Somatic homozygous loss of SH2B3, and a non-Robertsonian translocation t(15;21)(q25.3;q22.1) with NTRK3 rearrangement, in an adolescent with progenitor B-cell acute lymphoblastic leukemia with the iAMP21.

Intrachromosomal amplification of chromosome 21 (iAMP21) occurs in ∼2% of B-cell acute lymphoblastic leukemia (ALL) and is considered to confer a poor prognosis. The relapse risk is associated with therapy intensity, suggesting that other somatic mutations may influence iAMP21-ALL prognosis. This abnormality is characterized by multiple copies of the RUNX1 gene in chromosome 21 and appears to arise through multiple breakage-fusion bridge cycles and chromothripsis. Rob(15;21) or a ring chromosome 21 have been associated with an increased risk for iAMP21-ALL, suggesting that constitutional genetic abnormalities may also drive leukemogenesis. Here we describe homozygous deletion of the SH2B3 gene, chromothripsis of chromosome 21, and a non-Robertsonian somatic t(15;21)(q25.3;q22.1) with NTRK3 gene rearrangement in an adolescent with iAMP21-B-ALL. Molecular cytogenetic studies detected iAMP21 with aCGH analysis revealing further genomic imbalances. The RT-qPCR analysis detected elevated expression levels of RUNX1 (68-fold) and reduced expression of CDK6 (0.057-fold). Studies with constitutive cells collected from mouth swabs showed that SH2B3 biallelic deletion was a somatic alteration occurring during clonal evolution. The identification of novel secondary genetic changes was valuable to discuss sporadic iAMP21 leukemogenic mechanisms. For the first time, we show a t(15;21)(q25.3;q22.1) with NTRK3 rearrangement in an adolescent with iAMP21-ALL.

Chromosomal breakpoints in a cohort of head and neck squamous cell carcinoma patients.

Head and neck squamous cell carcinoma (HNSCC) presents complex chromosomal rearrangements, however, the molecular mechanisms behind HNSCC development remain elusive. The identification of the recurrent chromosomal breakpoints could help to understand these mechanisms. Array-CGH was performed in HNSCC patients and the chromosomal breakpoints involved in gene amplification/loss were analyzed. Frequent breakpoints were clustered in chromosomes 12p, 8p, 3q, 14q, 6p, 4q, Xq and 8q. Chromosomes 6, 14, 3, 8 and X exhibited higher susceptibility to have breaks than other chromosomes. We observed that low copy repeat DNA sequences are localized at or flanking breakpoint sites, ranging from 0 to 200 bp. LINES, SINES and Simple Repeats were the most frequent repeat elements identified in these regions. We conclude that in our cohort specific peri-centromeric and telomeric regions were frequently involved in breakpoints, being the presence of low copy repeats elements one of the explanations for the common rearrangement events observed.

A Multicentric Brazilian Investigative Study of Copy Number Variations in Patients with Congenital Anomalies and Intellectual Disability.

Genomic imbalances are the most common cause of congenital anomalies (CA) and intellectual disability (ID). The aims of this study were to identify copy number variations (CNVs) in 416 patients with CA and ID from 5 different genetics centers within 4 different states by using the Multiplex Ligation-dependent Probe Amplification (MLPA) technique and to apply the chromosomal microarray (CMA) methodology in selected cases. The samples were analyzed by MLPA kits P064, P036, P070 and P250. Positive results were found in 97/416 (23.3%) patients. CMA was applied in 14 selected cases. In 6/14 (42.85%) patients, CMA detected other copy number variations not detected by the MLPA studies. Although CMA is indispensable for genotype refinement, the technique is still unfeasible in some countries as a routine analysis due to economic and technical limitations. In these cases, clinical evaluation followed by karyotyping and MLPA analysis is a helpful and affordable solution for diagnostic purposes.

Genetic relationship between the Nordestino horse and national and international horse breeds.

Knowledge of genetic diversity and relationships between breeds is very important for conservation programs. Hair samples were collected from 393 individual Nordestino horses and genotyped using 14 microsatellite markers in order to investigate the genetic relationship between this breed and 66 international horse breeds. There was high allelic diversity and inbreeding coefficient within population values were not significant, which was probably due to crossbreeding. Despite the Nordestino horse population being in Hardy-Weinberg equilibrium, a global deficit of heterozygotes was observed. This may represent evidence of repeated use of the same stallions for breeding, which is consistent with the high number of castrated males found. Campolina, Mangalarga Marchador, and Mangalarga were the Brazilian horse breeds most closely related to the Nordestino horse, which is a reflection of recent introgressions. Among Iberian horse breeds, the Sorraia breed appears to have had an important influence on the genetics of the Nordestino horse. Those results provide important information that can guide future conservation programs.

Potential markers of cisplatin treatment response unveiled by NMR metabolomics of human lung cells.

In this work, (1)H high resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy was used to characterize the variations in the metabolome (small metabolites and mobile lipids) of A549 human lung cells in response to exposure to the alkylating drug cisplatin. Multivariate analysis and signal integration of spectral data were carried out to unveil exposure-induced effects and follow their time course. Parallel and strongly correlated increases in lipids (particularly unsaturated triglycerides) and nucleotide sugars (particularly uridine diphosphate N-acetylglucosamine) were found in cisplatin-treated cells, highlighting these compounds as potential biomarkers of treatment response. Other significant changes upon drug exposure comprised an increase in sorbitol and decreases in niacinamide and several amino acids (glutamine, alanine, lysine, methionine, citrulline, phenylalanine and tyrosine). These results show that in vitro NMR metabolomics is a powerful tool for detecting variations in a range of intracellular compounds upon drug exposure, thus offering the possibility of identifying candidate metabolite markers for in vivo monitoring of tumor responsiveness to treatment.

Molecular cytogenetic characterization of two cases with de novo small mosaic supernumerary marker chromosomes derived from chromosome 16: towards a genotype/phenotype correlation.

Small supernumerary marker chromosomes (sSMC) derived from chromosome 16 are rare and, so far, it is not yet clear which regions of chromosome 16 are critical and have clinical consequences. We have characterized two cases with a ring-shaped sSMC derived from chromosome 16. In case A the sSMC was encountered prenatally and was characterized using centromeric fluorescence in situ hybridization (FISH) probes, subcentromere-specific multicolor FISH (subcenM-FISH), reverse FISH and array-CGH, using a full-tiling BAC array specific for chromosome 16. Case B is a postnatal case and the sSMC was characterized by centromeric FISH probes and subcenM-FISH. Our results, using molecular cytogenetics, showed that both sSMC were derived from chromosome 16, resulting in a de novo mosaic partial trisomy of chromosome 16, involving euchromatic material from 16q. Array painting, in case A, allowed the localization of the sSMC breakpoints, revealing that the sSMC comprised the 33.43-47.02 Mb region of chromosome 16 (16p11.2 to 16q12.1), a region known to harbor some protein-coding genes. In general, the phenotypic consequences of a de novo marker chromosome are difficult to assess. Molecular cytogenetics techniques are a valuable tool for the accurate identification of the origin and content of marker chromosomes, contributing to a more informed prenatal counseling and patient follow-up. Besides multicolor FISH approaches, array painting, combining microdissection and array-CGH, is very useful for mapping size and breakpoints of marker chromosomes, since sSMC are often only present in a small percentage of cells.

First prenatally detected small supernumerary neocentromeric derivative chromosome 13 resulting in a non-mosaic partial tetrasomy 13q.

Neocentromeres are functional centromeres located in non-centromeric euchromatic regions of chromosomes. The formation of neocentromeres results in conferring mitotic stability to chromosome fragments that do not contain centromeric alpha satellite DNA. We present a report of a prenatal diagnosis referred to cytogenetic studies due to ultrasound malformations such as large cisterna magna, no renal differentiation, hypotelorism and ventriculomegaly. Cytogenetic analysis of GTG-banded chromosomes from amniotic fluid cells and fetal blood cells revealed a de novo small supernumerary marker chromosome. Molecular cytogenetic studies using fluorescence in situ hybridization and comparative genomic hybridization showed this marker to be an inverted duplication of the distal portion of chromosome 13q which did not contain detectable alpha satellite DNA. The neocentromeric constriction was located at band 13q31. The presence of a functional neocentromere on this marker chromosome was confirmed by immunofluorescence with antibodies to centromere protein-C. The anatomopathologic study revealed a female fetus with facial dysmorphisms, low set ears and renal dysplasia. Ten small supernumerary neocentromeric chromosomes originating from the distal region of chromosome 13q have been reported to date. There are only three additional cases described with the location of the neocentromere in band 13q31. This is the first reported case detected prenatally.

Sutura do coto duodenal em um e dois planos. Resistencia a insuflacao gasosa. Estudo experimental. / Duonenal stump suture in one and two layers.Experimental study

Visando o estudo do fechamento do coto duodenal, efetuou-se gastrectomia a BII, em 48 caes, que foram distribuidos igualmente em dois planos. No grupo 1 realizou-se a sutura do coto em um plano extramucoso e no grupo 2 em dois planos (total eseromuscular). Os animais de ambos o grupos foram distribuidos em seis subgrupos (com quatro unidades cada) correspondentes aos dias de sacrificio que foram o 1o., 4o., 7o., 14o., 21o. e 28. dia pos-operatorio. Foram analisados comparativamente os resultados da medida da resistencia tensil a distensao gasosa dos cotos duodenais. Este estudo mostrou resistencia tensil semelhante nos dois grupos estudados.