Meiotic Segregation of an Isodicentric Derived from Chromosome 15 in Sperm of a Patient with Mosaic Karyotype: Case Report and Review of the Literature.

Small supernumerary marker chromosomes (sSMCs) are defined as structurally abnormal chromosomes that are difficult to identify by conventional cytogenetic techniques. sSMCs are 3.75 times more common in infertile men than in the general population. This study aimed at characterizing a supernumerary marker chromosome in a nonconsanguineous infertile couple and analyzing its meiotic segregation in sperm by multicolor FISH. The male partner's karyotype was mos 47,XY,+idic(15)(pter→q11.1::q11.1→pter)[6]/46,XY[24].ish idic(15)(NOR+,D15Z3+,SNRPN-,D15Z3+,NOR+). In triple FISH using CEP 15, BAC 15, and BAC 21 probes, 4,227 spermatozoa of the patient were analyzed, and the sSMC was detected in only 0.66% of spermatozoa. In triple FISH employing CEP X, CEP Y, and BAC 18 probes, 2,008 spermatozoa of the patient were analyzed. The frequency of disomic and diploid sperm was not significantly different from control donors. To our knowledge, segregation of an sSMC 15 has been reported in only 9 males with non-mosaic karyotypes. These studies described rates of spermatozoa with sSMC 15 ranging from 6.23% to more than 50%. In this work, we report the first meiotic segregation analysis of a chromosome 15-derived sSMC in spermatozoa of a patient with a mosaic karyotype. The low rate of spermatozoa with sSMC detected is concordant with the low proportion of abnormal cells in our patient's lymphocytes. Moreover, the risk of interference of this sSMC with other chromosomes seems minimal. Genetic counseling was recommended given that the risk of chromosomal imbalance in the fetus linked to paternal sSMC was very low. Finally, a healthy boy was born after a natural pregnancy.

Acute myeloid leukaemia (FAB AML-M4Eo) with cryptic insertion of cbfb resulting in cbfb-Myh11 fusion.

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.

Breakpoint heterogeneity in (2;3)(p15-23;q26) translocations involving EVI1 in myeloid hemopathies.

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.

MACS-annexin V cell sorting of semen samples with high TUNEL values decreases the concentration of cells with abnormal chromosomal content: a pilot study.

We question whether, in men with an abnormal rate of sperm DNA fragmentation, the magnetic-activated cell sorting (MACS) could select spermatozoa with lower rates of DNA fragmentation as well as spermatozoa with unbalanced chromosome content. Cryopreserved spermatozoa from six males were separated into nonapoptotic and apoptotic populations. We determined the percentages of spermatozoa with (i) externalization of phosphatidylserine (EPS) by annexin V-Fluorescein isothiocyanate (FITC) labeling, (ii) DNA fragmentation by TdT-mediated-dUTP nick-end labeling (TUNEL), and (iii) numerical abnormalities for chromosomes X, Y, 13, 18, and 21 by fluorescence in situ hybridization (FISH), on the whole ejaculate and selected spermatozoa in the same patient. Compared to the nonapoptotic fraction, the apoptotic fraction statistically showed a higher number of spermatozoa with EPS, with DNA fragmentation, and with numerical chromosomal abnormalities. Compared to the whole ejaculate, we found a significant decrease in the percentage of spermatozoa with EPS and decrease tendencies of the DNA fragmentation rate and the sum of disomy levels in the nonapoptotic fraction. Conversely, we observed statistically significant higher rates of these three parameters in the apoptotic fraction. MACS may help to select spermatozoa with lower rates of DNA fragmentation and unbalanced chromosome content in men with abnormal rates of sperm DNA fragmentation.

Immunoglobulin gene translocations in chronic lymphocytic leukemia: A report of 35 patients and review of the literature.

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.

Double Inv(3)(q21q26), a rare but recurrent chromosomal abnormality in myeloid hemopathies.

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.

Characterization and meiotic segregation of a supernumerary marker chromosome in sperm of infertile males: case report and literature review.

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.

Conventional cytogenetics and breakpoint distribution by fluorescent in situ hybridization in patients with malignant hemopathies associated with inv(3)(q21;q26) and t(3;3)(q21;q26).

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.

Interphase FISH does not improve the detection of DEL(5q) and DEL(20q) in myelodysplastic syndromes.

Cytogenetic abnormalities identified by conventional cytogenetics (CC) have important prognostic and therapeutic roles in myelodysplastic syndromes (MDS). Fluorescence in situ hybridization (FISH) complements CC since it is able to evaluate large numbers of interphase and metaphase nuclei. The question has been raised as to whether interphase FISH in addition to CC is able to imprive the level of detection of del(5q) and del(20q) in MDS. This study performed interphase FISH with 5q and 20q probes in a series of 158 MDS patients with a normal karyotype. No hidden del(5q) or del(20q) was detected. A review of the literature identified 20 patients (1.96%) of 1018 patients (including the current series) and 3 (0.91%) of 331 patients to have a del(5q) or del(20q). Therefore, interphase FISH adds little, if any, improvement to the probability of detecting these deletions. However, interphase FISH is recommended in patients with no cell growth or when fewer than 20 metaphases are available for CC analysis.

Isochromosome 5p and related anomalies: a novel recurrent chromosome abnormality in myeloid disorders.

Loss of material from chromosome arm 5q is a common finding in patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). Fluorescence in situ hybridization with a panel of different types of probes, used as a complement to conventional cytogenetics, revealed that 7 of 148 patients (4.7%) with abnormalities of chromosome 5 had an i(5)(p10), an idic(5)(q11), or a structurally rearranged i(5)(p10). Three patients had MDS and four had AML. Six of the patients were female, and one was male; age at diagnosis ranged from 56 to 85 years. All patients but one had a complex karyotype. Isochromosome of the short arm of chromosome 5 and its related abnormalities such as idic(5)(q11) and structurally rearranged i(5)(p10) are rare but recurrent abnormalities; their identification requires a combination of conventional and molecular cytogenetic techniques. The biological and clinical significance cannot yet be assessed, not only because too few cases have been described but also because these abnormalities are usually part of a complex karyotype.

Molecular cytogenetic analysis by genomic hybridization to determine the cause of recurrent miscarriage.

OBJECTIVE: To characterize a t(2;6) by array-based comparative genomic hybridization (array-CGH) in a couple with recurrent miscarriage, to analyze the meiotic segregation of the t(2;6), and to discuss couple specific care-taking modality before intracytoplasmic sperm injection. DESIGN: Case report. SETTING: INSERM U613 in Brest, France. PATIENT(S): Couple consulting for infertility. INTERVENTION(S): Array-CGH to characterize a t(2;6) and fluorescence in situ hybridization (FISH) to analyze the meiotic segregation were performed. MAIN OUTCOME MEASURE(S): Array-CGH, FISH with a panel of bacterial artificial chromosome clones and commercial probes. RESULT(S): Analyses from peripheral blood lymphocytes identified a t(2;6)(q35;q24) unbalanced reciprocal translocation with microdeletions on the der(2) and the der(6). FISH on spermatozoa found that the frequency of normal (23,X or 23,Y) or "translocation-deletions" (23,X,der(2),der(6) or 23,Y,der(2),der(6)) spermatozoa was 41.10%. CONCLUSION(S): For our 46,XY,t(2;6)(q35;q24) carrier, more than 50% of the spermatozoa are chromosomally unbalanced. Moreover, FISH does not permit a distinction between normal and "translocation-deletion" phenotypes. So, in the possibility of preimplantation genetic diagnosis, is it necessary to select the normal embryos to the detriment of those translocation-deletions carriers? The pathogenicity of these microdeletions not been proved. Because the family history was oriented toward a variation of genetic equipment without phenotypic consequences, the couple decided not to make a selection between the normal embryos and the translocation-deletion carrier embryos.

Three rearrangements of chromosome 5 in a patient with myelodysplastic syndrome: an atypical deletion 5q, a complex intrachromosomal rearrangement of chromosome 5, and a paracentric inversion of chromosome 5.

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.

Del(5q) and MLL amplification in homogeneously staining region in acute myeloblastic leukemia: a recurrent cytogenetic association.

We report here a 71 year-old female presenting with acute myeloblastic leukemia (FAB-M1) after treatment of essential thrombocythemia with Vercyte. Conventional cytogenetic techniques showed a complex karyotype, 44,XX,-5,-7,-11,add(11)(q23),-14,+mar,+r. The use of several fluorescent in situ hybridizations (FISH) lead to the identification of these complex rearrangements. The marker was found to be tricentric, with pericentromeric material of chromosome 7 inserted in the short arm of chromosome 5, resulting in monosomy 5q and 7q. The derivative chromosome 11 was dicentric and had subtelomeric sequences of 11p on both ends; several copies of the MLL gene were located in two different regions separated by a centromere of chromosome 11. Twenty-one cases, including ours, of myelodysplastic syndromes and acute myelogenous leukemia with MLL amplification present in hsr or dmin were found in the literature. Most of these patients shared some characteristics: they were old, they had de novo acute myeloid leukemia (AML) with a complex karyotype and a short survival, 90% of them having also a del(5q). Therefore, the simultaneous presence of MLL amplification and del(5q) appears to be a nonrandom association that could be the signature of AML in elderly patients with a poor prognosis.