Characterization of Mutations Causing CYP21A2 Deficiency in Brazilian and Portuguese Populations.

Deficiency of 21-hydroxylase enzyme (CYP21A2) represents 90% of cases in congenital adrenal hyperplasia (CAH), an autosomal recessive disease caused by defects in cortisol biosynthesis. Computational prediction and functional studies are often the only way to classify variants to understand the links to disease-causing effects. Here we investigated the pathogenicity of uncharacterized variants in the CYP21A2 gene reported in Brazilian and Portuguese populations. Physicochemical alterations, residue conservation, and effect on protein structure were accessed by computational analysis. The enzymatic performance was obtained by functional assay with the wild-type and mutant CYP21A2 proteins expressed in HEK293 cells. Computational analysis showed that p.W202R, p.E352V, and p.R484L have severely impaired the protein structure, while p.P35L, p.L199P, and p.P433L have moderate effects. The p.W202R, p.E352V, p.P433L, and p.R484L variants showed residual 21OH activity consistent with the simple virilizing phenotype. The p.P35L and p.L199P variants showed partial 21OH efficiency associated with the non-classical phenotype. Additionally, p.W202R, p.E352V, and p.R484L also modified the protein expression level. We have determined how the selected CYP21A2 gene mutations affect the 21OH activity through structural and activity alteration contributing to the future diagnosis and management of CYP21A2 deficiency.

Novel frameshift variant of the CFTR gene: S511Lfs*2 from phenotype to molecular predictions.

Cystic fibrosis (CF) is a genetic disease caused by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. There are over 2,000 different pathogenic and non-pathogenic variants described in association with a broad clinical heterogeneity. In this work, we identified a novel variant S511Lfs*2 in CFTR gene that has not been reported in patients with CF. The patient was a female genotyped with c.1000C>T (legacy name: R334W) variant (pathogenic, CF-causing) and the novel variant (S511Lfs*2). We verified the amino acid sequence, the protein structure, and predicted the pathogenicity employing computational analysis. Our findings showed that S511Lfs*2 is a frameshift variant and suggest that it is associated with severe CF phenotype, as it leads to a lack of CFTR protein synthesis, and consequently the loss of its functional activity.

A Low-Cost and Simple Genetic Screening for Cystic Fibrosis Provided by the Brazilian Public Health System.

Cystic fibrosis newborn screening was implemented in Brazil by the Public Health System in 2012. Because of cost, only 1 mutation was tested - p.Phe508del. We developed a robust low-cost genetic test for screening 11 CFTR gene mutations with potential use in developing countries.

SARS-CoV-2 laboratory surveillance during the first year of the COVID-19 pandemic in southern Brazil.

BACKGROUND: Brazil has one of the highest numbers of COVID-19 cases and deaths. Rio Grande do Sul (RS) in southern Brazil is one of the leading states in terms of case numbers. As part of the national public health network, the State Central Laboratory (LACEN-RS) changed its routine in 2020 to focus on the diagnosis of COVID-19. This study evaluated the laboratory surveillance of COVID-19 suspected cases analyzed at the LACEN-RS in 2020. METHODS: Viral detection was performed using RT-qPCR in samples from patients with respiratory infection who met the study criteria. Viral RNA was isolated using commercial manual kits or automated extractors, and SARS-CoV-2 RT-qPCR was performed using the Bio-Manguinhos/Rio de Janeiro, IBMP/Paraná, or Allplex 2019-nCoV assay. In total, 360 representative SARS-CoV-2 samples were sequenced using the Illumina platform. RESULTS: In total, 31,197 of 107,578 (positivity rate = 29%) tested positive for SARS-CoV-2. The number of RT-qPCR tests performed per month followed the COVID-19 epidemic curve observed for the state, with peaks in July-August and December. Females accounted for 63% of the samples, whereas the positivity rate was higher among males (33.1% males vs. 26.5% females). The positivity rate was higher in adults aged 50-79 years compared to the overall positivity rate. The majority of cases were observed in the capital, Porto Alegre, and the metropolitan region. Ten distinct lineages were identified, with B.1.1.28, B.1.1.33, and P.2 being the most frequent. CONCLUSIONS: Here, we describe laboratory surveillance of COVID-19 to identify priorities for epidemiological surveillance actions in RS.

Cystic Fibrosis: Systems Biology Analysis from Homozygous p.Phe508del Variant Patients' Samples Reveals Perturbations in Tissue-Specific Pathways.

Cystic fibrosis (CF) is an autosomal recessive disorder, caused by diverse genetic variants for the CF transmembrane conductance regulator (CFTR) protein. Among these, p.Phe508del is the most prevalent variant. The effects of this variant on the physiology of each tissue remains unknown. This study is aimed at predicting cell signaling pathways present in different tissues of fibrocystic patients, homozygous for p.Phe508del. The study involved analysis of two microarray datasets, E-GEOD-15568 and E-MTAB-360 corresponding to the rectal and bronchial epithelium, respectively, obtained from the ArrayExpress repository. Particularly, differentially expressed genes (DEGs) were predicted, protein-protein interaction (PPI) networks were designed, and centrality and functional interaction networks were analyzed. The study reported that p.Phe508del-mutated CFTR-allele in homozygous state influenced the whole gene expression in each tissue differently. Interestingly, gene ontology (GO) term enrichment analysis revealed that only "neutrophil activation" was shared between both tissues; however, nonshared DEGs were grouped into the same GO term. For further verification, functional interaction networks were generated, wherein no shared nodes were reported between these tissues. These results suggested that the p.Phe508del-mutated CFTR-allele in homozygous state promoted tissue-specific pathways in fibrocystic patients. The generated data might further assist in prediction diagnosis to define biomarkers or devising therapeutic strategies.

Cystic Fibrosis: A Simple and Customized Strategy for Genetic Screening Able to Detect Over 90% of Identified Mutated Alleles in Brazilian Newborns.

INTRODUCTION: The incorporation of molecular genetic testing into cystic fibrosis (CF) screening programs increases the specificity of the diagnostic strategy and has the potential to decrease the rate of false- positive results. In this sense, our objective was to develop a genotyping assay that could detect 25 pathogenic variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene with high sensitivity and that could be incorporated into the routine of newborn screening, complementing the current existing protocol used in our public health institution. METHODS: A mini-sequencing assay was standardized using single-base extension in a previously genotyped control sample. This strategy was validated in a Brazilian cohort of CF patients by Sanger sequencing. RESULTS: The inclusion of the 25 variants in the current newborn screening program increased the identification rates of two alleles from 33 to 52.43% in CF patients. This new approach was able to detect a total of 37 variants, which represents 93.01% of all mutated alleles described in the last CF Brazilian Register. CONCLUSIONS: Mini-sequencing for the simultaneous detection of 25 CFTR gene variants improves the screening of Brazilian newborns and decreases the number of inconclusive cases. This method uses minimal hands-on time and is suited for rapid screening, which reduces sample processing costs.

Genetic and phenotypic traits of children and adolescents with cystic fibrosis in Southern Brazil.

OBJECTIVES: To characterize the main identified mutations on cystic fibrosis transmembrane conductance regulator (CFTR) in a group of children and adolescents at a cystic fibrosis center and its association with the clinical and laboratorial characteristics. METHOD: Descriptive cross-sectional study including patients with cystic fibrosis who had two alleles identified with CFTR mutation. Clinical, anthropometrical, laboratorial and pulmonary function (spirometry) data were collected from patients' records in charts and described with the results of the sample genotyping. RESULTS: 42 patients with cystic fibrosis were included in the study. The most frequent mutation was F508del, covering 60 alleles (71.4%). The second most common mutation was G542X (six alleles, 7.1%), followed by N1303K and R1162X mutations (both with four alleles each). Three patients (7.14%) presented type III and IV mutations, and 22 patients (52.38%) presented homozygous mutation for F508del. Thirty three patients (78.6%) suffered of pancreatic insufficiency, 26.2% presented meconium ileus, and 16.7%, nutritional deficit. Of the patients in the study, 59.52% would be potential candidates for the use of CFTR-modulating drugs. CONCLUSIONS: The mutations of CFTR identified more frequently were F508del and G542X. These are type II and I mutations, respectively. Along with type III, they present a more severe cystic fibrosis phenotype. More than half of the sample (52.38%) presented homozygous mutation for F508del, that is, patients who could be treated with Lumacaftor/Ivacaftor. Approximately 7% of the patients (7.14%) presented type III and IV mutations, therefore becoming candidates for the treatment with Ivacaftor.

SARS-CoV-2 laboratory surveillance during the first year of the COVID-19 pandemic in southern Brazil

ABSTRACT Background: Brazil has one of the highest numbers of COVID-19 cases and deaths. Rio Grande do Sul (RS) in southern Brazil is one of the leading states in terms of case numbers. As part of the national public health network, the State Central Laboratory (LACEN-RS) changed its routine in 2020 to focus on the diagnosis of COVID-19. This study evaluated the laboratory surveillance of COVID-19 suspected cases analyzed at the LACEN-RS in 2020. Methods: Viral detection was performed using RT-qPCR in samples from patients with respiratory infection who met the study criteria. Viral RNA was isolated using commercial manual kits or automated extractors, and SARS-CoV-2 RT-qPCR was performed using the Bio-Manguinhos/Rio de Janeiro, IBMP/Paraná, or Allplex 2019-nCoV assay. In total, 360 representative SARS-CoV-2 samples were sequenced using the Illumina platform. Results: In total, 31,197 of 107,578 (positivity rate = 29%) tested positive for SARS-CoV-2. The number of RT-qPCR tests performed per month followed the COVID-19 epidemic curve observed for the state, with peaks in July-August and December. Females accounted for 63% of the samples, whereas the positivity rate was higher among males (33.1% males vs. 26.5% females). The positivity rate was higher in adults aged 50-79 years compared to the overall positivity rate. The majority of cases were observed in the capital, Porto Alegre, and the metropolitan region. Ten distinct lineages were identified, with B.1.1.28, B.1.1.33, and P.2 being the most frequent. Conclusions: Here, we describe laboratory surveillance of COVID-19 to identify priorities for epidemiological surveillance actions in RS.

Development of CYP21A2 Genotyping Assay for the Diagnosis of Congenital Adrenal Hyperplasia.

BACKGROUND: Steroid 21-hydroxylase deficiency due to CYP21A2 gene mutations represents more than 90% of all congenital adrenal hyperplasia cases. This deficiency is screened by measuring levels of 17-hydroxyprogesterone, which may vary, causing false positive or false negative results. In order to assist the diagnosis, molecular methodologies have been employed. This work aimed to perform genotyping assays to detect mutations in the CYP21A2 gene and compare the findings with other population studies. METHODS: The SNaPshot assay was developed to simultaneously detect 12 frequent point mutations in the CYP21A2 gene (p.Arg409Cys, p.Gln319Ter, p.Arg357Trp, p.Leu308PhefsTer6, p.Val237Glu, IVS2-13A/C > G, p.Ile173Asn, p.Pro31Leu, p.Pro454Ser, p.Val282Leu, p.Gly111ValfsTer21 and p.His63Leu). The direct sequencing and multiplex ligation-dependent probe amplification assays were used to confirm point mutations present in the developed method. The latter was also used to search large deletions and gene conversion, complementing the investigation. A total of 166 cases were studied. RESULTS: The SNaPshot assay was successfully developed to detect the 12 mutations. The results of mutation analysis indicated 84 pathogenic alleles in 48 cases, with p.Val282Leu (27.1%) and IVS2-13A/C > G (20.8%) being the most frequently found mutations. Between the findings of this study and those of other South American studies, there were significant differences in frequency for p.Pro31Leu and p.Val282Leu (p < 0.001). A new variant T in IVS2-13A/C > G was identified in two patients via the SNaPshot assay. CONCLUSION: The molecular strategy developed for CYP21A2 gene mutation screening allowed us to detect the principle mutations described around the world. Furthermore, the first Southern Brazilian mutation frequencies concerning the CYP21A2 gene were obtained.

Genetic and phenotypic traits of children and adolescents with cystic fibrosis in Southern Brazil / Características genéticas e fenotípicas de crianças e adolescentes com fibrose cística no Sul do Brasil

ABSTRACT Objectives: To characterize the main identified mutations on cystic fibrosis transmembrane conductance regulator (CFTR) in a group of children and adolescents at a cystic fibrosis center and its association with the clinical and laboratorial characteristics. Method: Descriptive cross-sectional study including patients with cystic fibrosis who had two alleles identified with CFTR mutation. Clinical, anthropometrical, laboratorial and pulmonary function (spirometry) data were collected from patients' records in charts and described with the results of the sample genotyping. Results: 42 patients with cystic fibrosis were included in the study. The most frequent mutation was F508del, covering 60 alleles (71.4%). The second most common mutation was G542X (six alleles, 7.1%), followed by N1303K and R1162X mutations (both with four alleles each). Three patients (7.14%) presented type III and IV mutations, and 22 patients (52.38%) presented homozygous mutation for F508del. Thirty three patients (78.6%) suffered of pancreatic insufficiency, 26.2% presented meconium ileus, and 16.7%, nutritional deficit. Of the patients in the study, 59.52% would be potential candidates for the use of CFTR-modulating drugs. Conclusions: The mutations of CFTR identified more frequently were F508del and G542X. These are type II and I mutations, respectively. Along with type III, they present a more severe cystic fibrosis phenotype. More than half of the sample (52.38%) presented homozygous mutation for F508del, that is, patients who could be treated with Lumacaftor/Ivacaftor. Approximately 7% of the patients (7.14%) presented type III and IV mutations, therefore becoming candidates for the treatment with Ivacaftor.

RESUMO Objetivos: Caracterizar as principais mutações identificadas no cystic fibrosis transmembrane conductance regulator (CFTR) em um grupo de crianças e adolescentes de um centro multidisciplinar de tratamento de fibrose cística e sua associação com características clínicas e laboratoriais. Método: Estudo transversal descritivo que incluiu pacientes com fibrose cística que possuíam dois alelos identificados com mutação no CFTR. Dados clínicos, antropométricos, laboratoriais e de função pulmonar (espirometria) foram coletados de registros em prontuários e descritos com os resultados de genotipagem da amostra. Resultados: Foram incluídos 42 pacientes com fibrose cística. A mutação mais frequente foi a F508del, abrangendo 60 alelos (71,4%). A segunda mutação mais comum foi a G542X (seis alelos, 7,1%), seguida das mutações N1303K e R1162X (ambas com quatro alelos cada uma). Três pacientes (7,14%) apresentaram mutações de classes III e IV, e 22 pacientes (52,38%), homozigose para F508del. Trinta e três pacientes (78,6%) tinham insuficiência pancreática, 11 (26,2%) apresentaram íleo meconial e sete (16,7%) déficit nutricional. Dos pacientes do estudo, 59,52% seriam potenciais candidatos ao uso de fármacos moduladores de CFTR. Conclusões: As mutações do CFTR identificadas com mais frequência foram F508del e G542X, as quais são mutações pertencentes às classes II e I, respectivamente, e que, juntamente à classe III, conferem um fenótipo de fibrose cística com mais gravidade. Mais da metade (52,38%) da amostra apresentava F508del em homozigose, população candidata ao novo tratamento com Lumacaftor/Ivacaftor. Aproximadamente 7% dos pacientes apresentavam mutações de classes III e IV, sendo candidatos ao tratamento com Ivacaftor.