Next-Generation Sequencing for Molecular Diagnosis of Cystic Fibrosis in a Brazilian Cohort.

Cystic fibrosis (CF), an autosomal recessive genetic disease, is recognized as one of the most prevalent diseases in Caucasian populations. Epidemiological data show that the incidence of CF varies between countries and ethnic groups in the same region. CF occurs due to pathogenic variants in the gene encoding cystic fibrosis transmembrane conductance regulator (CFTR), located on chromosome 7q31.2. To date, more than 2,000 variants have been registered in the CFTR database. The study of these variants leads to the diagnosis and the possibility of a specific treatment for each patient through precision medicine. In this study, complete screening of CFTR was performed through next-generation sequencing (NGS) to gain insight into the variants circulating in the population of Rio de Janeiro and to provide patient access to treatment through genotype-specific therapies. Samples from 93 patients with an inconclusive molecular diagnosis were subjected to full-length screening of CFTR using an Illumina NGS HiSeq platform. Among these patients, 46 had two pathogenic variants, whereas 12 had only one CFTR variant. Twenty-four variants were not part of our routine screening. Of these 24 variants, V938Gfs∗37 had not been described in the CF databases previously. This research achieved a molecular diagnosis of the patients with CF and identification of possible molecular candidates for genotype-specific treatments.

Generation of patient-specific pluripotent induced stem cell line UFRJi007-A from a Brazilian familial amyotrophic lateral sclerosis patient.

Induced pluripotent stem cell (iPSC) line were generated from erythroblasts of a Brazilian patient with familiar form of amyotrophic lateral sclerosis (ALS). NGS analysis demonstrated that patient carried a mutation in SOD1 gene, as well as a deletion in FUS gene. CytoTune™-iPS 2.0 Sendai Reprogramming Kit (containing the reprogramming factors OCT3/4, KLF4, SOX2 and cMYC) was used to generate the cell lines. The iPSCs express pluripotency markers, have normal karyotype and differentiated spontaneously in the three germ layers. The expression of Sendai virus was lost in all iPSC lines after 15 passages.

Identification of the MC4R start lost mutation in a morbidly obese Brazilian patient.

BACKGROUND: Melanocortin 4 receptor gene (MC4R) is an important regulator of food intake, body weight, and blood pressure. Mutations in MC4R are associated with the most common form of nonsyndromic monogenic obesity. MC4R variations have an autosomal co-/dominant model of inheritance. MC4R screening could reveal individuals previously unrecognized with Mendelian form of obesity for further clinical management and genetic counseling. However, there are limited data regarding MC4R variants in patients with obesity from Brazil. The aim of this study was to screen the coding region of the MC4R gene in a Brazilian cohort of severely obese adults and to investigate the phenotype-genotype correlation within MC4R variant carriers. METHODS: This study comprised 157 adult participants, stratified according to the period of obesity onset. The first group included 97 patients with childhood-onset obesity (0-11 years) and the second group comprised 60 subjects with adolescence/youth-onset obesity (12-21 years). The entire coding region of MC4R gene was screened by Sanger sequencing. RESULTS: As a result, five previously described variants (Met1?, Ser36Thr, Val103Ile, Ile98=, and Phe202Leu) were identified. Met1? is a start lost codon variant, which affects the translation of MC4R. It was found in a female patient with childhood-onset obesity. We also compared the anthropometric and metabolic parameters between patients with MC4R missense variants (Ser36Thr, Val103Ile, and Phe202Leu) and noncarriers. Patients carrying MC4R variants had higher median of waist-hip ratio when compared to noncarriers (P=0.048). These missense variants were also associated with hypertension (P=0.014). Additionally, Val103Ile carriers had lower diastolic blood pressure and lower systolic blood pressure compared to noncarriers (P=0.020 and P=0.065, respectively). Val103Ile was also associated with hypertension (P=0.003). CONCLUSION: This study showed the prevalence of MC4R variants in a cohort of Brazilian adults with severe obesity. We also identified significant phenotype differences between carriers and noncarriers of missense variants in our sample, suggesting an important role of MC4R on body fat distribution and blood pressure.

Exon dosage variations in Brazilian patients with Parkinson's disease: analysis of SNCA, PARKIN, PINK1 and DJ-1 genes.

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.