Translational Bioinformatics Applied to the Study of Complex Diseases.

Translational Bioinformatics (TBI) is defined as the union of translational medicine and bioinformatics. It emerges as a major advance in science and technology by covering everything, from the most basic database discoveries, to the development of algorithms for molecular and cellular analysis, as well as their clinical applications. This technology makes it possible to access the knowledge of scientific evidence and apply it to clinical practice. This manuscript aims to highlight the role of TBI in the study of complex diseases, as well as its application to the understanding and treatment of cancer. An integrative literature review was carried out, obtaining articles through several websites, among them: PUBMED, Science Direct, NCBI-PMC, Scientific Electronic Library Online (SciELO), and Google Academic, published in English, Spanish, and Portuguese, indexed in the referred databases and answering the following guiding question: "How does TBI provide a scientific understanding of complex diseases?" An additional effort is aimed at the dissemination, inclusion, and perpetuation of TBI knowledge from the academic environment to society, helping the study, understanding, and elucidating of complex disease mechanics and their treatment.

Gene-Based Association Testing of Dichotomous Traits With Generalized Functional Linear Mixed Models Using Extended Pedigrees: Applications to Age-Related Macular Degeneration.

Genetics plays a role in age-related macular degeneration (AMD), a common cause of blindness in the elderly. There is a need for powerful methods for carrying out region-based association tests between a dichotomous trait like AMD and genetic variants on family data. Here, we apply our new generalized functional linear mixed models (GFLMM) developed to test for gene-based association in a set of AMD families. Using common and rare variants, we observe significant association with two known AMD genes: CFH and ARMS2. Using rare variants, we find suggestive signals in four genes: ASAH1, CLEC6A, TMEM63C, and SGSM1. Intriguingly, ASAH1 is down-regulated in AMD aqueous humor, and ASAH1 deficiency leads to retinal inflammation and increased vulnerability to oxidative stress. These findings were made possible by our GFLMM which model the effect of a major gene as a fixed mean, the polygenic contributions as a random variation, and the correlation of pedigree members by kinship coefficients. Simulations indicate that the GFLMM likelihood ratio tests (LRTs) accurately control the Type I error rates. The LRTs have similar or higher power than existing retrospective kernel and burden statistics. Our GFLMM-based statistics provide a new tool for conducting family-based genetic studies of complex diseases. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.

Exploring a Region on Chromosome 8p23.1 Displaying Positive Selection Signals in Brazilian Admixed Populations: Additional Insights Into Predisposition to Obesity and Related Disorders.

We recently reported a deviation of local ancestry on the chromosome (ch) 8p23.1, which led to positive selection signals in a Brazilian population sample. The deviation suggested that the genetic variability of candidate genes located on ch 8p23.1 may have been evolutionarily advantageous in the early stages of the admixture process. In the present work, we aim to extend the previous work by studying additional Brazilian admixed individuals and examining DNA sequencing data from the ch 8p23.1 candidate region. Thus, we inferred the local ancestry of 125 exomes from individuals born in five towns within the Southeast region of Brazil (São Paulo, Campinas, Barretos, and Ribeirão Preto located in the state of São Paulo and Belo Horizonte, the capital of the state of Minas Gerais), and compared to data from two public Brazilian reference genomic databases, BIPMed and ABraOM, and with information from the 1000 Genomes Project phase 3 and gnomAD databases. Our results revealed that ancestry is similar among individuals born in the five Brazilian towns assessed; however, an increased proportion of sub-Saharan African ancestry was observed in individuals from Belo Horizonte. In addition, individuals from the five towns considered, as well as those from the ABRAOM dataset, had the same overrepresentation of Native-American ancestry on the ch 8p23.1 locus that was previously reported for the BIPMed reference sample. Sequencing analysis of ch 8p23.1 revealed the presence of 442 non-synonymous variants, including frameshift, inframe deletion, start loss, stop gain, stop loss, and splicing site variants, which occurred in 24 genes. Among these genes, 13 were associated with obesity, type II diabetes, lipid levels, and waist circumference (PRAG1, MFHAS1, PPP1R3B, TNKS, MSRA, PRSS55, RP1L1, PINX1, MTMR9, FAM167A, BLK, GATA4, and CTSB). These results strengthen the hypothesis that a set of variants located on ch 8p23.1 that result from positive selection during early admixture events may influence obesity-related disease predisposition in admixed individuals of the Brazilian population. Furthermore, we present evidence that the exploration of local ancestry deviation in admixed individuals may provide information with the potential to be translated into health care improvement.

The Master of Puppets: Pleiotropy of PDGFRB and its Relationship to Multiple Diseases.

The platelet-derived growth factor receptor beta (PDGFRB) gene is involved in proliferative and developmental processes in mammals. Variations in this gene lead to several different syndromic conditions, such as infantile myofibromatosis I, sporadic port-wine stain, primary familial brain calcification, and the Penttinen and overgrowth syndromes. Our objective was to investigate PDGFRB's genetic relationship to clinical conditions and evaluate the protein interactions using GeneNetwork, GeneMANIA, and STRING network databases. We have evidenced the gene's pleiotropy through its many connections and its link to syndromic conditions. Therefore, PDGFRB may be an important therapeutic target for treating such conditions.

Integración de la Bioinformática en la caracterización Clínica y Genómica de Retinitis Pigmentosa, Síndrome de Noonan y Síndrome de Retraso Mental Martin-Probs, en un mismo individuo. Reporte de un Caso / Integration of Bioinformatics in the Clinical and Genomic Characterization of Retinitis Pigmentosa, Noonan Syndrome and Martin-Probs Mental Retardation Syndrome, in the Same Individual. Case report

Introducción: El avance en las técnicas bioinformáticas ha permitido realizar acercamientos y mejoras en los diagnósticos clínicos, correlacionando genotipo ­ fenotipo y permitiendo el acercamiento a una terapia personalizada. Objetivo: Realizar mediante técnicas bioinformáticas, la caracterización molecular y de expresión génica de una paciente con manifestaciones clínicas (dismorfias, retraso en el desarrollo) de una enfermedad compleja (poligénica). Materiales y métodos: Se realizó la secuenciación de exoma completo a partir de una muestra de sangre periférica. Se analizaron los datos obtenidos mediante análisis in-sílico, utilizando programas como SIFT, Mutation Tester, UMD y Provean, para determinar la significancia clínica de variantes encontradas; además se usó programa GeneMania para determinar las interacciones génicas. Resultados:Se encontraron 3 variantes en los genes SEMA4A, PTPN11 y RAB40A, asociados a Retinitis pigmentosa 35, Síndrome de Noonan y Sindrome de retraso mental Martin-Probs, respectivamente; encontrando según los softwares predictores, en el primer caso un significado clínico aparentemente benigno, y en los dos últimos genes un significado clínico patogénico. El análisis de redes génicas reveló alteraciones en funciones biológicas como la señalización mediada por fosfatidilinositol, respuesta al factor del crecimiento fibroblástico, vía de señalización de neutrofina y la morfogénesis de vasos sanguíneo que permitieron explicar gran parte de la sintomatología observada. Conclusión: El análisis personalizado de las patologías complejas mediante el uso de la clínica, herramientas genómicas y bioinformaticas han permitido un avance significativo en las técnicas para el procesamiento y análisis de datos, beneficiando los estudios científicos que permiten el acercamiento a un correcto diagnóstico y adecuada consejería genética.

Introduction: Advances in bioinformatics techniques have allowed approaches and improvements in clinical diagnoses, correlating genotype - phenotype and allowing the approach to personalized therapy. Objective: In order to perform the molecular characterization and gene expression in a patient with complex clinical manifestations through bioinformatics techniques, complete exome sequencing was performed by a peripheral blood sample to a woman with facial dysmorphisms and developmental disorders. Material and methods: We analyzed the data obtained by in-silico analysis, using programs such as SIFT, Mutation Tester, UMD and Provean, to determine the clinical significance of the found variants and GeneMania program was used to determine gene interactions. Results: 3 variants were found in the genes SEMA4A, PTPN11 and RAB40A, associated with Retinitis pigmentosa 35, Noonan Syndrome and Mental Retardation Syndrome Martin-Probs, respectively; according to the predictive softwares, in the first case an apparently benign clinical meaning, and in the last two genes a clinical pathogenic meaning. The analysis of gene networks revealed alterations in biological functions such as signaling mediated by phosphatidylinositol, response to the fibroblastic growth factor, neutrophin signaling pathway and blood vessel morphogenesis that allowed us to explain a large part of the observed symptomatology. Conclusion: The personalized analysis of complex pathologies through the use of clinical, genomic and bioinformatic tools has allowed a significant advance in techniques for processing and analyzing data, benefiting scientific studies that allow the approach to a correct diagnosis and adequate genetic counseling.

CLOCK Polymorphisms in Attention-Deficit/Hyperactivity Disorder (ADHD): Further Evidence Linking Sleep and Circadian Disturbances and ADHD.

Circadian and sleep disorders, short sleep duration, and evening chronotype are often present in attention-deficit/hyperactivity disorder (ADHD). CLOCK, considered the master gene in the circadian rhythm, has been explored by few studies. Understanding the relationship between ADHD and CLOCK may provide additional information to understand the correlation between ADHD and sleep problems. In this study, we aimed to explore the association between ADHD and CLOCK, using several genetic markers to comprehensively cover the gene extension. A total of 259 ADHD children and their parents from a Brazilian clinical sample were genotyped for eight single nucleotide polymorphisms (SNPs) in the CLOCK locus. We tested the individual markers and the haplotype effects using binary logistic regression. Binary logistic and linear regressions considering ADHD symptoms among ADHD cases were conducted as secondary analysis. As main result, the analysis showed a risk effect of the G-A-T-G-G-C-G-A (rs534654, rs1801260, rs6855837, rs34897046, rs11931061, rs3817444, rs4864548, rs726967) haplotype on ADHD. A suggestive association between ADHD and rs534654 was observed. The results suggest that the genetic susceptibility to circadian rhythm attributed to the CLOCK gene may play an important role on ADHD.

Long Non-Coding RNAs in Multifactorial Diseases: Another Layer of Complexity.

Multifactorial diseases such as cancer, cardiovascular conditions and neurological, immunological and metabolic disorders are a group of diseases caused by the combination of genetic and environmental factors. High-throughput RNA sequencing (RNA-seq) technologies have revealed that less than 2% of the genome corresponds to protein-coding genes, although most of the human genome is transcribed. The other transcripts include a large variety of non-coding RNAs (ncRNAs), and the continuous generation of RNA-seq data shows that ncRNAs are strongly deregulated and may be important players in pathological processes. A specific class of ncRNAs, the long non-coding RNAs (lncRNAs), has been intensively studied in human diseases. For clinical purposes, lncRNAs may have advantages mainly because of their specificity and differential expression patterns, as well as their ideal qualities for diagnosis and therapeutics. Multifactorial diseases are the major cause of death worldwide and many aspects of their development are not fully understood. Recent data about lncRNAs has improved our knowledge and helped risk assessment and prognosis of these pathologies. This review summarizes the involvement of some lncRNAs in the most common multifactorial diseases, with a focus on those with published functional data.

Chronic meningococcemia: a rare presentation of meningococcal disease: case report.

Chronic meningococcemia is a rare clinical presentation within the spectrum of infections due to Neisseria -en.jpg-en.jpgmeningitidis, which was first described in 1902. It is defined as a chronic and benign meningococcal bacteremia without meningeal signs or symptoms with at least one week's duration, characterized by intermittent or continuous fever, polymorphic cutaneous rash, and migratory arthropathy. The incidence is believed to be around 1:200,000 inhabitants. It affects predominantly young people and adults, and it is equally distributed between genders. Diagnosis may be challenging in the early stages of the disease because of the difficulty in isolating Neisseria -en.jpg-en.jpgmeningitidis (it reaches 74% of positivity in advanced stages). Recently, the use of PCR for detecting Neisseria -en.jpg-en.jpgsp antigen in skin biopsies specimens has been considered for those culture-negative cases. The authors report a case of a 54-year-old female patient who sought medical attention for a five-day fever followed by arthralgia and skin lesions predominantly in the lower limbs. The patient progressed to a toxemic clinical status that improved after the administration of antibiotic therapy, which consisted of oxacillin and ceftriaxone. The diagnosis of chronic meningococcemia was performed after the isolation of Neisseria meningitidis in two different blood sample cultures. This is, to our knowledge, the first case of chronic meningococcemia described in Brazil (up to the writing of this report).

Estudios de asociación mediante rastreo genómico y su contribución en la genética del asma / Genome-wide association studies (gwas) and its contribution to the genetic of asthma

A pesar de todos los esfuerzos realizados por más de una década, las bases genéticas de muchas enfermedades comunes y complejas aún siguen siendo desconocidas, sin desmeritar los notables avances que se han logrado con los estudios de ligamiento en familias y de asociación con genes candidatos. Recientemente, el desarrollo de metodologías más robustas, como los estudios de asociación con rastreos genómicos (GWAs), ha permitido replicar asociaciones ya reportadas y a la vez descubrir nuevos genes posiblemente asociados. Los GWAs se basan en la utilización de un número considerable de marcadores genéticos tipo SNPs o STRs, los cuales son detectados con el propósito de encontrarlos asociados con la aparición y/o desarrollo de ciertas enfermedades. Teniendo en cuenta el gran impacto que actualmente tienen los GWAs como herramienta genética en la búsqueda de asociaciones, se hace una revisión teórica acerca del diseño e interpretación de los resultados de los mismos y su contribución en el asma y fenotipos relacionados.

Despite all the efforts of more than a decade, the genetic basis of many common and complex diseases are still unknown, without demerit the remarkable progress that has been made with the linkage studies in families and association studies of candidate genes. Recently, development of more robust methodologies, like genome-wide associations studies (GWAs), has allowed to replicate previously reported associations and at the same time discovers new possibly associated genes. The GWAs are based on the use of a considerable number of genetic markers like SNPs or STRs which are searched in order to of associate them with the appearance or development of certain diseases. Given the large current impact of the GWAs as genetic tool in the search of associations this is a theoretical review on the design and interpretation of results and contribution of GWAs in asthma and related phenotypes.

Identificación de genes causales y de susceptibilidad para enfermedades de herencia mendeliana y compleja / Identification of susceptibility and causing genes for mendelian and complex diseases

Los factores genéticos participan en la etiología de la mayoría de las enfermedades comunes en la población. Las enfermedades en las que participan factores genéticos pueden ser clasificadas en varias categorías y de acuerdo con las características que presenten, se pueden utilizar distintas estrategias metodológicas para identificar los genes participantes. En la mayoría de las enfermedades con un patrón de herencia mendeliana, se han podido identificar las mutaciones causales de la enfermedad. En las enfermedades complejas, esta búsqueda ha sido menos exitosa a pesar de ser las más frecuentes en la población. Encontrar genes de susceptibilidad es importante no solo para entender el mecanismo de acción de la enfermedad, sino que podría contribuir en el desarrollo de medicamentos más eficaces para el tratamiento, conocer los factores ambientales y desarrollar intervenciones preventivas y, en algunos casos, la aplicación de terapia génica.

Genetic factors are involved in the etiology of most common diseases and traits present in populations. Different methodological approaches can be utilized to determine genes involvedaccording to their genetic features in diseases. In the majority of conditions that follow a simple Mendelian pattern culprit genetic mutations have been identified. Conversely complex traits that are most common in the population are also the most difficult to identify. Finding these genes is crutial no just to clarify the pathophysiology of these common diseases but also to identifyenvironmental factors involved and to improve their treatment, including in some specific cases gene therapy.