A rare case of a boy with de novo microduplication at 5q35.2q35.3 from central Brazil.

Genomic disorders are genetic diseases that are caused by rearrangements of chromosomal material via deletions, duplications, and inversions of unique genomic segments at specific regions. Such rearrangements could result from recurrent non-allelic homologous recombination between low copy repeats. In cases where the breakpoints flank the low copy repeats, deletion of chromosomal segments is often followed by reciprocal duplication. Variations in genomic copy number manifest differently, with duplication and deletions of the same genomic region showing opposite phenotypes. Sotos syndrome is caused by alterations in the dosage of NSD1 on human chromosome 5 by either deletions or mutations, such as microdeletion of 5q35.2q35.3. In general, patients carrying reciprocal microduplication at 5q35.2q35.3 present no clinical phenotype or milder phenotype than do patients with microdeletion at the same locus. We report the first case of 5q35.2q35.3 microduplication encompassing NSD1 in a patient from central Brazil. We identified a genomic imbalance corresponding to a de novo 0.45 Mb microduplication at 5q35.2q35.3 by chromosomal microarray analysis and study of low-copy repeats. The proband had microduplication in the chromosomal region containing NSD1, which resulted in a Sotos syndrome reversed phenotype, and this duplication was associated with microcephaly, short stature, and developmental delay. Analysis of the genomic structure of the rearranged 5q35.2q35.3 chromosomal region revealed two major low-copy repeat families, which caused the recurrent rearrangements. Chromosomal microarray analysis is a potential tool to identify microrearrangements and guide medical diagnosis, which has to be followed by a non-directive genetic counseling approach to improve the quality of life of the patient.

CASE-REPORT Association between an ACAN gene variable number tandem repeat polymorphism and lumbar disc herniation: a case control study.

We investigated the association between an aggrecan gene (ACAN) polymorphism and lumbar disc herniation (LDH). This was a case-control study with quinquennial age and gender groups. The study comprised 119 men and women aged between 20 and 60 from Goiânia (Brazil). Of these, 39 were allocated to the case group (Ca) and 80 to the control group (Ct). We gathered sociodemographic and clinical data, and peripheral blood samples. DNA was isolated for genotyping the ACAN variable number tandem repeat (VNTR) via conventional polymerase chain reaction (PCR). Data were statistically analyzed using the chi-square test, multiple comparison analysis, the Student t-test, and odds ratios, with a level of significance set at 5% (P ≤ 0.05). The groups were homogenous in terms of sociodemographic, anthropometric, and life style variables. The allele score for the ACAN VNTR was significantly lower in volunteers with LDH; the A22 allele was significantly more prevalent in this same group; the Ca group presented greater frequency of short alleles A13-A25, whereas the Ct group presented a higher frequency of long alleles. However, this difference was not statistically significant. In both groups, the most common alleles were A28, A27, and A29, and the A26/A26 genotype was significantly more common in the Ca group. The results showed an association between short alleles and LDH among the investigated adults (Ca), corroborating the hypothesis that aggrecan with shorter repeat lengths can lead to a reduction in the physiological proteoglycan function of intervertebral disc hydration and, consequently, increased individual susceptibility to LDH.

Identification of trends in scientific publications related to genetic polymorphisms in gestational diabetes mellitus.

Gestational diabetes is a genetic multifactorial systemic disease that has been extensively studied. Consequently, there is a large volume of scientific literature pertaining to genes associated with gestational diabetes. The aim of this study was to characterize the main trends in scientific publications focusing on the associations between genetic polymorphisms and gestational diabetes mellitus (GDM). The related articles were extracted from Scopus using the key words "genetic polymorphism" and "gestational diabetes mellitus"; the collected data focused on various fields (medical, biochemical, etc.) and included papers published within December 2013. One hundred and eighty-three relevant articles published between 1987 and 2013 were identified; we observed a significantly increasing trend in the number of publications pertaining to GDM. A majority of the articles focused on the medical (59.9%), biochemical, and genetics and molecular biological (29.6%) aspects of the disease. The genes coding for transcription factor 7-like 2 and glucokinase (TCF7L2, 29% and GCK, 28%) were predominantly studied and reported. This study helped quantify the growth in research pertaining to GDM; researchers from the USA have published a majority of the publications related to GDM. Several candidate genes have been linked to diabetes; however, the specific gene locus responsible for GDM has not yet been identified. The results of this study could help determine the orientation of future research on genetic factors associated with GDM.

Molecular analysis of patients suspected of Fragile X Syndrome.

The aim of this study was to validate the molecular genetic diagnosis of patients suspected of Fragile X Syndrome (FXS) in the Laboratory of Human Cytogenetics and Molecular Genetics (LaGene) of the Department of Health of the State of Goiás, using polymerase chain reaction (PCR). Thirty-five patients referred by public health doctors to LaGene, indicating clinical diagnosis of FXS, were selected for this study. Two PCR analyses were performed using different primers, one for screening (PCR-T) and one for the detection of the pre-mutation (PCR-P). The products of both PCRs were subjected to polyacrylamide gel electrophoresis and then coloring. The visualization of amplicons was performed with the aid of an ultraviolet transilluminator. The diagnosis was confirmed in 88% of patients with PCR-T and 100% with PCR-P. The primer used in PCR-P was found to be more sensitive and specific, allowing to identify the mutation in the samples, generating a more conclusive case for FXS, noting that the PCR-T is also required for the pre-classification of patients. Generally, the PCR technique is cheaper and easier to handle; therefore, we suggest the implementation of PCR in the genetics laboratory of the State of Goiás (LaGene) for the diagnosis of FXS.

Postnatal diagnosis of constitutive ring chromosome 13 using both conventional and molecular cytogenetic approaches.

We describe the first postnatal diagnosis of a child from Central Brazil with de novo cytogenetic alterations in 13q showing malformations of the brain, eyes, distal limbs, and genitourinary tract, and severe intellectual disability. The karyotype was a constitutive 46,XX,r(13)[77]/45,XX,-13[17]/46,XX,idic r(13)[6]. Interphase and metaphase fluorescence in situ hybridization analyses also showed the absence of 13qter and the presence of 13q14.3 in the cells with r(13), and chromosome microarray analysis detected a 15.39 Mb deletion in chromosome region 13q32.3-q34. This study is intended as the registry of a rare case of chromosomal rearrangement involving chromosome 13 in Central Brazil. Further studies are needed to define whether genetic haploinsufficiency is associated with each major 13q deletion anomaly.

Lack of association between IL-10 -1082G/A polymorphism and chronic periodontal disease in adults.

Because of the complex interaction between periodontal pathogens and the host defense system, periodontitis is considered an inflammatory disorder of bacterial etiology that results in periodontal tissue damage. Genetic mechanisms may interfere with the gene expression of important inflammation mediators, modulating the immunologic response of an individual. In this study, we evaluated the single nucleotide polymorphism -1082G/A in the promoter region of interleukin-10 gene and its relationship with periodontal disease in Central Brazil. We included 36 cases classified according to disease severity (mild, moderate, or severe) and 30 controls. The allelic distribution of the cases was 16 (44%) AG, followed by 13 (36%) GG and 7 (20%) with the genotype AA. In the control group, 13 (43%) presented the genotype AG, 12 (40%) GG and 5 (17%) were classified as AA. The populations examined were in Hardy-Weinberg equilibrium. Analysis of allelic and genotypic frequencies revealed no casual relationship with the presence of genotype G or A and the development of periodontal disease in adults. The single nucleotide polymorphism -1082G/A of the interleukin-10 gene was not predictive of periodontal disease.

Cytogenetic damage in the buccal epithelium of Brazilian aviators occupationally exposed to agrochemicals.

The frequency of micronuclei in both buccal cells and peripheral blood lymphocytes is extensively used as a biomarker of chromosomal damage and genome stability in human populations. We examined whether prolonged exposure to complex mixtures of pesticides leads to an increase in cytogenetic damage. The exposed group comprised 50 agricultural aviators, mainly from Central and Southeast regions of Brazil, who had inhaled agrochemicals for more than 10 years without personal protection equipment; the control group consisted of 17 men from the same regions, without indication of exposure to pesticides, There were three times higher frequencies of micronuclei (P < 0.05) and 2.5 times higher frequencies of binucleated cells in the aviators when compared to controls. However, cytotoxic alterations such as broken eggs and karyorrhexis did not present statistically significant differences between the exposed and control groups. Therefore, diverse agrochemicals used to combat pests in agriculture possess genotoxic effects in the oral mucosa of the agricultural pilots, as showed in this study.