Understanding and predicting a complex behaviour using n-of-1 methods : Photoprotection in xeroderma pigmentosum

Acknowledgements: We would like to thank Lesley Foster (research nurse) for all her work in setting up the n-of-1 study with patients; the XP national clinical team (Hiva Fassihi, Tanya Henshaw, Sally Turner, Isabel Garrood, Alan Lehmann) and members of the PPI panel (Cathy Coleman, Ben Fowler, Sandra Webb, Ros Tobin) for input into design of materials. Funding: This research is funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research (RP-PG- 1212-20009). The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR, NHS, or the Department of Health.Peer reviewedPostprin

The influence of perceived medical risks and psychosocial concerns on photoprotection behaviours among adults with xeroderma pigmentosum : a qualitative interview study in the UK

BACKGROUND: A high level of photoprotection is required by people with xeroderma pigmentosum (XP), a rare skin disease, to reduce skin cancer and other risks. However poor photoprotection is thought to be widespread. PURPOSE: This study examines the influences on photoprotection behaviours in adults with XP. DESIGN: Inductive qualitative study with semistructured interviews. Analysis employed a framework approach. SETTING: National sample recruited through a specialist XP centre in London. METHODS: Semistructured interviews at patients’ homes. All transcripts were coded and themes charted for each participant. Comparisons within and across cases identified common themes and differing motivations and approaches to photoprotection. Credibility of interpretations assessed through patient/carer input and clinic adherence scores. PARTICIPANTS: 25 adults (17 male, eight female) aged 16–63 years with diagnosed XP attending a specialist centre. 18 lived outside London. RESULTS: Awareness of risks of ultraviolet radiation (UVR) and photoprotection was high. However, photoprotection behaviours varied according to perceived necessity and concerns. Three behavioural responses were identified: (1) ‘dominated’ by planning and routines to achieve a high level of photoprotection with significant activity restrictions and psychosocial impacts. (2) ‘resistant’ to photoprotection with priority given to avoiding an illness identity and enjoying a normal life. (3) Photoprotection’ integrated’ with an individual’s life with little psychosocial impact. These responses were influenced by illness, personal and contextual factors including age, life stage and social support. Only the ‘integrated’ group achieved an equilibrium between perceived ‘necessity’ and ‘concerns’. CONLCUSIONS: The personal balance between perceived risks of UVR and social/psychological ‘concerns’ led to differing behavioural responses and contributes to an understanding of adaptation and normalisation in chronic illness. The study will also inform a series of individualised behavioural interventions to reduce measured UVR exposure among people with XP that are potentially applicable to other conditions with high risks of skin cancer

Identifying the psychosocial predictors of ultraviolet exposure to the face in patients with xeroderma pigmentosum:A study of the behavioural factors affecting clinical outcomes in this genetic disease

BACKGROUND: For patients with xeroderma pigmentosum (XP), the main means of preventing skin and eye cancers is extreme protection against ultraviolet radiation (UVR), particularly for the face. We have recently developed a methodology for objectively measuring photoprotection behaviour (‘UVR dose to facial skin’) and have found that the degree of photoprotection varies greatly between patients with XP. We have previously identified factors affecting photoprotection behaviour in XP using a subjective measure of photoprotection. Here, we have used this objective methodology to identify the factors which determine photoprotection behaviour in XP. METHODS: We studied 29 psychological, social, demographic and clinical variables in 36 patients with XP. We have previously objectively measured UVR protection (by measuring the dose of UVR reaching the skin of the face over a 3-week period) in these patients. Here, we use linear mixed-effects model analysis to identify the factors which lead to the differences in degree of photoprotection observed in these patients. RESULTS: Psychosocial factors accounted for as much of the interindividual variation in photoprotection behaviour (29%) as demographic and clinical factors (24%). Psychosocial factors significantly associated with worse UVR protection included: automaticity of the behaviours, and a group of beliefs and perceptions about XP and photoprotection known to associate with poor treatment adherence in other diseases. CONCLUSIONS: We have identified factors contributing to poor photoprotection in XP. Identifying these potentially reversible psychosocial features has enabled us to design an intervention to improve photoprotection in patients with XP, aiming to prevent skin and eye cancers in these patients

[Letter] A distinct genotype of XP complementation group A: surprisingly mild phenotype highly prevalent in Northern India/ Pakistan/ Afghanistan

No description supplie

Dramatic response of metastatic cutaneous angiosarcoma to an immune checkpoint inhibitor in a patient with xeroderma pigmentosum: whole-genome sequencing aids treatment decision in end-stage disease.

"Mutational signatures" are patterns of mutations that report DNA damage and subsequent repair processes that have occurred. Whole-genome sequencing (WGS) can provide additional information to standard diagnostic techniques and can identify therapeutic targets. A 32-yr-old male with xeroderma pigmentosum developed metastatic angiosarcoma that was unresponsive to three lines of conventional sarcoma therapies. WGS was performed on his primary cancer revealing a hypermutated tumor, including clonal ultraviolet radiation-induced mutational patterns (Signature 7) and subclonal signatures of mutated DNA polymerase epsilon (POLE) (Signature 10). These signatures are associated with response to immune checkpoint blockade. Immunohistochemistry confirmed high PD-L1 expression in metastatic deposits. The anti-PD-1 monoclonal antibody pembrolizumab was commenced off-label given the POLE mutation and high mutational load. After four cycles, there was a significant reduction in his disease with almost complete resolution of the metastatic deposits. This case highlights the importance of WGS in the analysis, interpretation, and treatment of cancers. We anticipate that as WGS becomes integral to the cancer diagnostic pathway, treatments will be stratified to the individual based on their unique genomic and/or transcriptomic profile, enhancing classical approaches of histologically driven treatment decisions

An investigation of the predictors of photoprotection and UVR dose to the face in patients with XP : a protocol using observational mixed methods

INTRODUCTION: Xeroderma pigmentosum (XP) is a rare genetic condition caused by defective nucleotide excision repair and characterised by skin cancer, ocular and neurological involvement. Stringent ultraviolet protection is the only way to prevent skin cancer. Despite the risks, some patients' photoprotection is poor, with a potentially devastating impact on their prognosis. The aim of this research is to identify disease-specific and psychosocial predictors of photoprotection behaviour and ultraviolet radiation (UVR) dose to the face. METHODS AND ANALYSIS: Mixed methods research based on 45 UK patients will involve qualitative interviews to identify individuals' experience of XP and the influences on their photoprotection behaviours and a cross-sectional quantitative survey to assess biopsychosocial correlates of these behaviours at baseline. This will be followed by objective measurement of UVR exposure for 21 days by wrist-worn dosimeter and daily recording of photoprotection behaviours and psychological variables for up to 50 days in the summer months. This novel methodology will enable UVR dose reaching the face to be calculated and analysed as a clinically relevant endpoint. A range of qualitative and quantitative analytical approaches will be used, reflecting the mixed methods (eg, cross-sectional qualitative interviews, n-of-1 studies). Framework analysis will be used to analyse the qualitative interviews; mixed-effects longitudinal models will be used to examine the association of clinical and psychosocial factors with the average daily UVR dose; dynamic logistic regression models will be used to investigate participant-specific psychosocial factors associated with photoprotection behaviours. ETHICS AND DISSEMINATION: This research has been approved by Camden and King's Cross Research Ethics Committee 15/LO/1395. The findings will be published in peer-reviewed journals and presented at national and international scientific conferences

100,000 Genomes Pilot on Rare-Disease Diagnosis in Health Care — Preliminary Report

BACKGROUND: The U.K. 100,000 Genomes Project is in the process of investigating the role of genome sequencing in patients with undiagnosed rare diseases after usual care and the alignment of this research with health care implementation in the U.K. National Health Service. Other parts of this project focus on patients with cancer and infection. METHODS: We conducted a pilot study involving 4660 participants from 2183 families, among whom 161 disorders covering a broad spectrum of rare diseases were present. We collected data on clinical features with the use of Human Phenotype Ontology terms, undertook genome sequencing, applied automated variant prioritization on the basis of applied virtual gene panels and phenotypes, and identified novel pathogenic variants through research analysis. RESULTS: Diagnostic yields varied among family structures and were highest in family trios (both parents and a proband) and families with larger pedigrees. Diagnostic yields were much higher for disorders likely to have a monogenic cause (35%) than for disorders likely to have a complex cause (11%). Diagnostic yields for intellectual disability, hearing disorders, and vision disorders ranged from 40 to 55%. We made genetic diagnoses in 25% of the probands. A total of 14% of the diagnoses were made by means of the combination of research and automated approaches, which was critical for cases in which we found etiologic noncoding, structural, and mitochondrial genome variants and coding variants poorly covered by exome sequencing. Cohortwide burden testing across 57,000 genomes enabled the discovery of three new disease genes and 19 new associations. Of the genetic diagnoses that we made, 25% had immediate ramifications for clinical decision making for the patients or their relatives. CONCLUSIONS: Our pilot study of genome sequencing in a national health care system showed an increase in diagnostic yield across a range of rare diseases. (Funded by the National Institute for Health Research and others.)

Germline selection shapes human mitochondrial DNA diversity.

Approximately 2.4% of the human mitochondrial DNA (mtDNA) genome exhibits common homoplasmic genetic variation. We analyzed 12,975 whole-genome sequences to show that 45.1% of individuals from 1526 mother-offspring pairs harbor a mixed population of mtDNA (heteroplasmy), but the propensity for maternal transmission differs across the mitochondrial genome. Over one generation, we observed selection both for and against variants in specific genomic regions; known variants were more likely to be transmitted than previously unknown variants. However, new heteroplasmies were more likely to match the nuclear genetic ancestry as opposed to the ancestry of the mitochondrial genome on which the mutations occurred, validating our findings in 40,325 individuals. Thus, human mtDNA at the population level is shaped by selective forces within the female germ line under nuclear genetic control, which ensures consistency between the two independent genetic lineages.NIHR, Wellcome Trust, MRC, Genomics Englan