Distribution of human beta-defensin polymorphisms in various control and cystic fibrosis populations.

Abstract Human beta defensins contribute to the first line of defense against infection of the lung. Polymorphisms in these genes are therefore potential modifiers of the severity of lung disease in cystic fibrosis. Polymorphisms were sought in the human beta-defensin genes DEFB1, DEFB4, DEFB103A, and DEFB104 in healthy individuals and cystic fibrosis (CF) patients living in various European countries. DEFB1, DEFB4, and DEFB104 were very polymorphic, but DEFB103A was not. Within Europe, differences between control populations were found for some of the frequent polymorphisms in DEFB1, with significant differences between South-Italian and Czech populations. Moreover, frequent polymorphisms located in DEFB4 and DEFB104 were not in Hardy Weinberg equilibrium in all populations studied, while those in DEFB1 were in Hardy Weinberg equilibrium. Sequencing of a monochromosomal chromosome 8 mouse-human hybrid cell line revealed signals for multiple alleles for some loci in DEFB4 and DEFB104, but not for DEFB1. This indicated that more than one DEFB4 and DEFB104 gene was present on this chromosome 8, in agreement with recent findings that DEFB4 and DEFB104 are part of a repeat region. Individual DEFB4 and DEFB104 PCR amplification products of various samples were cloned and sequenced. The results showed that one DNA sample could contain more than two haplotypes, indicating that the various repeats on one chromosome were not identical. Given the higher complexity found in the genomic organization of the DEFB4 and DEFB104 genes, association studies with CF lung disease severity were performed only for frequent polymorphisms located in DEFB1. No association with the age of first infection by Pseudomonas aeruginosa or with the FEV1 percentage at the age of 11-13 years could be found

Novel GAA Variants and Mosaicism in Pompe Disease Identified by Extended Analyses of Patients with an Incomplete DNA Diagnosis

Pompe disease is a metabolic disorder caused by a deficiency of the glycogen-hydrolyzing lysosomal enzyme acid α-glucosidase (GAA), which leads to progressive muscle wasting. This autosomal-recessive disorder is the result of disease-associated variants located in the GAA gene. In the present study, we performed extended molecular diagnostic analysis to identify novel disease-associated variants in six suspected Pompe patients from four different families for which conventional diagnostic assays were insufficient. Additional assays, such as a generic-splicing assay, minigene analysis, SNP array analysis, and targeted Sanger sequencing, allowed the identification of an exonic deletion, a promoter deletion, and a novel splicing variant located in the 5′ UTR. Furthermore, we describe the diagnostic process for an infantile patient with an atypical phenotype, consisting of left ventricular hypertrophy but no signs of muscle weakness or motor problems. This led to the identification of a genetic mosaicism for a very severe GAA variant caused by a segmental uniparental isodisomy (UPD). With this study, we aim to emphasize the need for additional analyses to detect new disease-associated GAA variants and non-Mendelian genotypes in Pompe disease where conventional DNA diagnostic assays are insufficient

Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice

It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings

The Return of Individual Research Findings in Pediatric Genetic Research

The combination of the issue of return of individual genetic results/incidental findings and paediatric biobanks is not much discussed in ethical literature. The traditional arguments pro and con return of such findings focus on principles such as respect for persons, autonomy and solidarity. Two dimensions have been distilled from the discussion on return of individual results in a genetic research context: the respect for a participant's autonomy and the duty of the researcher. Concepts such as autonomy and solidarity do not fit easily in the discussion when paediatric biobanks are concerned. Although parents may be allowed to enrol children in minimal risk genetic research on stored tissue samples, they should not be given the option to opt out of receiving important health information. Also, children have a right to an open future: parents do not have the right to access any genetic data that a biobank holds on their children. In this respect, the guidelines on genetic testing of minors are applicable. With regard to the duty of the researcher the question of whether researchers have a more stringent duty to return important health information when their research subjects are children is more difficult to answer. A researcher's primary duty is to perform useful research, a policy to return individual results must not hamper this task. The fact that vulnerable children are concerned, is an additional factor that should be considered when a policy of returning results is laid down for a specific collection or research project

The Storage and Use of Biological Tissue Samples from Minors for Research: A Focus Group Study

Genetic research on pediatric stored tissue samples raises specific ethical questions that differ from those raised when adults are the donors. To investigate opinions on this matter, we conducted 10 focus group discussions. Five focus groups were conducted with adult participants and 5 had teenage participants between 15 and 19 years old. The discussions were analyzed with NVIVO 8 (qualitative research software). We found the following recurrent categories: the requirement that research should not pose any burden on children and that it should benefit other children, the trust people had in the role of parents, the need for information and the growth towards autonomy. Both the adults and teenagers we interviewed thought that the inclusion of tissue samples from minors in research had ethical implications. A major concern was that nontherapeutic research would pose no extra burden on children, which would assume the use of nonintrusive methods of gathering samples and the use of samples that were gathered in a diagnostic context. Participants, however, also understood the necessity of such research. The overall impression was that parents would be the best persons to make decisions on behalf of a small child and that the same parents would engage their children in the decision-making when they grew older. People thought that there was a duty to recontact minors when they reached the age of competence but on a best-effort basis. Copyright (C) 2010 S. Karger AG, Base

Genetic research on stored tissue samples from minors: a systematic review of the ethical literature

The potential benefits of biobank research are well known. Also, the ethical implications of genetic research on stored tissue samples are well discussed in existing literature. The inclusion of tissue samples from minors may have significant scientific value. However, this inclusion raises specific ethical questions. We have performed a systematic search of the literature and found 21 theoretical and empirical articles dealing with the issue. After review, we distilled five clusters of themes: consent, risks, benefits, return of results, and ownership. We have described the different components of these themes, as they occurred in the literature and have provided a discourse on the topic