Search

This study investigates the role of floating plastics as integrative samplers of organic contaminants. To this end, plastics items were collected in two Western Mediterranean coastal areas: the Mar Menor lagoon, and the last transect of Ebro river. Floating plastics were identified and characterized by attenuated total reflection Fourier-transform infrared spectrometry. Then, organic contaminants were extracted from plastic items by ultrasonic extraction with methanol, and the concentrations of 168 regulated and emerging contaminants were analysed. These compounds were analysed by stir bar sorptive extraction coupled to gas chromatography-mass spectrometry (GC-MS), except for bisphenol analogues, which were analysed with a ultraperformance liquid chromatography pump coupled to a triple quadrupole mass spectrometer (UHPLC-MS/MS), and pharmaceutical compounds, determined by UPLC coupled to hybrid triple quadrupole-linear ion trap mass spectrometer (UPLC-MS/MS). All the contaminants groups considered were detected in the samples, being particularly relevant the contribution of plastic additives. The most frequently detected contaminants were UV-filters, PAHs, pharmaceuticals and synthetic musks. Apart from plasticizers, the individual contaminants octocrylene, homosalate, galaxolide, salycilic acid and ketoprofen were frequently detected in plastics items. The results pointed out to urban and touristic activities as the main sources of pollution in the coastal areas investigated. The utility of floating plastics as integrative samplers for the detection of organic contaminants in aquatic ecosystems has been demonstrated., Competing Interests: Declaration of competing interest Victor M. Leon reports financial support was provided by Spanish Inter-Ministerial Science and Technology Commission through the ‘PLAS-MED’ (CICYT, CTM2017-89701-C3) project and by the European Union through the European Regional Development Fund (ERDF); and by PHARMASEA (PCI2021-121933) project through EU Next Generation Fund (Plan de Recuperación, Transformación y Resiliencia). Maria del Mar Garcia-Pimentel reports financial support was provided by Spanish Ministry of Science, Innovation and Universities., (Copyright © 2023. Published by Elsevier B.V.)

Pharmaceuticals and microplastics constitute potential hazards in aquatic systems, but their combined effects and underlying toxicity mechanisms remain largely unknown. In this study, a simultaneous characterization of bioaccumulation, associated metabolomic alterations and potential recovery mechanisms was performed. Specifically, a bioassay on Mediterranean mussels (Mytilus galloprovincialis) was carried out with polyethylene microplastics (PE-MPLs, 1 mg/L) and citalopram or bezafibrate (500 ng/L). Single and co-exposure scenarios lasted 21 days, followed by a 7-day depuration period to assess their potential recovery. PE-MPLs delayed the bioaccumulation of citalopram (lower mean at 10 d: 447 compared to 770 ng/g dw under single exposure), although reaching similar tissue concentrations after 21 d. A more limited accumulation of bezafibrate was observed overall, regardless of PE-MPLs co-exposure (

Coastal ecosystems are particularly vulnerable to terrestrial inputs from human-impacted areas. The prevalence of wastewater treatment plants, unable to remove contaminants such as pharmaceuticals (PhACs), leads to their continuous input into the marine environment. In this paper, the seasonal occurrence of PhACs in a semi-confined coastal lagoon (the Mar Menor, south-eastern Spain) was studied during 2018 and 2019 by evaluating their presence in seawater and sediments, and their bioaccumulation in aquatic organisms. Temporal variation in the contamination levels was evaluated by comparison to a previous study carried out between 2010 and 2011 before the cessation of permanent discharges of treated wastewater into the lagoon. The impact of a flash flood event (September 2019) on PhACs pollution was also assessed. A total of seven compounds (out of 69 PhACs analysed) were found in seawater during 2018-2019, with a limited detection frequency (<33%) and concentrations (up to 11 ng/L of clarithromycin). Only carbamazepine was found in sediments (ND-1.2 ng/g dw), suggesting an improved environmental quality in comparison to 2010-2011 (when 24 and 13 compounds were detected in seawater and sediments, respectively). However, the biomonitoring of fish and molluscs showed a still remarkable accumulation of analgesic/anti-inflammatory drugs, lipid regulators, psychiatric drugs and β-blocking agents, albeit not higher than in 2010. The flash flood event from 2019 increased the prevalence of PhACs in the lagoon, compared to the 2018-2019 sampling campaigns, especially in the upper water layer. After the flash flood the antibiotics clarithromycin and sulfapyridine yielded the highest concentrations ever reported in the lagoon (297 and 145 ng/L, respectively), alongside azithromycin in 2011 (155 ng/L). Flash flood events associated with sewer overflows and soil mobilisation, which are expected to increase under climate change scenarios, should be considered when assessing the risks posed by pharmaceuticals to vulnerable aquatic ecosystems in the coastal areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Sarcopenia is a highly prevalent muscle dysfunction among older adults and is associated with adverse events. The periodic monitoring enables an early screening of patients at risk and control of the progression of muscle impairment. Wearable devices have been used as clinical support for sarcopenia detection. Therefore, this review aims to identify how wearable devices have been used to screen sarcopenia., Methods and Analyses: Searches will be conducted from August 2023 on PubMed, CINHAL, Embase, Web of Science and SciELO databases. We will include cross-sectional and/or baseline data from prospective studies reporting the use of wearable devices to investigate sarcopenia. Studies that discuss only the development of algorithms or applications for the assessment of sarcopenia or unavailable full texts will be excluded. The main reviewer will conduct the initial search and exclusion of duplicates, while two independent reviewers will select studies, extract data and assess the methodological quality using the Appraisal tool for Cross-sectional Studies., Ethics and Dissemination: No previous ethical approval is required for this review. The findings of this review will be submitted to a scientific journal and disclosed at international scientific conferences., Prospero Registration Number: CRD42022356040., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Gastric cancer is the fifth most common and fourth type to cause the highest mortality rates worldwide. The leading cause is related to Helicobacter pylori ( H. pylori ) infection. Unfortunately, current treatments have low success rates, highlighting the need for alternative treatments against carcinogenic agents, specifically H. pylori . Noteworthy, natural origin products contain pharmacologically active metabolites such as flavonoids, with potential antimicrobial applications. Objective: This article overviews flavonoid-rich extracts' biological and pharmacological activities. It focuses on using these substances against Helicobacter pylori infection to prevent gastric cancer. For this, PubMed and Science Direct databases were searched for studies that reported the activity of flavonoids against H. pylori , published within a 10-year time frame (2010 to August 2020). It resulted in 1,773 publications, of which 44 were selected according to the search criteria. The plant family primarily found in publications was Fabaceae (9.61%). Among the flavonoids identified after extraction, the most prevalent were quercetin (19.61%), catechin (13.72), epicatechin (11.76), and rutin (11.76). The potential mechanisms associated with anti- H. pylori activity to the extracts were: inhibition of urease, damage to genetic material, inhibition of protein synthesis, and adhesion of the microorganism to host cells. Conclusion: Plant extracts rich in flavonoids with anti- H. pylori potential proved to be a promising alternative therapy source, reinforcing the relevance of studies with natural products., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ivyna de Araújo Rêgo, Guedes Silvestre, Ferreira de Melo, Albino, Pimentel, Silva Costa Cruz, Silva Wurzba, Rodrigues, Goulart de Lima Damasceno and Cançado Castellano.)

Objectives: Intellectual Disability (ID) and Global Development Delay (GDD) are frequent reasons for referral to genetic services and although they present overlapping phenotypes concerning cognitive, motor, language, or social skills, they are not exactly synonymous. Aiming to better understand independent or shared mechanisms related to these conditions and to identify new candidate genes, we performed a highly stringent protein-protein interaction network based on genes previously related to ID/GDD in the Human Phenotype Ontology portal., Methods: ID/GDD genes were searched for reliable interactions through STRING and clustering analysis was applied to detect biological complexes through the MCL algorithm. Six coding hub genes ( TP53 , CDC42 , RAC1 , GNB1 , APP, and EP300 ) were recognised by the Cytoscape NetworkAnalyzer plugin, interacting with 1625 proteins not yet associated with ID or GDD. Genes encoding these proteins were explored by gene ontology, associated diseases, evolutionary conservation, and brain expression., Results: One hundred and seventy-two new putative genes playing a role in enriched processes/pathways previously related to ID and GDD were revealed, some of which were already postulated to be linked to ID/GDD in additional databases., Conclusions: Our findings expanded the aetiological genetic landscape of ID/GDD and showed evidence that both conditions are closely related at the molecular and functional levels.

About 30-70% of familial Alzheimer's disease (AD) cases are related to mutations in presenilin-1 gene (PSEN1). Although the role of mutations and common variants in AD had been extensively investigated, the contribution of rare or low frequency PSEN1 variants on AD risk remains unclear. In the current study, we performed a mutational screening of PSEN1 coding exons and flanking intronic sequences among 53 index cases with familial history of AD from Rio de Janeiro (Brazil). Two missense variants (rs63750592; rs17125721), one rare and a low frequency variant, and two intronic variants (rs3025786; rs165932) were identified. In silico tools were used to predict the functional impact of the variants, revealing no changes in protein functionality by exonic variants. Otherwise, all variants were predicted to alter splicing signals. Prediction results, together with previous reports, suggest a correlation between rs17125721 and AD. So, a subsequent case-control study to evaluate the role of rs1712572 on AD risk was performed in an additional sample of 120 AD sporadic cases and in 149 elderly healthy controls by TaqMan Genotyping Assay. Our data indicates a risk association for rs17125721 in familial AD cases (OR=6.0; IC95%=1.06-33.79; p=0.042). In addition, we tested the multiplicative interaction between allele ε4 of the apolipoprotein E (APOE) and rs17125721 and no statistical association was found. Taken together, our findings provide new insight about the genetic relevance of low frequency PSEN1 variants for familial AD development., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: Amongst Parkinson's disease (PD) genetic factors, mutations in LRRK2, SNCA, VPS35 and GBA genes are recognized causes of PD. Nonetheless, few genetic screenings have been conducted in families with a history of PD consistent with autosomal dominant inheritance (ADPD), and their relevance to the etiology of PD has been poorly explored in Latin American populations, such as the Brazilian one, with a high degree of admixture., Methods: In order to assess the contribution of specific mutations in LRRK2, SNCA, VPS35 and GBA genes to ADPD in Brazil, we conducted the first molecular evaluation in a cohort of 141 index cases from families with ADPD. Genomic DNA was isolated from peripheral blood or saliva, and the molecular analysis was performed by TaqMan allelic discrimination assays or bidirectional sequencing., Results: Heterozygous mutations in LRRK2 and GBA genes were identified in 10 (7.0%) probands, and all presented typical signs of classical PD. No mutations were found in SNCA or VPS35 genes., Conclusion: Our findings in a representative series of index cases from families with ADPD emphasize the important contribution of LRRK2 G2019S and GBA (L444P and N370S) mutations to parkinsonism in Brazilian families. The absence of mutations in VPS35 and SNCA genes reveals that they are uncommon causes of PD in Brazil, corroborating previous studies that also failed to detect these genetic variants in PD patients from other populations. Recent discoveries of novel causative genes of autosomal dominant forms of PD expand the investigative possibilities and should be targeted on future studies., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Ovarian xenografting is an auxiliary reproductive technique that allows the conservation of germplasm of high-value livestock and endangered species. The use of exogenous gonadotropins assists in developing xenografted tissues and obtaining viable follicles for in vitro embryo production; however, this use has not been reported in the xenografting of cats' (Felis catus) ovaries with C57BL/6 female SCID mice (Mus musculus) as recipients. Therefore, the aim of this study was to evaluate the responses of queens' ovaries to eCG when grafted into C57BL/6 female SCID mice. Ovarian cortex fragments from queens were grafted under the kidney capsule of 15 C57BL/6 SCID mice after bilateral ovariectomy. After 45 days, the recipients were divided into two groups: those that did not receive hormone induction (eCG-), which were euthanized at the time of induction, and those that received hormonal induction (eCG+), which were euthanized 48 hours later. All the tissues collected were histologically processed. The proportions of the different ovarian follicles were compared by chi-square test. The morphology of the follicles was compared between the experimental groups by Tukey (primordial, primary, and secondary follicles) and Kruskal-Wallis (antral follicles) tests. Macroscopically, we observed a few antral follicles that were over 1 mm in size in grafts treated with eCG. Microscopically, follicles of all categories were observed in the grafts, and all had normal morphology for the species studied. However, larger primordial and primary follicles were observed in the eCG+ transplants than those in the eCG- transplants. There was a decrease in primordial follicles and an increase in the other follicles, particularly in the antral follicles of the eCG+ group, a phenomenon that we propose to term "follicular right shift". Luteinized follicles were also observed in grafts treated with eCG. Therefore, treatment with eCG is effective for follicular development but does not provoke a good superovulatory response, so the correct application time should be identified. Other protocols should be tested, to obtain viable follicles that can be used for in vitro embryo production., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: Almost all patients with Fragile X Syndrome (FXS) exhibit a CGG repeat expansion (full mutation) in the Fragile Mental Retardation 1 gene (FMR1). Here, the authors report five unrelated males with FXS harboring a somatic full mutation/deletion mosaicism., Methods: Mutational profiles were only elucidated by using a combination of molecular approaches (CGG-based PCR, Sanger sequencing, MS-MLPA, Southern blot and mPCR)., Results: Four patients exhibited small deletions encompassing the CGG repeats tract and flanking regions, whereas the remaining had a larger deletion comprising at least exon 1 and part of intron 1 of FMR1 gene. The presence of a 2-3 base pairs microhomology in proximal and distal non-recurrent breakpoints without scars supports the involvement of microhomology mediated induced repair (MMBIR) mechanism in three small deletions., Conclusion: The authors data highlights the importance of using different research methods to elucidate atypical FXS mutational profiles, which are clinically undistinguishable and may have been underestimated.

Visceral leishmaniasis (VL) is one of the seven priority endemic diseases in the world. The clinical outcome of many infections is not only dependent on the pathogenic organism, but also on the genetic variability of the host susceptibility to infection. Mannose-binding lectin (MBL) is a protein that plays an important role in the innate immune system. The aim of this study was to compare the serum levels of MBL between healthy controls and carriers of VL. The VL cases were recruited randomly from the main hospitals and referral outpatient clinics for VL in São Luís, and from home visits. Determination of MBL protein levels was performed by enzyme-linked immunosorbent assay. Of the 161 patients with VL and the 161 healthy controls, 60.9 and 67.1% had high levels of MBL, respectively. There was no significant difference in MBL levels between cases and controls. Low socioeconomic status and living conditions are conducive to the occurrence of VL. Owing to the small number of existing studies, it is extremely important to conduct further studies on MBL levels and susceptibility to VL, especially in regions where the disease is endemic, such as Maranhão, Brazil.

The dysregulation of the endocannabinoid system is associated with cardiometabolic complications of obesity. Allelic variants in coding genes for this system components may contribute to differences in the susceptibility to obesity and related health hazards. These data have mostly been shown in Caucasian populations and in severely obese individuals. We investigated a multiethnic Brazilian population to study the relationships among the polymorphism 385C>A in an endocannabinoid degrading enzyme gene (FAAH), endocannabinoid levels and markers of cardiometabolic risk. Fasting plasma levels of endocannabinoids and congeners (anandamide, 2-arachidonoylglycerol, N-oleoylethanolamide and N-palmitoylethanolamide) were measured by liquid chromatography-mass spectrometry in 200 apparently healthy individuals of both genders with body mass indices from 22.5 ± 1.8 to 35.9 ± 5.5 kg/m2 (mean ± 1 SD) and ages between 18 and 60 years. All were evaluated for anthropometric parameters, blood pressure, metabolic variables, homeostatic model assessment of insulin resistance (HOMA-IR), adiponectin, leptin, C-reactive protein, and genotyping. The endocannabinoid levels increased as a function of obesity and insulin resistance. The homozygous genotype AA was associated with higher levels of anandamide and lower levels of adiponectin versus wild homozygous CC and heterozygotes combined. The levels of anandamide were independent and positively associated with the genotype AA position 385 of FAAH, C-reactive protein levels and body mass index. Our findings provide evidence for an endocannabinoid-related phenotype that may be identified by the combination of circulating anandamide levels with genotyping of the FAAH 385C>A; this phenotype is not exclusive to mono-ethnoracial populations nor to individuals with severe obesity.

The objective of this study was to perform a study of fragile X syndrome (FXS) in São Luís, Maranhão, in males residing in five specialized institutions. Two hundred thirty-eight males with intel-lectual disability of unknown etiology participated in this study. Blood samples were processed and stored until DNA extraction. Screening for FMR1 gene mutations was performed using non-isotopic polymerase chain reaction amplification and DNA sequencing using an ABI Prism 3130 automated sequencer. Two individuals (0.84%) were positive for FMR1 mutations. One had a mutation due to expansion of the CGG repeat beyond normal levels and the other had a deletion in exon 1 of the FMR1 gene, which was confirmed by sequencing. Both probands were over 18 years old, which demonstrates the late diagnosis of the condition in these individuals and reinforces the need to implement ef-fective programs for early diagnosis of FXS in the state of Maranhão. We found that FXS might be transmitted in the families of the two indi-viduals bearing the mutation, and that it is important to understand the mutation dynamics to provide better counseling to the family members of these two individuals.

Background: Amongst Parkinson's disease-causing genetic factors, missense mutations and genomic multiplications in the gene encoding α-synuclein are well established causes of the disease, although genetic data in populations with a high degree of admixture, such as the Brazilian one, are still scarce., Methods: In this study, we conducted a molecular screening of α-synuclein point mutations and copy number variation in the largest cohort of Brazilian patients with Parkinson's disease (n = 549) and also in twelve Portuguese and one Bolivian immigrants. Genomic DNA was isolated from peripheral blood leukocytes or saliva, and the mutational screening was performed by quantitative and qualitative real-time PCR., Results: The only alteration identified was the p.E46K mutation in a 60-year-old man, born in Bolivia, with a familial history of autosomal dominant Parkinson's disease. This is the second family ever reported, in which this rare pathogenic mutation is segregating. The same mutation was firstly described ten years ago in a Spanish family with a neurodegenerative syndrome combining parkinsonism, dementia and visual hallucinations. The clinical condition of our proband reveals a less aggressive phenotype than previously described and reinforces that marked phenotypic heterogeneity is common among patients with Parkinson's disease, even among those carriers sharing the same mutation., Conclusion: Our findings add new insight into the preexisting information about α-synuclein p.E46K, improving our understanding about the endophenotypes associated to this mutation and corroborate that missense alterations and multiplications in α-synuclein are uncommon among Brazilian patients with Parkinson's disease., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Recently, we defined a minimal overlapping region for causal Xp11.22 copy number gains in males with intellectual disability (ID), and identified HECT, UBA and WWE domain-containing protein-1 (HUWE1) as the primary dosage-sensitive gene, whose overexpression leads to ID. In the present study, we used this minimal interval to search for HUWE1 copy number variations by quantitative polymerase chain reaction in a large cohort of Brazilian males with idiopathic ID. We detected two unrelated sporadic individuals with syndromic ID carrying unique overlapping duplications encompassing HUWE1. Breakpoint junction analysis showed a simple tandem duplication in the first patient, which has probably arisen by microhomology-mediated break-induced repair mechanism. In the second patient, the rearrangement is complex having an insertion of an intrachromosomal sequence at its junction. This kind of rearrangement has not been reported in Xp11.22 duplications and might have emerged by a replication- or recombination-based mechanism. Furthermore, the presence of infantile seizures in the second family suggests a potential role of increased KDM5C expression on epilepsy. Our findings highlight the importance of microduplications at Xp11.22 to ID, even in sporadic cases, and reveal new clinical and molecular insight into HUWE1 copy number gains.

Neoproterozoic carbonate rocks comprise different stratigraphic units in the southern part of the Espinhaço Ridge, Minas Gerais, Brazil. C, O- and Sr-isotope analyses were carried out along four selected stratigraphic sections across these formations. These are: (i) the Rio Pardo Grande Formation in the upper portion of the Espinhaço Supergroup, sampled in section 3; (ii) Macaúbas Group laminated limestones (Tijucuçu Farm) and dolostone layers (Domingas Formation) have been respectively sampled along the so-called sections 1 and 2, and (iii) the lower stratigraphic units of the Bambuí Group, sampled in section 4. Laminated limestone samples from the Macaúbas Group have δ13C values as high as 10.9‰ decreasing up section to -1.1‰ and 87Sr/86Sr values vary from 0.7072 to 0.7076, a range commonly observed in Cryogenian rocks. In section 2, dolomitic samples exhibit 87Sr/86Sr from 0.7076 to 0.7077 while in section 3, 87Sr/86Sr from 0.7074 to 0.7079. In section 4, 87Sr/86Sr values are around 0.7080. The values of 87Sr/86Sr observed in carbonate samples from the Macaúbas Group are similar to those observed in the Sr-isotope secular curve for the Neoproterozoic. Carbonate samples from the base of the Bambuí Group correlate with Ediacaran fingerprints, after the Marinoan (ca. 635 Ma) glaciation.

Oligophrenin-1 (OPHN1) is one of at least seven genes located on chromosome X that take part in Rho GTPase-dependent signaling pathways involved in X-linked intellectual disability (XLID). Mutations in OPHN1 were primarily described as an exclusive cause of non-syndromic XLID, but the re-evaluation of the affected individuals using brain imaging displayed fronto-temporal atrophy and cerebellar hypoplasia as neuroanatomical marks. In this study, we describe clinical, genetic and neuroimaging data of a three generation Brazilian XLID family co-segregating a novel intragenic deletion in OPHN1. This deletion results in an in-frame loss of exon 7 at transcription level (c.781&#95;891del; r.487&#95;597del), which is predicted to abolish 37 amino acids from the highly conserved N-terminal BAR domain of OPHN1. cDNA expression analysis demonstrated that the mutant OPHN1 transcript is stable and no abnormal splicing was observed. Features shared by the affected males of this family include neonatal hypotonia, strabismus, prominent root of the nose, deep set eyes, hyperactivity and instability/intolerance to frustration. Cranial MRI scans showed large lateral ventricles, vermis hypoplasia and cystic dilatation of the cisterna magna in all affected males. Interestingly, hippocampal alterations that have not been reported in patients with loss-of-function OPHN1 mutations were found in three affected individuals, suggesting an important function for the BAR domain in the hippocampus. This is the first description of an in-frame deletion within the BAR domain of OPHN1 and could provide new insights into the role of this domain in relation to brain and cognitive development or function.

An increasing number of neurodevelopmental diseases have been associated with disruption of chromatin remodeling in eukaryotes. Lysine(K)-specific demethylase 5C (KDM5C) is a versatile epigenetic regulator that removes di- and tri-methyl groups of lysine 4 on histone H3 (H3K4) from transcriptional targets and is essential for neuronal survival and dendritic growth. Mutations in KDM5C gene, located at Xp11.22, have been reported as an important cause of both syndromic and non-syndromic X-linked intellectual disability (XLID) in males. The aim of this study was to evaluate the prevalence and spectrum of KDM5C mutations among Brazilian patients with XLID. To access the impact of KDM5C variants on XLID, a cohort of 143 males with a family history of intellectual disability (ID) suggestive of X-linked inheritance were enrolled. Common genetic causes of XLID were previously excluded and the entire coding and flanking intronic sequences of KDM5C gene were screened by direct Sanger sequencing. Seven nucleotide changes were observed: one pathogenic mutation (c.2172C>A, p.Cys724*), one novel variant with unknown value (c.633G>C, p.Arg211Arg) and five apparently benign sequence changes. In silico analysis of the variants revealed a putative creation of an Exonic Splicing Enhancer sequence by the silent c.633G>C mutation, which co-segregates with the ID phenotype. Our results point out to a KDM5C pathogenic mutational frequency of 0.7% among males with probable XLID. This is the first KDM5C screening among ID males from a country in Latin America and provides new clues about the significance of KDM5C mutations for genetic counseling., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Parkinson's disease is the second most frequent neurodegenerative disorder in the world, affecting 1-2% of individuals over the age of 65. The etiology of Parkinson's disease is complex, with the involvement of gene-environment interactions. Although it is considered a disease of late manifestation, early-onset forms of parkinsonism contribute to 5-10% of all cases. In the present study, we screened mutations in coding regions of PARK2 and PINK1 genes in 136 unrelated Brazilian patients with early-onset Parkinson's disease through automatic sequencing. We identified six missense variants in PARK2 gene: one known pathogenic mutation, two variants of uncertain role, and three nonpathogenic changes. No pathogenic mutation was identified in PINK1 gene, only benign polymorphisms. All putative pathogenic variants found in this study were in heterozygous state. Our data show that PARK2 point mutations are more common in Brazilian early-onset Parkinson's disease patients (2.9%) than PINK1 missense variants (0%), corroborating other studies worldwide.

We previously reported on nonrecurrent overlapping duplications at Xp11.22 in individuals with nonsyndromic intellectual disability (ID) harboring HSD17B10, HUWE1, and the microRNAs miR-98 and let-7f-2 in the smallest region of overlap. Here, we describe six additional individuals with nonsyndromic ID and overlapping microduplications that segregate in the families. High-resolution mapping of the 12 copy-number gains reduced the minimal duplicated region to the HUWE1 locus only. Consequently, increased mRNA levels were detected for HUWE1, but not HSD17B10. Marker and SNP analysis, together with identification of two de novo events, suggested a paternally derived intrachromosomal duplication event. In four independent families, we report on a polymorphic 70 kb recurrent copy-number gain, which harbors part of HUWE1 (exon 28 to 3' untranslated region), including miR-98 and let-7f-2. Our findings thus demonstrate that HUWE1 is the only remaining dosage-sensitive gene associated with the ID phenotype. Junction and in silico analysis of breakpoint regions demonstrated simple microhomology-mediated rearrangements suggestive of replication-based duplication events. Intriguingly, in a single family, the duplication was generated through nonallelic homologous recombination (NAHR) with the use of HUWE1-flanking imperfect low-copy repeats, which drive this infrequent NAHR event. The recurrent partial HUWE1 copy-number gain was also generated through NAHR, but here, the homologous sequences used were identified as TcMAR-Tigger DNA elements, a template that has not yet been reported for NAHR. In summary, we showed that an increased dosage of HUWE1 causes nonsyndromic ID and demonstrated that the Xp11.22 region is prone to recombination- and replication-based rearrangements., (Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Parkinson's disease is one of the most common neurodegenerative disorders associated with aging, reaching ∼ 2% of individuals over 65 years. Knowledge achieved in the last decade about the genetic basis of Parkinson's disease clearly shows that genetic factors play an important role in the etiology of this disorder. Exon dosage variations account for a high proportion of Parkinson's disease mutations, mainly for PARKIN gene. In the present study, we screened genomic rearrangements in SNCA, PARKIN, PINK1 and DJ-1 genes in 102 Brazilian Parkinson's disease patients with early onset (age of onset ⩽ 50 years), using the multiplex ligation-dependent probe amplification method. Family history was reported by 24 patients, while 78 were sporadic cases. Screening of exon dosage revealed PARKIN and PINK1 copy number variations, but no dosage alteration was found in SNCA and DJ-1 genes. Most of the carriers harbor heterozygous deletions or duplications in the PARKIN gene and only one patient was found to have a deletion in PINK1 exon 1. Data about dosage changes are scarce in the Brazilian population, which stresses the importance of including exon dosage analysis in Parkinson's disease genetic studies.

Point mutations and genomic rearrangements in the MECP2 gene are the major cause of Rett syndrome (RTT), a pervasive developmental disorder affecting almost exclusively females. MECP2 mutations were also identified in patients with autism without RTT. In this study, we present a mutational and gene dosage analysis of the MECP2 in a cohort of 60 Brazilian males with autistic features but not RTT. No duplication or deletion was identified. Sequencing analysis, however, revealed four MECP2 sequence variations. Three of them were previously discussed as non disease causing mutations and one mutation (p.T160S) was novel. It affects a highly conserved amino acid located within the MBD domain, a region of the protein involved in specific recognition and interaction with methylated CpG dinucleotides. The p.T160S variation was not found in the control sample. This mutation may represent a potential genetic factor for autistic phenotype and should be object of further studies., (Copyright © 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Mutations in the Jumonji AT-rich interactive domain 1C (JARID1C/SMCX/KDM5C) gene, located at Xp11.22, are emerging as frequent causes of X-linked intellectual disability (XLID). KDM5C encodes for a member of an ARID protein family that harbors conserved DNA-binding motifs and acts as a histone H3 lysine 4 demethylase, suggesting a potential role in epigenetic regulation during development, cell growth and differentiation. In this study, we describe clinical and genetic findings of a Brazilian family co-segregating a novel nonsense mutation (c.2172C>A) in exon 15 of KDM5C gene with the intellectual disability phenotype. The transition resulted in replacement of the normal cysteine by a premature termination codon at position 724 of the protein (p.Cys724X), leading to reduced levels of KDM5C transcript probably due to nonsense mediated mRNA decay. The clinical phenotype of the proband, who has two affected brothers and a mild cognitively impaired mother, consisted of short stature, speech delay, hyperactivity, violent behavior and high palate, besides severe mental retardation. Our findings extend the number of KDM5C mutations implicated in XLID and highlight its promise for understanding neural function and unexplained cases of XLID., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Background and Purpose: Mutations in the leucine-rich repeat kinase 2 gene (LRRK2) have been associated with Parkinson's disease (PD), and the majority of the pathogenic variants are located in the ROC and MAPKKK domains., Methods: Exons 29-31 and 38-44 (ROC and MAPKKK domains) were sequenced in 204 patients with PD, mostly Brazilian., Results: We identified four polymorphisms, a novel silent variant p.R1398R and four substitutions: p.T1410M, p.G2019S, p.Y2189C and the novel variant p.C2139S., Conclusions: The most prevalent mutation was the p.G2019S (2.4%). We consider that the p.T1410M and the p.Y2189C variants are probably polymorphisms and that the p.C2139S mutation is potentially pathogenic., (© 2010 The Author(s). European Journal of Neurology © 2010 EFNS.)

In the last decade, several genes have been linked to Parkinson's disease (PD), including GIGYF2, ATP13A2 and GBA. To explore whether mutations in these genes contribute to development of PD in the Brazilian population, we screened 110 patients with early-onset PD. No clearly pathogenic mutations were identified in ATP13A2 and GIGYF2. In contrast, we identified a significantly higher frequency of known pathogenic mutations in GBA gene among the PD cases (6/110=5.4%) when compared to the control group (0/155) (P=0.0047). Our results strongly support an association between GBA gene mutations and an increased risk of PD. Mutations in GIGYF2 and ATP13A2 do not seem to represent a risk factor to the development of PD in the Brazilian population. Considering the scarcity of studies on GIGYF2, ATP13A2 and GBA mutation frequency in Latin American countries, we present significant data about the contribution of these genes to PD susceptibility., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

MicroRNAS (miRNAs) are a class of endogenously single-stranded non-coding RNA molecules that can negatively modulate the expression of target messenger RNAs by 3' UTR base pairing. During the processing of a miRNA, a network of orchestrated molecular events provides a dynamic manner to posttranscriptionally modulate gene expression. Recent research has demonstrated that although these molecules are small, they are involved in several crucial biological functions, as well as, in a broad spectrum of human diseases. In this review, we highlighted the current knowledge on the miRNA pathway field, focusing on how the disruption of the miRNA-mediated silencing pathways could lead to the pathogenesis of neurological disorders. The potential use of miRNAs as diagnostic/prognostic markers and the possibility of reversing the effects of some miRNA polymorphisms/mutations by promising therapeutics procedures have brought new perspectives into the treatment of human pathologies.

We studied the methylation status of the p15(INK4B) and p16(INK4A) genes in 47 pediatric patients with primary MDS, its correlation with subtype, and the role of p15(INK4B) and p16(INK4A) in the evolution of MDS toward AML. Aberrant methylation of the p15(INK4B) gene was detected in 15 of 47 patients (32%), whereas only four patients demonstrated methylation of the p16(INK4A) gene (8%). The frequency of p15(INK4B) methylation was significantly higher in RAEB and RAEB-t subtypes (p<0.003). Aberrant methylation of the p16(INK4A) gene was also more frequent in the subtypes that characterize advanced stages of the disease (p<0.05). Evolution of disease was verified in 17 (36%) of the 47 patients. The association of p15(INK4B) and p16(INK4A) methylation status with evolution of disease was clearly significant (p<0.008 and p<0.05, respectively). These results suggest that methylation of the p15(INK4B) and p16(INK4A) genes is an epigenetic biomarker of pediatric disease evolution.

Structural variations that affect the copy number of the MECP2 gene were shown to cause mental retardation in males by driving the overexpression of this gene. To access the impact of these rearrangements in males with unexplained mental retardation, we have performed a quantitative real-time polymerase chain reaction assay using SYBR Green I chemistry to quantify MECP2 gene copy number in 145 Brazilian males with mental retardation of unknown cause. Three patients carrying MECP2 duplications (approximately 2%) were identified. The analysis of additional markers flanking the MECP2 region showed that the duplications observed are nonrecurrent. Expression studies in two of these patients revealed the overexpression of the MECP2 gene compared to the expression level observed in controls. These findings corroborate other recent reports in the literature and highlight that the overexpression of MECP2 caused by duplications involving this gene is a relatively frequent genetic cause of mental retardation in males, highlighting the importance of MECP2 gene dosage for diagnostic purposes in such cases.

We determined whether ADRbeta3 polymorphism is associated with obesity-related traits in 140 obese patients. Molecular analysis was performed by PCR and RFLP. Individuals carrying the Arg64 allele had a lower waist-to-hip ratio, higher adiponectin and high-density lipoprotein cholesterol levels, and a tendency towards lower blood pressure. In contrast, Trp64/Trp64 carriers were at greater risk for dysmetabolic phenotypes (odds ratio = 2.88, P = 0.03).

Background: This study assessed in obese Brazilians subjects whether a common variant of leptin gene, -2548G>A, is associated with blood pressure changes., Methods: A total of 140 subjects, 99 women; mean age of 45.2 +/- 12.4 years; body mass index (BMI) = 38.5 +/- 8.0 kg/m2 were included. Blood pressure was recorded using Dinamap 1846 (Critikon, Tampa, FL). Molecular analysis was made by use of PCR and restriction fragment-length polymorphism analysis. Plasma insulin and leptin concentrations were determined by radioimmunoassay., Results: AA homozygotes, in comparison with the G-allele carriers, showed significant lower levels of systolic, diastolic, and mean arterial pressure (120 +/- 10 vs. 132 +/- 17 mm Hg, P = 0.01; 75 +/- 6 vs. 84 +/- 12 mm Hg, P = 0.009; 92 +/- 7 vs. 100 +/- 12 mm Hg, P = 0.007, respectively). The differences in blood pressure remained significant after adjusting for the influence of gender, age, obesity, and body fat distribution as well as for leptin, insulin, and homeostasis model assessment of insulin resistance. A stepwise regression analysis confirmed that the LEP AA genotype independently predicted blood pressure changes. On the other hand, in GG homozygotes, insulinemia showed a significant association with blood pressure values. This suggests that common LEP genotype carriers exhibiting high insulin levels, reflecting an insulin-resistant state, were particularly prone to higher blood pressure levels., Conclusions: Our results showing that higher blood pressure levels were found with the most prevalent -2548G>A genotype, whereas patients with the AA genotype seemed to be protected from hypertension, indicate that the -2548G>A polymorphism of LEP appears to be an important mediator of obesity hypertension.

MeCP2 is a protein that functions as a key factor in epigenetic transcriptional regulation. Mutations in MECP2 gene have been reported as being the major cause of Rett syndrome. These mutations may also cause a wide spectrum of neurological disorders in males. Here, we report the identification of the mutation p.P405L in a 19-year-old Brazilian male with mental retardation. This variant is localized in a highly conserved aminoacid from the carboxy terminal domain and may affect the protein function. Segregation analysis on the patient's mother revealed that this is a de novo mutation and it was not identified in the control sample. The programs SIFT, PolyPhen and A-GVGD considered that the p.P405L may be damaging. Despite the high frequency of non pathogenic variants that have been identified in this gene, our data lead us to consider the p.P405L a disease-causing mutation.

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have emerged as a potential common cause for both sporadic and familial Parkinson's Disease (PD) in different populations. The pleomorphic features exhibited by LRRK2 mutation carriers and the central role of Lrrk2 protein in the proper functioning of central nervous system suggest that mutations in this protein might be involved in multiple cellular processes leading to other neurodegenerative disorders than PD. The location of LRRK2 gene on chromosome 12, close to a linkage peak for familial late-onset Alzheimer's Disease (AD), highlights that LRRK2 mutations might be involved in AD pathogenesis. We screened the most common LRRK2 mutation (p.G2019S) in a series of 180 consecutive patients clinically diagnosed with Alzheimer Disease (AD). We identified the p.G2019S in one AD patient with no PD signs, indicating that this mutation is not a common etiological factor for AD in our population (0.5%), corroborating recent data found in Norwegian, North American, Chinese and Italian populations. Nevertheless, these observations together with new information about the Lrrk2 critical multifunctionality do not rule out the possible influence of other variants within LRRK2 in AD, so that other screenings focusing in the whole extension of the LRRK2 using larger sized confirmed AD sample are urgently needed.

Recent evidence shows that almost 92% of the DS children are born from young mothers, suggesting that other risk factors than advanced maternal age must be involved. In this context, some studies demonstrated a possible link between DS and maternal polymorphisms in genes involved in folate metabolism. These polymorphisms, as well as low intake of folate could generate genomic instability, DNA hypomethylation and abnormal segregation, leading to trisomy 21. We compared the frequency of CBS 844ins68, MTR 2756A>G, RFC-1 80G&gt A and TC 776C>G polymorphisms among 114 case mothers and 110 matched controls, in order to observe whether these variants act as risk factors for DS. The genotype distributions revealed that there were not significant differences between both samples. However, when we proceed the multiplicative interaction analyses between the four polymorphisms described above together with the previously studied MTHFR 677C>T, MTHFR 1298A>C and MTRR 66A>G polymorphisms, our results show that the combined genotype TC 776CC / MTHFR 677TT and TC 776CC / MTR 2756AG were significantly higher in the control sample. Nevertheless, there was no significant association after Bonferroni correction. Our results suggest that maternal folate-related polymorphisms studied here have no influence on trisomy 21 susceptibility in subjects of Brazilian population.

Mutations in the Leucine-rich repeat kinase 2 (LRRK2) gene are known as a common cause of Parkinson's disease (PD) among patients from different geographic origins. In this study, we evaluated the prevalence of LRRK2 mutations in exons 31 and 41 in a cohort of 154 consecutive, unrelated Brazilian patients with familial or sporadic PD, including early and late onset patients. The LRRK2 p.G2019S mutation was present in heterozygous state in three index cases (approximately 2%), and in three additional relatives. No carriers of this mutation were found among 250 control chromosomes. Clinically, all mutation-positive patients presented a typical PD phenotype and a good response to levodopa. Mutation segregation analysis in a large sibling showed incomplete penetrance of the p.G2019S. Our findings suggest that the LRRK2 p.G2019S mutation has a substantial contribution to PD susceptibility among Brazilian population and add new clues to current research of this disease.

Polymorphisms in genes encoding folate metabolizing enzymes have been linked to an increased risk of maternal chromosomal nondisjunction in several populations. With the purpose of evaluating this relationship, we compared the frequencies of 677C>T and 1298A>C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) and 66A>G in the methionine synthase reductase gene (MTRR) between 103 young mothers of Down syndrome (DS) individuals and 108 control mothers, whose offspring was karyotypically normal, correlating it with an estimative of folate and - related micronutrients levels intake. Maternal and paternal transmission frequencies of MTHFR 677T allele were also examined to access potential parent-of-origin effects. PCR-RFLP for genomic DNA was accomplished and allele/genotype frequencies differences were determined using the x(2) test, whereas pattern of transmission of the MTHFR 677 allele was analyzed by transmission disequilibrium test. None of the polymorphisms seemed to be more frequent in case mothers than in controls, either individually or combined. The estimative of nutritional intake revealed that folate consumption median was inadequate in both groups, whereas methionine and zinc consumption medians were significantly greater in control mothers. It suggests that such interaction between genetic profile and environment could predispose this sub group of women to have a DS child. Additional studies focusing the interaction between nutritional intakes, biochemical data and folate pathway polymorphisms are needed to confirm the present results. The possibility of neutralize the biochemical negative effects of folate-related polymorphisms through oral supplementation could provide new targets for DS prevention.

Obesity is due to the combined effects of genes, environment, lifestyle, and the interactions of these factors. The adrenergic receptor beta3 (beta3-AR), leptin (LEP) and leptin receptor (LEPR) genes have been intensively evaluated in the search of variants that could be related to obesity and its cardiometabolic complications. The results of most of these studies have been controversial. In the present study, we investigated the relationship of the beta3-AR p.W64R, LEP c.-2548G>A and LEPR p.Q223R gene variants with body mass index (BMI), in Brazilian subjects of different genetic backgrounds and ethnic origins. Two hundred obese patients (60 males, 140 females, BMI > or = 30 kg/m2) were screened and compared to 150 lean healthy subjects (63 males, 87 females, BMI < or = 24 kg/m2). Genomic DNA was extracted and amplified by polymerase chain reaction. Polymerase chain reaction products were digested with specific restriction enzymes and separated by electrophoresis. There was no significant difference in the genotype frequency of the beta3-AR p.W64R and the LEP c.-2548G>A polymorphisms, between lean and obese subjects. However, the genotype and allele frequencies of the LEPR p.Q223R variant were significantly different between the normal weight and obese groups. Haplotype analysis has shown an association between the G/G allelic combination of c.-2548G>A LEP and c.668A>G LEPR, in obese subjects. Our results suggest that genetic variability in the leptin receptor is associated with body weight regulation, the LEPR p.Q223R variant being related to BMI increase. The haplotype combination of LEP c.-2548G>A and LEPR p.Q223R variants was related to a 58% increase in obesity risk.

MeCP2 is a protein that selectively binds to methylated cytosines through its methyl-CpG-binding domain (MBD) and connects DNA methylation to transcriptional repression. Mutations in MECP2 gene, located in Xq28, have been reported as being the major cause of Rett syndrome and are also associated with some cases of X-linked mental retardation in both males and females. In this study, we present the first screening in the MECP2 gene in a Brazilian cohort of 239 unrelated males with idiopathic mental retardation. Eight sequence variations were observed in 10 patients: one novel putative pathogenic variant, two never described variants of unknown pathogenic value and five non-pathogenic variations. We conclude that in mentally retarded Brazilian males, non-pathogenic variants in the MECP2 gene are more common than actual pathogenic mutations, and therefore alterations in this gene have a weak relationship with mental retardation in males.

Significant evidences have brought new insights on the mechanisms by which epigenetic machinery proteins regulate gene expression, leading to a redefinition of chromatin regulation in terms of modification of core histones, DNA methylation, RNA-mediated silencing pathways, action of methylation-dependent sensitive insulators and Polycomb/Trithorax group proteins. Consistent with these fundamental aspects, an increasing number of human pathologies have been found to be associated with aberrant epigenetics regulation, including cancer, mental retardation, neurodegenerative symptoms, imprinting disorders, syndromes involving chromosomal instabilities and a great number of human life-threatening diseases. The possibility of reversing epigenetic marks, in contrast to genetic code, may provide new pharmacological targets for emerging therapeutic intervention.

Several genes play a major role in obese phenotypes, and studies suggest that genetic variations among individuals, as well as their lifestyles, may bring about different body compositions. Among these genes, LEP, which codifies leptin, and the LEPR gene encoding its receptor were extensively studied for variants that could explain the obese phenotype. The LEPR p.Q223R gene polymorphism was analyzed in a sample of obese and nonobese individuals from Brazil to evaluate the role of this polymorphism in the obese phenotype in the population. Two hundred obese patients (60 males, 140 females, body mass index (BMI) >30 kg/m2) were screened, together with 150 lean or normal healthy individuals (63 males, 87 females, BMI <24 kg/m2). Genomic DNA was extracted and amplified by polymerase chain reaction (PCR). PCR products were digested with the restriction of endonuclease MspI, and separated by electrophoresis through an 8% polyacrilamide gel stained with silver nitrate. There was a significant difference in LEPR p.Q223R polymorphism frequency when comparing obese and lean subjects, with an odds ratio of 1.92 and a 95% confidence interval of 1.15-3.22 (P = 0.013). There is a strong association of the LEPR p.Q223R gene polymorphism with obesity in Brazil.

The recently identified gene ARX (Aristalles-Related Homeobox) codifies the ARX protein, an important transcript factor that belongs to one of the three largest classes of homeoproteins, the paired (Prd) class. Several mutations have been identified in ARX gene, which is responsible for a wide spectrum of phenotypes, including syndromic as well as non syndromic forms of mental retardation. One of the mutations, the c.428-451 dup (24 bp) is the most frequent identified in the ARX gene. This duplication leads to an expansion of the second polyalanine tract of ARX protein. We have reported the identification of a Brazilian family segregating the c.428-451 dup (24 bp) in ARX gene.

FRAXE fragile site associated mental retardation (FRAXE MR) belongs to a group of non-syndromic X-linked mental retardation. Two genes, FMR2 and FMR3 (likely a non-coding RNA) are transcribed from the FRAXE CpG island in the opposite directions. While the contribution of the FMR2 gene to FRAXE MR has been demonstrated, the role of the FMR3 gene is not known. We have screened 441 Brazilian mentally handicapped males for CCG repeat expansions in the FMR2 gene and identified a boy with a mutation (c.-414&#95;-357del58) immediately distal to the FRAXE CCG repeat. We have established a skin fibroblast cell line from this patient and tested expression of both FMR2 and FMR3 genes. Reverse transcriptase PCR studies on the FMR2 and FMR3 genes showed that only the FMR3 gene transcription was abolished, suggesting a possible causal relationship between the lack of FMR3 expression and mental retardation in this patient. In the literature, there have been few deletions described near the FRAXE CCG repeat, but none was followed with expression studies. This is the first study showing missing expression in the FMR3 gene with normal FMR2 transcription leading to FRAXE mutation-likely phenotype. The FMR3 gene is likely a non-coding RNA gene. So far all individuals with FRAXE CCG repeat expansions and cytogenetically detectable FRAXE fragile site have both FMR2 and FMR3 gene expression abolished. Although the function of the FMR3 gene is not known, our present study together with previous studies on FRAXE MR suggest that it may play role in the processes underpinning normal learning and memory.

Pb concentration and Pb isotopic composition are known to represent powerful tools to investigate the history of Pb pollution in water and sediments. In this paper, we present and discuss the results of a detailed study of sediments deposited in the Paranoá Lake, a 44-year-old artificial reservoir in Brasília, central Brazil. Pb concentration and isotopic composition of the sediments were obtained by ID-TIMS, on three different sample fractions: leachate, residue, and bulk sample. The leachate phase has proven to be most efficient to distinguish between anthropogenic and natural Pb inputs. In the Paranoá lake, important sources of contamination were recognized, producing higher Pb concentrations (max. 37.68 ppm) and significant variations in Pb isotopic composition, relative to the regional geogenic background. Contamination of the sediments due to anthropogenic activity produced less radiogenic Pb isotopic compositions (206Pb/207Pb=1.15-1.17), compared with the regional natural composition (206Pb/207Pb=1.19-1.25). 210Pb analyses along one bore hole which sampled the entire sediment section indicated a sedimentation rate of 8.2+/-1.8 mm/year. The combined use of the 210Pb ages and Pb isotopic compositions of these samples revealed three distinct periods in the lake history: (1) the period of the time formation of the lake in 1959 until ca. 1970 was characterized by the deposition of sediments displaying more radiogenic Pb isotopic signature, (2) the time interval from the start of the process of eutrophication at 1970, until 1995, was characterized by the deposition of sediments having less radiogenic average compositions, and (3) from 1995 until the present represents a period of recovery of water quality, after two sewage treatment stations started to operate.

In mammals, methyl-CpG binding proteins play a significant role in the control of gene expression through their association with chromatin-remodeling complexes. Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome and have also been reported in a number of X-linked mental retardation diseases. In this study, DNA samples from 363 male individuals with syndromic and non-syndromic mental retardation and other psychiatric diseases were screened for A140V (419C>T) mutation in the MECP2 gene, considered the most frequent MECP2 mutation in males. No 419C>T was found suggesting that the A140V mutation in the MECP2 gene is not a common cause of mental retardation in males. Recently, a new and abundant isoform of MECP2 was described, which has an alternative N-terminus, translated from exon 1, that was previously thought to be non-coding and has been excluded from many mutational screening, as well, the 5' and 3' UTR regions. We consider essential proceeding further screening in the whole extension of the MECP2 gene using clinically well-documented and larger sized sample to assure the overall contribution of MECP2 to mental retardation.

Spinocerebellar ataxia type 3 is the most common form of autosomal dominant cerebellar ataxia. It is a severe progressive neurological disorder caused by an expansion of an exonic CAG repeat of the MJD1 gene. The repeated sequence is polymorphic among both normal individuals and patients. In general, expanded alleles are paternally inherited and the disorder exhibits anticipation. We performed a PCR-based study to determine polymorphisms of the number of CAG repeats of the MJD1 gene in an anonymous sample of normal Brazilian individuals. We also analyzed DNA samples from 9 patients with ataxia. We identified 29 different allele sizes ranging from 12 to 40 CAG repeats, with heterozygosity of 79%. The distribution of allele sizes showed two major peaks of 16 (7%) and 26 (10.1%) CAG repeats. When grouping normal alleles by size, we observed that the distribution varies between males and females, and a significant deviation from the Hardy-Weinberg equilibrium was observed with an excess of normal large alleles among males. We also detected expanded alleles with 68-73 CAG repeats in 3 out of 9 ataxic patients.