Genomic variations in patients with myelodysplastic syndrome and karyotypes without numerical or structural changes.

Myelodysplastic syndrome (MDS) is an onco-hematologic disease with distinct levels of peripheral blood cytopenias, dysplasias in cell differentiation and various forms of chromosomal and cytogenomic alterations. In this study, the Chromosomal Microarray Analysis (CMA) was performed in patients with primary MDS without numerical and/or structural chromosomal alterations in karyotypes. A total of 17 patients was evaluated by GTG banding and eight patients showed no numerical and/or structural alterations. Then, the CMA was carried out and identified gains and losses CNVs and long continuous stretches of homozygosity (LCSHs). They were mapped on chromosomes 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 14, 16, 17, 18, 19, 20, 21, X, and Y. Ninety-one genes that have already been implicated in molecular pathways important for cell viability were selected and in-silico expression analyses demonstrated 28 genes differentially expressed in mesenchymal stromal cells of patients. Alterations in these genes may be related to the inactivation of suppressor genes or the activation of oncogenes contributing to the evolution and malignization of MDS. CMA provided additional information in patients without visible changes in the karyotype and our findings could contribute with additional information to improve the prognostic and personalized stratification for patients.

Molecular Characterization of Koolen De Vries Syndrome in Two Girls with Idiopathic Intellectual Disability from Central Brazil.

Koolen de Vries syndrome (KDVS; MIM 610443) is a genomic disorder caused by a recurrent microdeletion derived from nonallelic homologous recombination mediated by flanking segmental duplications. Clinical manifestations of this syndrome are characterized by intellectual disability, hypotonia, a friendly behavior, distinctive facial features, and epilepsy. Herein, we report a case of 2 girls who revealed global developmental delay, mild facial dysmorphisms, friendly behavior, and epileptic seizure with a de novo 17q21.31 microdeletion detected by chromosomal microarray analysis (CMA). Conventional cytogenetics analysis by GTG-banding showed a female karyotype 46,XX for both girls. CMA revealed a microdeletion spanning approximately 500 kb in 17q21.31 in both girls, encompassing the following genes: CRHR1, MGC57346, CRHR1-IT1, MAPT-AS1, SPPL2C, MAPT, MAPT-IT1, STH, and KANSL1. Haploinsufficiency of one or more of these genes within the deleted region is the most probable cause of the probands' phenotype and is responsible for the phenotype seen in KDVS. CMA is a powerful diagnostic tool and an effective method to identify the de novo 17q21.31 microdeletion associated with KDVS in our probands.

Applicability of gene expression profile of childhood acute lymphoblastic leukemia at diagnosis and at the end of the induction phase of chemotherapy at a cancer hospital in the state of Goiás (Brazil).

The present study compared the gene expression pattern of some previously described genes at the time of diagnosis and after induction chemotherapy for childhood acute lymphoblastic leukemia (ALL) in patients submitted to Brazilian Childhood Leukemia Treatment Group (GBTLI) ALL-99 Protocol. Samples were obtained at the time of diagnosis from 16 patients with ALL and on the 28th day of induction chemotherapy the bone marrow samples were obtained from 12 children. The genes expression profiles in diagnostic and induction samples were analyzed by array-based qPCR and then related to the clinical and biological prognostic factors. The results showed significant associations (p ≤ 0.05) between gender and immunophenotype, immunophenotype and age, immunophenotype and risk group, presence of CD10 and RUNX1 expression, risk group, and immunophenotype. A significant positive correlation was observed between the expression levels of BAX and BCL2. There was a significant difference (p = 0.008) between the gene expression pattern at the time of diagnosis and after induction chemotherapy. The expression pattern of these genes after the induction phase of treatment approached the expression profile of the control group, indicating a good induction response in children treated according to the GBTLI ALL-99 protocol. The findings of the current research could be routinely useful for clinical practice and could assist in the discovery phase of medical applications.

An easy procedure for cytogenetic analysis of aged chromosome preparations using FISH-WCP probes.

Fluorescence in-situ hybridization using whole chromosome probes (FISH-WCP) has become the methodology of choice of most cytogenetic laboratories. However, good hybridization results are often associated with sample quality, storage conditions, and the age of metaphase preparations. Particularly, aging metaphase preparations over a prolonged period of time has been considered a critical and limiting factor in FISH success. This study reports on the successful use of the FISH-WCP procedure to hybridize chromosome preparations that were aged for approximately 12 years. Biological samples consisted of 4 individuals accidentally exposed to cesium-137 in Goiânia (Brazil) in 1987 and 1 control individual. Metaphase spreads were obtained from conventionally PHA-stimulated T lymphocytes from peripheral blood. Aged slides underwent treatment with Carnoy's fixative for 16 h, followed by exposing the slides to water-bath vapour at 60 degrees C for 4 h. During analysis, chromosome type aberrations, including translocations, acentric fragments, and dicentrics were observed. The results suggested that it is possible to validate the use of FISH-WCP as a method of choice to study aged chromosome preparations, even if the slides were stored in undesirable conditions of temperature and humidity. Under these circumstances, the procedure could possibly be used as a potent tool in retrospective dosimetry.