Estudio genético de inmunodeficiencias primarias: Desarrollo e implementación de algoritmos diagnósticos

Abstract

Primary immunodeficiencies (PID) are a group of more than 350, mainly monogenic, rare diseases characterised by the deficiency or dysregulation of one or more components of the immune system. They can sometimes be life threatening and hematopoietic stem cell transplantation may be the only curative therapy. In this context, the existence of centres which are specialized in the comprehensive diagnosis and treatment of these pathologies is of high importance and the detection of the genetic basis of the disease is an essential part of the process. Technical advances in the field of genetics over the last decade have resulted in a revolution in molecular genetics diagnosis. In PID, next generation sequencing (NGS) has marked a new era, leading to not only the description of nearly 150 new entities from 2011 until now but, also to significantly improve the diagnostic rate. Thus, the acquisition and correct management of this technology is imperative in centres that are focused on the diagnosis of these pathologies. The first part of this work reflects the performance and application, in a PID diagnostic centre, of a custom designed NGS gene panel and other complementary methodologies such as MLPA (Multiplex Ligation Probe Amplification), CGH- (Comparative Genome Hybridization) or SNP (Single Nucleotide Polymorphism) arrays, RT-PCR (Retro-transcriptase Polymerase Chain Reaction), flow cytometry for protein expression evaluation or functional assays. The use of these technologies has enabled the creation of diagnostic algorithms which are exclusive to the suspected mutation and/or the particular characteristics of the suspected gene or group of genes. Thus, this work provides a strategical guide for the routine genetic diagnosis of PID. The second part of this thesis is focused in the description of two novel PID (IRF4 deficiency and IRF9 deficiency), identified through the implementation of NGS. The clinical, immunological, histological and finally genetic characterisation of the three affected individuals and first degree relatives is described.