Análisis del rendimiento de la secuenciación del exoma clínico en hipogonadismo hipogonadotropo congénito teniendo en cuenta el grado de alteración del olfato.

Introduction: Congenital hypogonadotropic hypogonadism (CHH) can present alone or in association with anosmia or other congenital malformations. More than 30 genes have been identified as being involved in the pathogenesis of CHH with different patterns of inheritance, and the increasing availability of next generation sequencing (NGS) has increased the diagnostic yield. Methods: We analysed the diagnostic yield of NGS in patients with CHH using the clinical exome filtered with virtual panels. We also assessed whether designing panels based on the presence/absence of microsmia increased the diagnostic yield. Results: The use of a 34-gene virtual panel confirmed the diagnosis of CHH in 5 out of 9 patients (55%). In 2 out of 9 (22%), the findings were inconclusive. Applying the presence/absence of microsmia criterion to choose genes for analysis did not improve the diagnostic yield. Conclusions: The approach to the genetic study of patients with CHH varies depending on the resources of each healthcare facility, so the sensitivity of testing may vary substantially depending on whether panels, clinical exome sequencing or whole exome sequencing (WES) are used. The analysis of every genes related to CHH regardless of the presence/absence of microsmia seems to be the best approach.Introducción: El hipogonadismo hipogonadotropo congénito (HHC) puede presentarse de manera aislada o acompñado de anosmia o de malformaciones congénitas. Más de 30 genes han sido implicados en la patogénesis de HHC; además, se han descrito varios patrones de herencia asociados a esta entidad. La creciente disponibilidad de técnicas de secuenciación masiva (NGS) ha permitido que aumente el rendimiento diagnóstico del estudio de esta patología. Pacientes y métodos: Evaluamos el rendimiento diagnóstico del estudio mediante NGS de pacientes con HHC, usando la secuenciación del exoma clínico filtrado por paneles virtuales. Además, se analizó si el diseño de estos paneles, basándose en la presencia/ausencia de microsmia/anosmia aumentaban este rendimiento diagnóstico. Resultados: Usando un panel virtual compuesto de 34 genes pudimos confirmar el diagnóstico de HHC en cinco de nueve pacientes (55%). En dos de nueve individuos (22%) estudiados se obtuvieron resultados no concluyentes. La ausencia/presencia de microsmia para la elección de genes a estudiar no mejora el rendimiento diagnóstico. Conclusiones: El abordaje del estudio genético de pacientes con HHC puede variar en función de las técnicas disponibles en cada centro, por lo que la sensibilidad del test utilizado variará, dependiendo si se utiliza secuenciación de paneles, exoma clínico o exoma completo. El análisis de todos los genes relacionados con HHC independientemente de la presencia/ausencia de microsmia pareciera el abordaje con mejor rendimiento.This study was supported by the Department of Genomic Medicine of the Universidad Autónoma de Madrid-Fundación Jiménez Díaz (file 081800)

Recessive dystrophic epidermolysis bullosa: the origin of the c.6527insC mutation in the Spanish population

This work was supported by grants from the Spanish Ministry of Science and Innovation (MICINN) (SAF2007-61019 and SAF 2010-16976), INTRA ⁄08 ⁄714.1 and INTRA ⁄09 ⁄758 from the Biomedical Network Research Centre on Rare Diseases (CIBERER) and S2010 ⁄BMD-2420 (CELLCAM) from Comunidad de Madrid

A prevalent mutation with founder effect in Spanish recessive dystrophic epidermolysis bullosa families

Background: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a genodermatosis caused by more than 500 different mutations in the COL7A1 gene and characterized by blistering of the skin following a minimal friction or mechanical trauma. The identification of a cluster of RDEB pedigrees carrying the c.6527insC mutation in a specific area raises the question of the origin of this mutation from a common ancestor or as a result of a hotspot mutation. The aim of this study was to investigate the origin of the c.6527insC mutation. Methods: Haplotypes were constructed by genotyping nine single nucleotides polymorphisms (SNPs) throughout the COL7A1 gene. Haplotypes were determined in RDEB patients and control samples, both of Spanish origin. Results: Sixteen different haplotypes were identified in our study. A single haplotype cosegregated with the c.6527insC mutation. Conclusion: Haplotype analysis showed that all alleles carrying the c.6527insC mutation shared the same haplotype cosegregating with this mutation (CCGCTCAAA_6527insC), thus suggesting the presence of a common ancestor.This work was supported in part by grants from Spanish Ministry of Science and Innovation (SAF2007-61019 and SAF2010-16976) and INTRA/08/714 from Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER)

Mutation analysis of 272 Spanish families affected by autosomal recessive retinitis pigmentosa using a genotyping microarray

Contains fulltext : 89342.pdf (publisher's version ) (Open Access)PURPOSE: Retinitis pigmentosa (RP) is a genetically heterogeneous disorder characterized by progressive loss of vision. The aim of this study was to identify the causative mutations in 272 Spanish families using a genotyping microarray. METHODS: 272 unrelated Spanish families, 107 with autosomal recessive RP (arRP) and 165 with sporadic RP (sRP), were studied using the APEX genotyping microarray. The families were also classified by clinical criteria: 86 juveniles and 186 typical RP families. Haplotype and sequence analysis were performed to identify the second mutated allele. RESULTS: At least one-gene variant was found in 14% and 16% of the juvenile and typical RP groups respectively. Further study identified four new mutations, providing both causative changes in 11% of the families. Retinol Dehydrogenase 12 (RDH12) was the most frequently mutated gene in the juvenile RP group, and Usher Syndrome 2A (USH2A) and Ceramide Kinase-Like (CERKL) were the most frequently mutated genes in the typical RP group. The only variant found in CERKL was p.Arg257Stop, the most frequent mutation. CONCLUSIONS: The genotyping microarray combined with segregation and sequence analysis allowed us to identify the causative mutations in 11% of the families. Due to the low number of characterized families, this approach should be used in tandem with other techniques

A prevalent mutation with founder effect in Spanish Recessive Dystrophic Epidermolysis Bullosa families

<p>Abstract</p> <p>Background</p> <p>Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a genodermatosis caused by more than 500 different mutations in the <it>COL7A1 </it>gene and characterized by blistering of the skin following a minimal friction or mechanical trauma.</p> <p>The identification of a cluster of RDEB pedigrees carrying the c.6527insC mutation in a specific area raises the question of the origin of this mutation from a common ancestor or as a result of a hotspot mutation. The aim of this study was to investigate the origin of the c.6527insC mutation.</p> <p>Methods</p> <p>Haplotypes were constructed by genotyping nine single nucleotides polymorphisms (SNPs) throughout the <it>COL7A1 </it>gene. Haplotypes were determined in RDEB patients and control samples, both of Spanish origin.</p> <p>Results</p> <p>Sixteen different haplotypes were identified in our study. A single haplotype cosegregated with the c.6527insC mutation.</p> <p>Conclusion</p> <p>Haplotype analysis showed that all alleles carrying the c.6527insC mutation shared the same haplotype cosegregating with this mutation (<b><it>CCGCTCAAA_6527insC</it></b>), thus suggesting the presence of a common ancestor.</p

An evaluation of pipelines for DNA variant detection can guide a reanalysis protocol to increase the diagnostic ratio of genetic diseases

Clinical exome (CE) sequencing has become a first-tier diagnostic test for hereditary diseases; however, its diagnostic rate is around 30–50%. In this study, we aimed to increase the diagnostic yield of CE using a custom reanalysis algorithm. Sequencing data were available for three cohorts using two commercial protocols applied as part of the diagnostic process. Using these cohorts, we compared the performance of general and clinically relevant variant calling and the efficacy of an in-house bioinformatic protocol (FJD-pipeline) in detecting causal variants as compared to commercial protocols. On the whole, the FJD-pipeline detected 99.74% of the causal variants identified by the commercial protocol in previously solved cases. In the unsolved cases, FJD-pipeline detects more INDELs and non-exonic variants, and is able to increase the diagnostic yield in 2.5% and 3.2% in the re-analysis of 78 cancer and 62 cardiovascular cases. These results were considered to design a reanalysis, filtering and prioritization algorithm that was tested by reassessing 68 inconclusive cases of monoallelic autosomal recessive retinal dystrophies increasing the diagnosis by 4.4%. In conclusion, a guided NGS reanalysis of unsolved cases increases the diagnostic yield in genetic disorders, making it a useful diagnostic tool in medical geneticsWe want to thank the participants for consenting to the use of their data for the study. We would like to thank all technical staff in the genetics service of the Fundación Jiménez Díaz University Hospital for conducting the sequencing and segregation analysis. We also thank Oliver Shaw (IIS-FJD) for editorial assistance. This work was supported by the Instituto de Salud Carlos III (ISCIII) of the Spanish Ministry of Health (FIS; PI16/00425, PI19/00321, PI18/00579 and PI20/00851), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER, 06/07/0036), IIS-FJD BioBank (PT13/0010/0012), Comunidad de Madrid (CAM, RAREGenomics Project, B2017/BMD-3721), Ramón Areces Foundation (4019/012), Conchita Rábago Foundation, and the University Chair UAM-IIS-FJD of Genomic Medicine. R.R. is supported by a postdoctoral fellowship of the Comunidad de Madrid (2019-T2/BMD-13714), L.d.l.F. is supported by the platform technician contract of ISCIII (CA18/00017), IPR is supported by a PhD studentship from the predoctoral program from ISCIII (FI17/ 00192), I.F.I. is supported by a grant from the Comunidad de Madrid (CAM, PEJ-2017- AI/BMD7256), G.N.M. is supported by a grant from the Comunidad de Madrid (PEJ2020-AI/BMD-18610), A.D. is supported by a PhD studentship from the predoctoral program from ISCIII (FI18/00123), B.A. is supported by a Juan Rodes program from ISCIII (JR17/00020), C.R. is supported by a PhD studentship from the Conchita Rabago Foundation and PM and MC are supported by a Miguel Servet program contract from ISCIII (CP16/00116 and CPII17/00006, respectively). The funders played no role in study design, data collection, data analysis, manuscript preparation, and/or publication decision

Estudio genético en familias españolas afectadas de retinopatías hereditarias Retinosis Pigmentaria Autosómica Dominante (ADRP). Distrofia Macular Autosómica Dominante (ADDM) y Coroideremia (CHM)

Tesis doctoral inédita leida en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de lectura: 13-11-199

Ellis-van Creveld syndrome in a fetus with rhizomelia and polydactyly. Report of a case diagnosed by genetic analysis, and correlation with pathological andradiologic findings

Ellis-van Creveld syndrome is an autosomal recessive disorder mainly characterized by a disproportionate limb dwarfism, chondroectodermal dysplasia, congenital heart disease, postaxial polydactyly, and dysplastic fingernails and teeth. Only 300 cases have been published worldwide. We report a 21-week fetus with rhizomelia and polydactyly detected. Gross photographs, radiologic studies and pathological study were performed leading to the clinico-pathological suspicion of EvC. DNA from fresh fetal tissue was extracted for sequencing the EVC and EVC2 genes. p.W215X and p.R677X mutations were identified in the EVC2 gene in the fetal sample. Parental sample analysis showed the p.W215X mutation to be inherited from the mother and the p.R677X mutation from the father. The clinical information is essential not only to arrive at a correct diagnosis in fetuses with pathologic ultrasound findings, but also to offer a proper genetic counseling to the parents and their relatives.This work has been sponsored by Fundacion Ramón Areces (4715/001) and CIBERER from the Instituto de Salud Carlos III (06/07/0036).Peer Reviewe