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Translocation (8;14)(q24;q32) as the sole cytogenetic abnormality in B-cell prolymphocytic leukemia.

B-cell prolymphocytic leukemia is a relatively rare lymphoproliferative disorder. No specific cytogenetic abnormality has yet been associated with it. The most common translocation reported in patients with this disease is t(11;14)(q13;q32). We describe the case of a patient with B-cell prolymphocytic leukemia and a hitherto unreported genetic translocation (8;14)(q24;q32) as the sole genetic abnormality, classically seen in patients with B-cell acute lymphoblastic leukemia/Burkitt lymphoma. This patient presented with an asymptomatic leukocytosis and splenomegaly. Her marrow showed lymphoid hyperplasia, with immunophenotyping consistent with prolymphocytic leukemia; however, t(8;14)(q24;q32) was the only cytogenetic aberration with both standard karyotyping and fluorescence in situ hybridization analysis.

Aged↗

The role for preimplantation genetic diagnosis in balanced translocation carriers.

OBJECTIVE: Preimplantation genetic diagnosis is an established technique that provides an alternative to prenatal diagnosis for patients who are at risk of transmitting a serious genetic disorder to their offspring. Preimplantation genetic diagnosis has been used for couples who have been at risk for having offspring with single gene or X-linked disorders and for screening for common age-related aneuploidy and in couples who themselves carry balanced chromosomal rearrangements. The aim of this study was to summarize our experience using preimplantation genetic diagnosis after the identification of a parental balanced translocation, specifically as it relates to the number of embryos that are suitable for transfer after preimplantation genetic diagnosis for a known translocation and aneuploidy screening. STUDY DESIGN: This is a retrospective review of data from a single center that involved 6 couples that initiated the process of preimplantation genetic diagnosis for translocation and aneuploidy screening by fluorescent in situ hybridization. RESULTS: A total of 65 embryos were obtained, of which 56 embryos (86%) were suitable for fluorescent in situ hybridization analysis. After fluorescent in situ hybridization, 1 embryo was diagnosed as normal or balanced (1.7%). Forty-three embryos (76.8%) were unbalanced for the translocation; 8 embryos (14.3%) were aneuploid, and 4 embryos (7.1%) were uninformative. There were no clinical pregnancies. CONCLUSION: In our experience, there are very few embryos that are available for transfer from these patients after translocation and aneuploidy screening because of multiple unbalanced segregation products and a high rate of aneuploidy. Factors that contributed to this may be related to which parent carries the translocation, methods that were used for in vitro fertilization, and advanced maternal age. Although preimplantation genetic diagnosis for translocation carriers theoretically can enhance the pregnancy rate for a couple, there are limitations. This information should be shared with couples who are contemplating preimplantation genetic diagnosis for translocation, and the options of sperm or egg donor should be considered.

Adult↗

Predictive value of sperm fluorescence in situ hybridization analysis on the outcome of preimplantation genetic diagnosis for translocations.

OBJECTIVE: To determine whether the proportion of abnormal sperm is predictive of the proportion of abnormal embryos from couples in which the males are translocation carriers. DESIGN: Controlled clinical study. SETTINGS: Private in vitro fertilization (IVF) center. PATIENT(S): Eleven cases of reciprocal translocation male carriers. INTERVENTION(S): Blood sample and sperm sample collection from each male partner. Embryo biopsy of the embryos produced in each cycle. MAIN OUTCOME MEASURE(S): Fluorescence in situ hybridization on lymphocyte slides to characterize each translocation case, then fluorescent in situ hybridization (FISH) with specific probes for each of the sperm samples. Preimplantation genetic diagnosis of the translocations in the 11 cases. RESULTS: A correlation was found between the percentage of abnormal gametes and the percentage of abnormal embryos, and a predictive equation is proposed for this relationship: A = -55 + (1.9 x B), where A is the percentage of abnormal embryos and B the percentage of abnormal sperm. CONCLUSION(S): The predictive value of the sperm analysis was established. Patients with 65% or less chromosomally abnormal sperm have a good chance at conceiving; patients with higher rates would need to produce 10 or more good quality embryos to have reasonable chances of conceiving.

Female↗

Chromosome-length polymorphism in fungi.

The examination of fungal chromosomes by pulsed-field gel electrophoresis has revealed that length polymorphism is widespread in both sexual and asexual species. This review summarizes characteristics of fungal chromosome-length polymorphism and possible mitotic and meiotic mechanisms of chromosome length change. Most fungal chromosome-length polymorphisms are currently uncharacterized with respect to content and origin. However, it is clear that long tandem repeats, such as tracts of rRNA genes, are frequently variable in length and that other chromosomal rearrangements are suppressed during normal mitotic growth. Dispensable chromosomes and dispensable chromosome regions, which have been well documented for some fungi, also contribute to the variability of the fungal karyotype. For sexual species, meiotic recombination increases the overall karyotypic variability in a population while suppressing genetic translocations. The range of karyotypes observed in fungi indicates that many karyotypic changes may be genetically neutral, at least under some conditions. In addition, new linkage combinations of genes may also be advantageous in allowing adaptation of fungi to new environments.

Chromosomes, Fungal↗

Rapid quantitative detection of TEL-AML1 fusion transcripts in pediatric acute lymphoblastic leukemia by real-time reverse transcription polymerase chain reaction using fluorescently labeled probes.

BACKGROUND AND OBJECTIVES: We report a new real-time reverse transcription polymerase chain reaction (RT-PCR) method for quantification of TEL-AML1 transcripts. The method is based on hybridization probe (HybProbe) chemistry applied in LightCycler equipment. The study group comprised 44 successive cases of pediatric acute lymphoblastic leukemia (P-ALL). DESIGN AND METHODS: The quantitative estimation of TEL-AML1 transcripts was performed in 10 P-ALL TEL-AML1-positive patients. The PCR was performed in capillary tubes in 10 microL final volumes using two sets of primers: M1, which detects the long (L-form) and short (S-form) transcripts, and M2, specific for the L-form. The fluorescently labeled HybProbes (TEL 3FL and TEL 5LC) hybridize to the TEL region. TEL-AML1 expression was normalized relative to the levels of AML1 transcripts. Standard curves were prepared using serial dilutions of plasmids with TEL-AML1 or AML1 inserts. RESULTS: The sensitivity attained allowed the detection of TEL-AML1 transcripts at a 10-4 dilution of a cDNA sample from a patient at diagnosis. The within-assay coefficient of variation (CV) for TEL-AML1 was 7.0% and the between-assay CV was 13%. Levels of TEL-AML1 transcript and the TEL-AML1/AML1 ratio decreased by more than four log units (p <0.001) during or after the course of initial treatment. Most of the patients who achieved complete remission after 5-6 months of initial treatment were TEL-AML1 negative, although some positive samples with negligible amounts of TEL-AML1 transcripts were still detected. INTERPRETATION AND CONCLUSIONS: This method has the sensitivity and reliability required to monitor the presence of minimal residual disease, and could be a powerful tool in monitoring the efficacy of the response to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

Allozyme genetics in permanent translocation heterozygotes of the Oenothera biennis complex.

Allozyme inheritance and transmission genetics of 11 enzyme systems were determined in the permanent translocation heterozygotes Oenothera biennis, Oe. strigosa, and Oe. parviflora. Electrophoretic variation was examined first among 164 strains of structural heterozygotes. Allelic configurations were then judged from inheritance patterns in reciprocal F1 hybrids between each of 22 ring-forming strains and tester strains of the related bivalent-formers, Oe. hookeri and Oe. grandiflora. Allozymes are inherited as codominant markers, and, as dictated by the genetic system, within a strain individual allelic variants are generally transmitted through only one germ line. Of the 20 loci resolved, only eight are polymorphic in any species, and, within species, generally only two alleles are present at each polymorphic locus. Despite the relatively meager allelic array, each of the 22 strains whose chromosome complexes were characterized is genotypically unique. Generally, within taxa, alpha (egg) and beta (sperm) complexes differ in allele frequency at several polymorphic loci. Such variability is correlated with differences in the phylogenetic origins of complexes and not with differences in segmental arrangement within a group of related complexes.

Alleles↗

Complex variant Philadelphia translocation involving the short arm of chromosome 9 in a case of chronic myeloid leukemia.

Here we describe how we detected the BCR/ABL fusion gene on the short arm of der(9) combining classical GTG banding and Fluorescence In Situ Hybridization (FISH) in a case of chronic myeloid leukemia (CML). To our knowledge, variant translocations involving the short arm of chromosome 9, in literature, are almost rare in chronic myeloid leukemia. It is not clear if this complex genetic translocation represents clonal evolution or a unique, initial presentation variant of the Philadelphia chromosome (Ph).

Adult↗

River capture, range expansion, and cladogenesis: the genetic signature of freshwater vicariance.

River capture is potentially a key geomorphological driver of range expansion and cladogenesis in freshwater-limited taxa. While previous studies of freshwater fish, in particular, have indicated strong relationships between historical river connections and phylogeographic pattern, their analyses have been restricted to single taxa and geological hypotheses were typically constructed a posteriori. Here we assess the broader significance of river capture among taxa by testing multiple species for the genetic signature of a recent river capture event in New Zealand. During the Quaternary an upper tributary of the Clarence River system was diverted into the headwaters of the Wairau River catchment. Mitochondrial DNA (control region and cytochrome b) sequencing of two native galaxiid fishes (Galaxias vulgaris and Galaxias divergens) supports headwater exchange: populations from the Clarence and Wairau Rivers are closely related sister-groups, whereas samples from the geographically intermediate Awatere River are genetically divergent. The upland bully Gobiomorphus breviceps (Eleotridae), in contrast, lacks a genetic signature of the capture event. We hypothesize that there is an increased likelihood of observing genetic signatures from river capture events when they facilitate range expansion, as is inferred for the two galaxiid taxa studied here. When river capture merely translocates genetic lineages among established populations, by contrast, we suggest that the genetic signature of capture is less likely to be retained, as might be inferred for G. breviceps. Rates of molecular evolution calibrated against this recent event were elevated relative to traditional estimates, consistent with the contribution of polymorphisms to branch lengths at shallow phylogenetic levels prior to fixation by purifying selection and drift.

Animals↗

[Genetic analysis of translocation of chromosome t(4;9) in a child with rare chromosome abnormality].

A 10-month-old boy suspected of genetic abnormality was admitted for fever and coughing. Routine G-banding chromosome analysis of the peripheral blood lymphocytes and hereditary pattern analysis on the basis of the karyotypes and disease history revealed that the karyotype of the boy's mother was 46, XX,t(4;9)(q31;p24), and that of the boy was XY,der(9)t(4;9)(q31;p24)mat. The mother was identified as a carrier of balanced translocation of the chromosome who gave the abnormal chromosome 9 to her son, and she had only a chance of 1:18 to have a normal offspring. This case reiterates the importance of antemarital examination and prenatal diagnosis for preventing chromosomal diseases.

Abnormalities, Multiple↗

Ecological analysis of field trials conducted to assess the potential of sex-linked translocation strains for genetic control of the Australian sheep blowfly, Lucilia cuprina (Wiedemann).

Field trials were conducted with translocation/eye colour (TE) strains of L. cuprina to measure the mating ability of the males under field conditions and assess their potential for suppressing sheep blowfly populations. Rates of increase in L. cuprina were highest in spring (3.9-9.1 per generation), consistently low during summer (0.1-0.6 per generation) and somewhat higher during autumn (1.1-3.4 per generation). The TE strains released had the potential to prevent population increases of this magnitude. Their failure to do so during these trials resulted from their low mating competitiveness (0.33) relative to that of field-reared males (1.0), inadequacy of the larval release method and the limited capacity of the experimental mass-rearing facility.

Animals↗

Hodgkin's disease, lymphomatoid papulosis, and cutaneous T-cell lymphoma derived from a common T-cell clone.

BACKGROUND: Lymphomatoid papulosis is a benign cutaneous eruption that in 10 to 20 percent of patients is associated with the development of lymphoma. The atypical cells of lymphomatoid papulosis histologically resemble the malignant cells of cutaneous T-cell lymphoma or the Reed-Sternberg cells of Hodgkin's disease. We studied a patient in whom lymphomatoid papulosis developed in 1971, Hodgkin's disease in 1975, and cutaneous T-cell lymphoma in 1985, to determine whether these diseases are clonally related. METHODS: The T-cell-receptor alpha-chain gene was cloned and sequenced from a cell line derived from the advanced-stage cutaneous T-cell lymphoma, and the polymerase chain reaction was used to search for this rearrangement of the alpha-chain gene in tissues obtained earlier that were affected by Hodgkin's disease or lymphomatoid papulosis. RESULTS: The tumor-specific rearrangement of the alpha-chain gene was detected in the patient's earlier tissues affected by lymphomatoid papulosis and Hodgkin's disease, but not in control tissue, including uninvolved tissues from the staging laparotomy for Hodgkin's disease. Cytogenetic studies revealed a translocation, t(8;9)(p22;p24), in cutaneous T-cell lymphoma lines and in a dermatopathic lymph node removed two years before the clinical onset of the cutaneous T-cell lymphoma. Immunohistochemical findings were consistent with an activated T-cell phenotype for the atypical cells of lymphomatoid papulosis, the Reed-Sternberg cells of Hodgkin's disease, and the malignant cells of the T-cell lymphoma. CONCLUSIONS: Lymphomatoid papulosis, Hodgkin's disease, and cutaneous T-cell lymphoma can be derived from a single T-cell clone. A t(8;9) genetic translocation may be involved in the pathogenesis of lymphomatoid papulosis or its progression to malignant disease.

Adult↗

Rapid detection of genetic mutations using the chemiluminescent hybridization protection assay (HPA): overview and comparison with other methods.

The detection of genetic mutations is of paramount importance for the study, diagnosis, and treatment of human genetic disease. Methods of detection generally fall into one of two categories: those to scan for unknown mutations and those to detect known mutations. This review focuses on methods for the detection of known mutations. The hybridization protection assay (HPA) is described in detail. The HPA method utilizes short oligonucleotide probes covalently labeled with a highly chemiluminescent acridinium ester (AE). The assay format is completely homogeneous, requiring no physical separation steps, and can rapidly and sensitively detect all single-base mismatches as well as multiple mismatches, insertions, deletions, and genetic translocations. When very low copy number targets are assayed, HPA is coupled with transcription-mediated amplification (TMA), an isothermal method that amplifies DNA or RNA targets. Other methods that are described for the detection of known mutations include hybridization with sequence-specific oligonucleotides, hybridization to oligonucleotide arrays, allele-specific amplification, ligase-mediated detection, primer extension, and restriction fragment analysis. The advantages and limitations of each of these methods are discussed. Methods to scan for unknown mutations are briefly described.

Base Pair Mismatch↗