Frequency of low-level and high-level mosaicism in sporadic retinoblastoma: genotype-phenotype relationships.

Somatic mutational mosaicism is a common feature of monogenic genetic disorders, particularly in diseases such as retinoblastoma, with high rates of de novo mutations. The detection and quantification of mosaicism is particularly relevant in these diseases, since it has important implications for genetic counseling, patient management, and probably also on disease onset and progression. In order to assess the rate of somatic mosaicism (high- and low-level mosaicism) in sporadic retinoblastoma patients, we analyzed a cohort of 153 patients with sporadic retinoblastoma using ultra deep next-generation sequencing. High-level mosaicism was detected in 14 out of 100 (14%) bilateral patients and in 11 out of 29 (38%) unilateral patients in whom conventional Sanger sequencing identified a pathogenic mutation in blood DNA. In addition, low-level mosaicism was detected in 3 out of 16 (19%) unilateral patients in whom conventional screening was negative in blood DNA. Our results also reveal that mosaicism was associated to delayed retinoblastoma onset particularly in unilateral patients. Finally we compared the level of mosaicism in different tissues to identify the best DNA source to identify mosaicism in retinoblastoma patients. In light of these results we recommended analyzing the mosaic status in all retinoblastoma patients using accurate techniques such as next-generation sequencing, even in those cases in which conventional Sanger sequencing identified a pathogenic mutation in blood DNA. Our results suggest that a significant proportion of those cases are truly mosaics that could have been overlooked. This information should be taking into consideration in the management and genetic counseling of retinoblastoma patients and families.

SpainUDP: The Spanish Undiagnosed Rare Diseases Program.

One of the IRDiRC goals for 2017⁻2027 is to achieve definitive diagnosis for rare undiagnosed diseases within one year, as delay in diagnosis remains one of the pending issues in the rare diseases field. The Spanish Undiagnosed Rare Diseases Program (SpainUDP) was created in response to this challenging scenario to cover patients' needs and after seeing the success of the Undiagnosed Diseases Program (UDP) in the USA. SpainUDP offers a multidisciplinary approach to those patients who have long sought a diagnosis without any success. During the first phase of the protocol, undiagnosed cases are sent to SpainUDP by individual patients or families, patient organizations or hospitals. After careful analysis of phenotype, data from sequencing experiments (WES) is processed with a standard pipeline and detailed standardized phenotypic information (mapped to the Human Phenotype Ontology, HPO) is connected to genetic data. In addition, the participation of SpainUDP in international initiatives such as the European projects RD-Connect and Solve RD, the Undiagnosed Diseases Network International (UDNI), and the MatchMaker Exchange (MME) platform, allows the establishment of a global data sharing strategy across multiple projects submitting data to these international initiatives. From the official beginning of the program (at the end of 2015) until early 2018, 147 cases were accepted in SpainUDP. During this time, 37 cases (25%) dropped out the program due to several reasons. The remaining 110 cases are distributed as follows: phenotypic and genotypic (WES) characterization was finished in 30 cases, of which 20 (67%) were diagnosed; 21 cases are pending on variants' validation by Sanger sequencing; in 25 cases, WES is ongoing and 34 cases are being studied for deep phenotypic characterization. In conclusion, SpainUDP aims to achieve a diagnosis following two recommendations of the IRDiRC: the patients' diagnosis in as short a time as possible and the promotion of data sharing (especially genomic) at the international level.

Clinical Outcomes in Duchenne Muscular Dystrophy: A Study of 5345 Patients from the TREAT-NMD DMD Global Database.

BACKGROUND: Recent short-term clinical trials in patients with Duchenne Muscular Dystrophy (DMD) have indicated greater disease variability in terms of progression than expected. In addition, as average life-expectancy increases, reliable data is required on clinical progression in the older DMD population. OBJECTIVE: To determine the effects of corticosteroids on major clinical outcomes of DMD in a large multinational cohort of genetically confirmed DMD patients. METHODS: In this cross-sectional study we analysed clinical data from 5345 genetically confirmed DMD patients from 31 countries held within the TREAT-NMD global DMD database. For analysis patients were categorised by corticosteroid background and further stratified by age. RESULTS: Loss of ambulation in non-steroid treated patients was 10 years and in corticosteroid treated patients 13 years old (p = 0.0001). Corticosteroid treated patients were less likely to need scoliosis surgery (p < 0.001) or ventilatory support (p < 0.001) and there was a mild cardioprotective effect of corticosteroids in the patient population aged 20 years and older (p = 0.0035). Patients with a single deletion of exon 45 showed an increased survival in contrast to other single exon deletions. CONCLUSIONS: This study provides data on clinical outcomes of DMD across many healthcare settings and including a sizeable cohort of older patients. Our data confirm the benefits of corticosteroid treatment on ambulation, need for scoliosis surgery, ventilation and, to a lesser extent, cardiomyopathy. This study underlines the importance of data collection via patient registries and the critical role of multi-centre collaboration in the rare disease field.

Cystic fibrosis mortality trends in Spain among infants and young children: 1981-2004.

UNLABELLED: This paper sought to analyse mortality trends among infants and young children who died with a diagnosis of cystic fibrosis (CF) in Spain, during the period 1981-2004. STUDY DESIGN: Descriptive observational study, using joinpoint regression models. PARTICIPANTS: Data on cystic fibrosis deaths were drawn from the National Statistics Institute (Instituto Nacional de Estadística), which collects data from all death certificates in Spain. During the period 1981-2004, overall CF mortality in Spain decreased by an annual average of 4% in both sexes. A breakdown by age showed that patients under 15 years registered a declining and those over 15 years a rising mortality rate over the study period. Mean and median age at death from CF increased with time, from a median of 4.4 years (males) and 3.8 years (females) in 1981 to 20.1 years (males) and 17.7 years (females) in 2004. The results of this study show that, as in other Western countries, CF is no longer a major cause of death in childhood, and that the challenge now lies in caring for adults who suffer from this disease. The fact that our study was descriptive meant that the reasons for the decrease in CF mortality in Spain could not be identified. Other authors have shown that this decrease is associated with improved treatment for pulmonary complications, better nutritional control and lung transplants.

Genetic approaches in the understanding of Toxic Oil Syndrome.

The Toxic Oil Syndrome (TOS) is a multisystemic disease that occurred in Spain in 1981 due to the ingestion of rapeseed oil denatured with 2% aniline. Female prevalence and the different clinical evolution even inside the same family (similar exposition), pointed to genetic implications. Furthermore, HLA-DR2 was increased in patients dead because of TOS. Th2 activation and eosinophilia implicated immunological mechanisms. For those reasons we firstly decided, to do a genome-wide search by linkage mapping set along the chromosome 6 (where HLA loci are located), to identify loci associated to the TOS development. The design was case-control-matched (n = 328). By this procedure, microsatellite (near to HLA) was related with the patients. After fine-mapping around this marker, we defined four more closely related to TOS-, , and . Secondly, we analysed in 420 patients, the association of these four markers with 14 TOS clinical phenotypes. We demonstrated that alveolar infiltration, liver disease and scleroderma are clearly associated with . As conclusion, we have identified in chromosome 6, a region where are located some genes related with autoimmune diseases, associated with certain TOS phenotypes, pointing out the possible role of autoimmune reactions in the pathogenesis of the disease.

Toxic oil syndrome: genetic restriction and immunomodulatory effects due to adulterated oils in a model of HLA transgenic mice.

Toxic oil syndrome (TOS) was described in Spain in 1981, due to the ingestion of contaminated rapeseed oil denatured with 2% aniline. More than 20,000 persons were affected, causing over 2500 deaths. Immunological findings were: eosinophilia, mRNA for Th2 cytokines (IL-4 and IL-5) in lungs, elevated total IgE and sIL-2R and increase of DR2 HLA class II phenotypic frequency in patients died by TOS. Our objective is to test the genetic restriction found in humans using HLA transgenic mice. Results show that mice expressing human DR2 and DQ6 (both in linkage disequilibrium), had higher percentage of eosinophils (DQ6) and IgE (DR2) than other transgenic mice tested (DR3 and DR4). Also, a Th2 shift was found in DR2 transgenic mice when toxic oil was administered with OVA. This has been corroborated by the IL-5 mRNA expression in 4 out of 6 lung tissues from TOS oil treated BALB/c mice. These data indicate that an immunological response was induced as consequence of the toxic administration. These results correlate with those found in TOS patients and reinforce the implication of genetic restrictions in the acquisition of toxic-mediated disease.

Determination of protein markers in human serum: Analysis of protein expression in toxic oil syndrome studies.

Toxic oil syndrome (TOS) is a disease that appeared in Spain in 1981. It affected more than 20 000 people and produced over 300 deaths in the first 2 years. In this paper, a prospective study on the differences in gene expression in sera between a control versus a TOS-affected population, both originally exposed to the toxic oil, is presented. Differential protein expression was analyzed by two-dimensional electrophoresis (2-DE). Several problems related with serum analysis by 2-DE were addressed in order to improve protein detection in the gel images. Three new commercial systems for albumin depletion were tested to optimize the detection of minor proteins that can be obscured by the presence of a few families of high abundance proteins (albumin, immunoglobulins). Other factors, such as the use of nonionic reductants or the presence of thiourea in the gels, were also tested. From these optimized images, a group of 329 major gel spots was located, matched and compared in serum samples. Thirty-five of these protein spots were found to be under- or overexpressed in TOS patients (> three-fold increase or decrease). Proteins in the differential spots were identified by matrix-assisted laser desorption/ionization-time of flight peptide map fingerprinting and database search. Several haptoglobin isoforms were found to be differentially expressed, showing expression phenotypes that could be related with TOS affection. Haptoglobin phenotypes have been previously reported to have important biological and clinical consequences and have been described as risk factors for several diseases.