Rhian Morgan

Increased frequency of the haemochromatosis Cys282Tyr mutation in sporadic porphyria cutanea tarda.

BACKGROUND Sporadic porphyria cutanea tarda is a skin disease associated with hepatic siderosis. Depletion of iron stores by phlebotomy is curative. The role of haemochromatosis genes in determining susceptibility to this disorder is controversial. We have examined the frequency in sporadic porphyria cutanea tarda of mutations (Cys282Tyr, His63Asp) in a novel MHC class-I-like gene, one of which (Cys282Tyr) is believed to cause haemochromatosis. METHODS 41 patients with sporadic porphyria cutanea tarda, in whom the frequency of microsatellite alleles that define the ancestral haemochromatosis haplotype had previously been determined, and 101 healthy blood donors were studied for the presence of the Cys282Tyr and His63Asp mutations. We used restriction-enzyme digestion of PCR-amplified genomic DNA. FINDINGS The Cys282Tyr mutation occurred in 18 (44%) of patients compared with 11 (11%) of controls (relative risk 6.2, 95% CI 2.6-14.5, p = 0.00003). Seven (17%) patients, aged 48-79 years, were homozygotes. In 12 patients, the Cys282Tyr mutation was associated with markers of the HLA-A3-containing ancestral haemochromatosis haplotype. Ages at presentation were the same for those with or without the Cys282Tyr mutation. There was no difference in the frequency of the His63Asp mutation. INTERPRETATION Inheritance of one or more haemochromatosis genes is an important susceptibility factor for sporadic porphyria cutanea tarda. Some homozygotes for the Cys282Tyr mutation present late in life with porphyria cutanea tarda, indicating that not all homozygotes present clinically with haemochromatosis. The relation between this genotype and disease needs further investigation.

Variegate Porphyria in Western Europe: Identification of PPOX Gene Mutations in 104 Families, Extent of Allelic Heterogeneity, and Absence of Correlation between Phenotype and Type of Mutation

Variegate porphyria (VP) is a low-penetrance, autosomal dominant disorder characterized clinically by skin lesions and acute neurovisceral attacks that occur separately or together. It results from partial deficiency of protoporphyrinogen oxidase encoded by the PPOX gene. VP is relatively common in South Africa, where most patients have inherited the same mutation in the PPOX gene from a common ancestor, but few families from elsewhere have been studied. Here we describe the molecular basis and clinical features of 108 unrelated patients from France and the United Kingdom. Mutations in the PPOX gene were identified by a combination of screening (denaturing gradient gel electrophoresis, heteroduplex analysis, or denaturing high-performance liquid chromatography) and direct automated sequencing of amplified genomic DNA. A total of 60 novel and 6 previously reported mutations (25 missense, 24 frameshift, 10 splice site, and 7 nonsense) were identified in 104 (96%) of these unrelated patients, together with 3 previously unrecognized single-nucleotide polymorphisms. VP is less heterogeneous than other acute porphyrias; 5 mutations were present in 28 (26%) of the families, whereas 47 mutations were restricted to 1 family; only 2 mutations were found in both countries. The pattern of clinical presentation was identical to that reported from South Africa and was not influenced by type of mutation. Our results define the molecular genetics of VP in western Europe, demonstrate its allelic heterogeneity outside South Africa, and show that genotype is not a significant determinant of mode of presentation.

Identification of sequences required for the import of human protoporphyrinogen oxidase to mitochondria.

Protoporphyrinogen oxidase (PPOX; EC 1.3.3.4), the penultimate enzyme of haem biosynthesis, is a nucleus-encoded flavoprotein strongly associated with the outer surface of the inner mitochondrial membrane. It is attached to this membrane by an unknown mechanism that appears not to involve a membrane-spanning domain. The pathway for its import to mitochondria and insertion into the inner membrane has not been established. We have fused human PPOXs containing N-terminal deletions, C-terminal deletions or missense mutations to yellow fluorescent protein (YFP) and have used these constructs to investigate the mitochondrial import of PPOX in human cells. We show that all the information required for efficient import is contained within the first 250 amino acid residues of human PPOX and that targeting to mitochondria is prevented by fusion of YFP to the N-terminus. Deletion of between 151 and 175 residues from the N-terminus is required to abolish import, whereas shorter deletions impair its efficiency. Fully efficient targeting appears to require both a major targeting signal, the whole or part of which is contained between residues 151 and 175, and which may be involved in anchoring to the inner mitochondrial membrane, together with interaction between this region and a sequence(s) within the first 150 residues. These features suggest that the mechanism for import of human PPOX to mitochondria differs from those identified for the translocation of nucleus-encoded, membrane-spanning, inner membrane proteins. In addition, a missense mutation outside this region (Val(335)-->Gly) prevented targeting to mitochondria and delayed the appearance of YFP fluorescence. This mutation appeared to prevent import by a direct effect on protein folding rather than by altering a sequence required for targeting. It may lead to sequestration of the PPOX-YFP construct in an unfolded conformation, followed by proteolytic degradation, possibly through enhanced binding to a cytosolic chaperone protein.

Storytellers as partners in developing a genetics education resource for health professionals

Summary Advances in genetics are bringing unprecedented opportunities for understanding health and disease, developing new therapies and changes in healthcare practice. Many nurses and midwives lack competence and confidence in integrating genetics into professional practice. One approach to enhance understanding of genetics is to simulate clinical exposure through storytelling. Stories are acknowledged as a powerful learning tool, being understandable and memorable, stimulating critical thinking, and linking theory to practice. Telling Stories, Understanding Real Life Genetics is a freely accessible website that sets peoples stories within an education framework. The links between the stories and professional practice are made explicit and additional features support learning and teaching. Care of the storytellers within an ethical framework is of paramount importance. Storytellers are viewed as partners in the project. The challenges encountered include preserving the authentic voice and dignity of the storyteller. Project team members have also experienced ‘professional shame’ when negative experiences have been recounted, and the stories have had an impact on the team. The experience of working with storytellers has been positive. The storytellers want to be heard so that others will benefit from their stories. They serve as a reminder of why this work is important.

Comparison of Transcription-Mediated Amplification and Growth-Based Methods for the Quantitation of Enterococcus Bacteria in Environmental Waters

ABSTRACT An assay based on transcription-mediated amplification (TMA) technology was used to quantitate Enterococcus fecal indicator bacteria in environmental water samples. The results generated by this and two growth-based methods relative to the 104 most-probable-number or CFU-per-100-ml threshold show that the three methods are in good qualitative agreement when tested against a range of water samples taken from different locations. The results demonstrate sensitive and rapid detection (approximately 4 h from sample collection to result) and quantitation of Enterococcus bacteria compared to the results with the growth-based methods.

An objective approach to evaluating an internet-delivered genetics education resource developed for nurses: using Google Analytics™ to monitor global visitor engagement

The rapid increase in gene-disease discoveries offers real promise of clinical applications for people and families affected by genetic conditions but for which health professionals are not prepared because of lack of training. The availability of clinically relevant education resources is critical to enabling nurses to develop the appropriate genetics-genomics knowledge and skills to provide optimum care for individuals and families. The Internet is a core resource to support teaching and learning in nurse education. Evaluating such resources is important to maximise the education experience, particularly for subjects traditionally perceived by nurses as being difficult. Telling Stories, Understanding Real Life Genetics is a web-based educational resource. It uses real accounts from individuals and professionals to promote understanding of the impact of genetics-genomics on the lives of people and their families. Google Analytics™ Web analytics service provides time series data for analysing web usage to optimise website effectiveness. We present data of visitor activity and behaviour from 123 countries over three years from 2009–2011 and consider how the application of the web analytics informs approaches to enhancing visibility of the website, provides an indicator of engagement with genetics-genomics both nationally and globally, and informs future expansion of the site as a global resource for health professional education. Telling Stories is an accessible, broad-reaching resource that is of global relevance for health professionals, attracting over 33,500 visitors between 2009–2011, with steadily increasing numbers of returning visitors. The United Kingdom, United States, Canada and the Netherlands are the largest site users. Returning visitors spend significantly more time on site and view more pages than new visitors. Most referring sites are education establishments. More needs to be done now to enhance the site’s accessibility for people of other languages and cultures.

Tailoring genetic/genomic services and information to the individual.

This article examines how to develop confidence and competence in tailoring genetic/genomic information for different patients. The focus is on the issues that nurses working in a multicultural society need to be aware of, and include taking into account peoples ethnicity, culture, religion and ethical perspectives, as well as their developmental stage.