and inversions.

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International audience; We report twins for whom ultrasound examinations revealed a Turner syndrome in the female fetus and a normal male fetus. A selective pregnancy termination was decided on the female fetus with hydrops. The death of both twins called in question the chorionic diagnosis. Amniotic fluid cytogenetic analysis revealed a 45,X karyotype in the female twin and a 47,XYY karyotype in the male twin. Molecular cytogenetic analysis on genital and renal cells showed different levels of 45,X/47,XYY mosaicism in both twins; molecular analysis on the amniocytes showed monozygosity. Monozygotic twins with discordant sex are very rare. This study showed the difficult diagnosis and management of a monochorionic twin pregnancy with discordant fetal sex.

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The Philadelphia (Ph) chromosome, resulting from a t(9;22)(q34;q11), is one of the most frequent chromosomal abnormalities observed among patients with acute lymphoblastic leukemia (ALL). Main of study: To analyze the distribution of Ph chromosome-positive ALL patients.Conventional cytogenetic analysis was performed on bone marrow cells at the time of diagnosis and/or relapse of 208 patients shown to have B-cell ALL. Fluorescent in situ hybridization studies using probe LSI BCR-ABL dual ES color (Abbott, Rungis, France) and other types of probes were performed on the available cytogenetic pellets.Thirty-three Ph chromosome-positive ALL patients were identified between 1981 and 2008. The Ph chromosome was present in 39.7% of the patients older than 25 years, but in only 4.3% of the patients younger than 15 years. A pseudodiploid karyotype was found in 68.75% of the patients and hypodiploidy in a further 15.6% of the patients. FISH studies revealed the breakpoint to be located in the major breakpoint cluster region in 20% of the patients and in the minor in the remaining 80% of the patients. Complex rearrangements of the derivative chromosomes 9 or 22 were identified in four patients, including a complex Ph translocation, t(9;22;X).Ph chromosome-positive ALL patients show cytogenetic characteristics that differ from those of other ALL patients.

We report the case of a 74-year-old man who sought care for de novo myelodysplastic syndrome (RAEB-1). Conventional cytogenetic techniques showed a karyotype with two different deletions of the long arm of chromosome 5 distributed in three clones: 46,XY,del(1)(p34),del(5)(q14q23)[2]/46,XY,del(1)(p34),del(5)(q14q34)[10]/46,idem,inv(5)(q?11q?34)[7]. Precise characterization of the breakpoints, delineation of the deleted regions, identification of the complex intrachromosomal rearrangement of chromosome 5, and sequential accumulation of chromosomal abnormalities were elucidated by several fluorescence in situ hybridization analyses. We also assessed the clinical, biological, and cytogenetic evolution under lenalidomide treatment and after its interruption.

Dear Editor, Primary myelofibrosis (PMF) is a BCR-ABL-negative chronic myeloproliferative disorder. Chromosomal abnormalities are heterogeneous but deletion of the long arm of chromosome 20 (del(20q)) is a recurrent abnormality observed in 20–30% in PMF [1]. A variant of deletion 20q, an isochromosome of the long arm of chromosome 20 with loss of interstitial material (ider(20q)), has recently been described in myeloid hemopathy [2–6]. To our knowledge, a sole case of primary myelofibrosis with ider(20q) has been published [7]. Here, we report two further cases. Patient 1 is a 79-year-old-woman who presented with chronic leukoneutropenia. Physical examination revealed neither hepatosplenomegaly nor lymphadenopathy. Trephine biopsy sections showed reticulin and collagen fibrosis with decreased cellularity. In fibrous tissue, megakaryocytes were dysplastic; granulocytic and erythroid lineages were nonexistent. An abdominal ultrasonography revealed a splenomegaly of 15.5 cm. JAK2 mutation was present. A diagnosis of primary myelofibrosis was made. Six months later, no sign of clinical evolution was observed. During these 6 months, the patient benefited from clinical surveillance, with blood parameters remaining stable. Hepatosplenomegaly was found at physical examination of a 71 year-old-woman (patient 2). The bone marrow aspirate revealed reticulin fibrosis. The patient received Ann Hematol (2009) 88:1157–1159 DOI 10.1007/s00277-009-0753-3

Isochromosome of the long arm of chromosome 20 with loss of interstitial material [ider(20q)] is a variant of deletion of chromosome 20q and a rare abnormality in myelodysplastic syndrome (MDS). We studied seven cases with an ider(20q) in MDS. Fluorescence in situ hybridization (FISH) studies showed all proximal breakpoints to be consistently located in 20q11.21 band whereas distal breakpoints were variable. Amplification of HCK, TNFRSF6B and DIDO1 genes included in retained regions associated with loss of tumour suppressor genes in deleted regions could explain cell tumour progression and possibly the less favourable prognosis of ider(20q) compared with del(20q).

This 15-month boy was expressed at the cytogenetic laboratory because of psychomotor development delay. He was tall and had plagiocephaly, micrognathia, high nasal bridge, anteverted nostrils and pectus excavatum. A 46,XY,del(4)(p16.1p16.3) karyotype was found using high-resolution R-banding technique. FISH studies using the LSI Wolf-Hirschhorn dual color 4p16.3 and the TelVysion 4p probes showed no deletion. Using BACs, the distal breakpoint was located in 4p16.3, between RP11-165K4 and RP11-717M10 and the proximal breakpoint in 4p15.33, between RP11-74M11 and RP11-1J7; therefore, approximately 7.96 Mb of the short arm were deleted. The maternal karyotype showed the same deletion, but in a mosaic status. Two distinct phenotypes have been recognized on the basis of the chromosomal bands involved in 4p deletion: the Wolf-Hirschhorn syndrome (WHS) and a proximal 4p deletion syndrome (4p15.2-p15.32). Our observation confirms that the basic WHS phenotype maps distally to this region.