Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes.

Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based solely upon the nature of the substituting amino acid: a lysine at TWIST2 residue 75 resulted in AMS, whereas a glutamine or alanine yielded BSS. TWIST2 encodes a basic helix-loop-helix transcription factor that regulates the development of mesenchymal tissues. All identified mutations fell in the basic domain of TWIST2 and altered the DNA-binding pattern of Flag-TWIST2 in HeLa cells. Comparison of wild-type and mutant TWIST2 expressed in zebrafish identified abnormal developmental phenotypes and widespread transcriptome changes. Our results suggest that autosomal-dominant TWIST2 mutations cause AMS or BSS by inducing protean effects on the transcription factor's DNA binding.

Ablepharon macrostomia syndrome: A distinct genetic entity clinically related to the group of FRAS-FREM complex disorders.

Ablepharon macrostomia syndrome (AMS; OMIM 200110) is an extremely rare congenital malformation syndrome. It overlaps clinically with Fraser syndrome (FS; OMIM 219000), which is known to be caused by mutations in either FRAS1, FREM2, or GRIP1, encoding components of a protein complex that plays a role in epidermal-dermal interactions during morphogenetic processes. We explored the hypothesis that AMS might be either allelic to FS or caused by mutations in other genes encoding known FRAS1 interacting partners. No mutation in either of these genes was found in a cohort of 11 patients with AMS from 10 unrelated families. These findings demonstrate that AMS is genetically distinct from FS. It is proposed that it constitutes a separate entity within the group of FRAS-FREM complex disorders.

A connective tissue disorder caused by mutations of the lysyl hydroxylase 3 gene.

Lysyl hydroxylase 3 (LH3, encoded by PLOD3) is a multifunctional enzyme capable of catalyzing hydroxylation of lysyl residues and O-glycosylation of hydroxylysyl residues producing either monosaccharide (Gal) or disaccharide (Glc-Gal) derivatives, reactions that form part of the many posttranslational modifications required during collagen biosynthesis. Animal studies have confirmed the importance of LH3, particularly in biosynthesis of the highly glycosylated type IV and VI collagens, but to date, the functional significance in vivo of this enzyme in man is predominantly unknown. We report here a human disorder of LH3 presenting as a compound heterozygote with recessive inheritance. One mutation dramatically reduced the sugar-transfer activity of LH3, whereas another abrogated lysyl hydroxylase activity; these changes were accompanied by reduced LH3 protein levels in cells. The disorder has a unique phenotype causing severe morbidity as a result of features that overlap with a number of known collagen disorders.

Mutations in BMP4 cause eye, brain, and digit developmental anomalies: overlap between the BMP4 and hedgehog signaling pathways.

Developmental ocular malformations, including anophthalmia-microphthalmia (AM), are heterogeneous disorders with frequent sporadic or non-Mendelian inheritance. Recurrent interstitial deletions of 14q22-q23 have been associated with AM, sometimes with poly/syndactyly and hypopituitarism. We identify two further cases of AM (one with associated pituitary anomalies) with a 14q22-q23 deletion. Using a positional candidate gene approach, we analyzed the BMP4 (Bone Morphogenetic Protein-4) gene and identified a frameshift mutation (c.226del2, p.S76fs104X) that segregated with AM, retinal dystrophy, myopia, brain anomalies, and polydactyly in a family and a nonconservative missense mutation (c.278A-->G, p.E93G) in a highly conserved base in another family. MR imaging and tractography in the c.226del2 proband revealed a primary brain developmental disorder affecting thalamostriatal and callosal pathways, also present in the affected grandmother. Using in situ hybridization in human embryos, we demonstrate expression of BMP4 in optic vesicle, developing retina and lens, pituitary region, and digits strongly supporting BMP4 as a causative gene for AM, pituitary, and poly/syndactyly. Because BMP4 interacts with HH signaling genes in animals, we evaluated gene expression in human embryos and demonstrate cotemporal and cospatial expression of BMP4 and HH signaling genes. We also identified four cases, some of whom had retinal dystrophy, with "low-penetrant" mutations in both BMP4 and HH signaling genes: SHH (Sonic Hedgehog) or PTCH1 (Patched). We propose that BMP4 is a major gene for AM and/or retinal dystrophy and brain anomalies and may be a candidate gene for myopia and poly/syndactyly. Our finding of low-penetrant variants in BMP4 and HH signaling partners is suggestive of an interaction between the two pathways in humans.

Preventing the aortic complications of Marfan syndrome: a case-example of translational genomic medicine.

The translational path from pharmacological insight to effective therapy can be a long one. We aim to describe the management of Marfan syndrome as a case-example of how pharmacological and genomic insights can contribute to improved therapy. We undertook a literature search for studies of Marfan syndrome, to identify milestones in description, understanding and therapy of the syndrome. From the studies retrieved we then weaved an evidence-based description of progress. Marfan syndrome shows considerable heterogeneity in clinical presentation. It relies on defined clinical criteria with confirmation based on FBN1 mutation testing. Surgical advances have prolonged life in Marfan syndrome. First-line prophylaxis of complications with ß-adrenoceptor blockers became established on the basis that reduction of aortic pressure and heart rate would help. Over-activity of proteinases, first suggested in 1980, has since been confirmed by evidence of over-expression of matrix metalloproteinases (MMP), notably MMP-2 and MMP-9. The search for MMP inhibitors led to the evaluation of doxycycline, and both animal studies and small trials, provided early evidence that this widely used antimicrobial agent was useful. Identification of the importance of TGF-ß led to evaluation of angiotensin II type I receptor (AT(1) R) blockers with highly promising results. Combination prophylactic therapy would appear rational. Pharmacological and genomic research has provided good evidence that therapy with losartan and doxycycline would prevent the aortic complications of Marfan syndrome. If on-going well designed trials confirm their efficacy, the outlook for Marfan syndrome patients would be improved considerably.

The Pharmacogenetic Rescue of Side-Lined Anticancer Drugs to the Front-Line: Gefitinib as a Case Example.

OBJECTIVE: To illustrate the increasing importance of pharmacogenetics in drug development and clinical practice through a critical analysis of the validation and licensing of gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, as a treatment for non-small cell lung cancer (NSCLC). DATA SOURCES: Journal articles and the "grey" literature were identified through a systematic search of MEDLINE (to June 2010) and the Web sites of the major drug regulators. References identified through the reference lists of major published reviews of gefitinib and Erb receptors, including EGFR, were also reviewed. STUDY SELECTION AND DATA EXTRACTION: A broad appraisal of the titles and abstracts of articles on gefitinib and tyrosine kinase inhibitors in lung cancer was undertaken to identify pertinent concepts and relevant publications for further analysis. Articles deemed particularly relevant were retrieved for detailed appraisal. Dossiers on the licensing of gefitinib from the Food and Drug Administration Web site and major published reviews were retrieved. Relevant pharmacogenetic issues were identified and the clinical studies addressing these were evaluated. DATA SYNTHESIS: Initial promising trial data for gefitinib in NSCLC led to its conditional marketing approval. When the drug's efficacy was not confirmed in a pivotal Phase 3 trial, its prescribing was restricted. Subsequent discovery of activating mutations in the tyrosine kinase domain of EGFR led to further retrospective and prospective evaluation of the drug in patients with those mutations. The new evidence was sufficiently robust to persuade the drug regulators to license the drug as first-line treatment for patients with locally advanced or metastatic NSCLC who test positive for those mutations. CONCLUSIONS: Pharmacogenetic evidence has played a key role in rescuing gefitinib for front-line treatment of NSCLC. This case-example portends what will be increasingly likely scenarios in the regulation and clinical validation of targeted drug therapies.

Pharmacogenetics of CYP2C19: functional and clinical implications of a new variant CYP2C19*17.

AIMS: Cytochrome P450 2C19 metabolizes many important drugs. In 2006, a variant allele (CYP2C19*17) associated with increased activity was discovered, but its likely clinical significance is controversial. Investigators disagree about the phenotype to be assigned to the two CYP2C19*17 genotypes. The aim of this study was to provide a critical summary, helpful to prescribers. METHODS: We searched MEDLINE for papers on the allele from 2006 and then undertook historical searches through the reference lists of papers retrieved. The relevant information was critically assessed and summarized. RESULTS: CYP2C19*17 was associated with increased enzymic activity. Substrates studied were omeprazole, pantoprazole, escitalopram, sertraline, voriconazole, tamoxifen and clopidogrel. Most studies used pharmacokinetic variables as outcome measure. For clopidogrel, activated by CYP2C19, pharmacodynamic consequences focused on platelet aggregation. While for most pharmacokinetic parameters of the substrates studied the average value was altered, the range of values showed mostly complete overlap for CYP2C19*1/*17 heterozygotes and wild-type homozygotes. Even for CYP2C19*17 homozygotes, the absolute effect was modest compared with the effect of previously identified loss-of-function alleles. In Helicobacter pylori eradication CYP2C19*2 carriage was associated with an altered eradication rate (odds ratio 4.20, 95% confidence interval 1.23, 16.44) relative to the wild-type, but CYP2C19*17 homozygosity was not. Prevalence of the variant allele was typically <5% in Asians and about four times higher in White and African populations. CONCLUSIONS: Assignment of CYP2C19*17 homozygotes as extensive metabolizers rather than ultrarapid metabolizers is adequate. CYP2C19*17 genotyping is unlikely to have clinical utility except for drugs with very narrow therapeutic indices.

Integrating pharmacogenetics and therapeutic drug monitoring: optimal dosing of imatinib as a case-example.

PURPOSE: To illustrate the interface of pharmacogenetics and therapeutic drug monitoring and to estimate target blood level for imatinib in the treatment of chronic myelogenous leukemia METHODS: A literature review to provide the evidence and necessary data to support the case for the interface, and quantitative analysis of the data to estimate the target blood level for imatinib using receiver operating curve (ROC; signal detection theory) analysis. RESULTS AND DISCUSSION: One study estimated the optimum target level of imatinib in chronic myelogenous leukaemia as 1002 ng/mL (1.70 microM) through ROC analysis. Using individual-patient level data reported in another study and the same methodology, we estimated the target level as 0.95 microM. This is consistent with the results of other observational studies where dose-response was not the primary research objective. The available evidence suggests considerable inter-individual variability in dose-blood level response. In addition to the pharmacogenetics of metabolic enzymes and transporters, genetic mutations in genes participating in the signalling pathways may also account for the wide inter-individual variability in dose-blood level and dose-clinical response relationships. CONCLUSION: A single-dose regimen for all pharmacogenetically eligible patients is not the optimum strategy for prescribing imatinib to patients with chronic myelogenous leukaemia. We suggest that therapeutic drug monitoring aimed at ensuring a trough target level of 1 microM would reduce the incidence of pseudo-resistance and hence personalize treatment and optimise response to imatinib. Persistent resistance can then be probed further for other causes.

A toolkit for incorporating genetics into mainstream medical services: Learning from service development pilots in England.

BACKGROUND: As advances in genetics are becoming increasingly relevant to mainstream healthcare, a major challenge is to ensure that these are integrated appropriately into mainstream medical services. In 2003, the Department of Health for England announced the availability of start-up funding for ten 'Mainstreaming Genetics' pilot services to develop models to achieve this. METHODS: Multiple methods were used to explore the pilots' experiences of incorporating genetics which might inform the development of new services in the future. A workshop with project staff, an email questionnaire, interviews and a thematic analysis of pilot final reports were carried out. RESULTS: Seven themes relating to the integration of genetics into mainstream medical services were identified: planning services to incorporate genetics; the involvement of genetics departments; the establishment of roles incorporating genetic activities; identifying and involving stakeholders; the challenges of working across specialty boundaries; working with multiple healthcare organisations; and the importance of cultural awareness of genetic conditions. Pilots found that the planning phase often included the need to raise awareness of genetic conditions and services and that early consideration of organisational issues such as clinic location was essential. The formal involvement of genetics departments was crucial to success; benefits included provision of clinical and educational support for staff in new roles. Recruitment and retention for new roles outside usual career pathways sometimes proved difficult. Differences in specialties' working practices and working with multiple healthcare organisations also brought challenges such as the 'genetic approach' of working with families, incompatible record systems and different approaches to health professionals' autonomous practice. 'Practice points' have been collated into a Toolkit which includes resources from the pilots, including job descriptions and clinical tools. These can be customised for reuse by other services. CONCLUSIONS: Healthcare services need to translate advances in genetics into benefits for patients. Consideration of the issues presented here when incorporating genetics into mainstream medical services will help ensure that new service developments build on the body of experience gained by the pilots, to provide high quality services for patients with or at risk of genetic conditions.

Genetics in family health care: putting it into action.

This article builds on a previous article by suggesting practical ways in which genetics can be integrated into existing family health care practice. Some key skills such as collecting family history information, identifying clinical pointers suggestive of a genetic condition and knowing how to refer individuals for genetic counselling are discussed in detail. When talking about genetics, it is important to use the right words and be aware of the emotional issues that taking a family history may bring to light. Family health care practitioners are well placed to provide this support to individuals and families.

Genetics: what's it got to do with family health care?

Genetics is an important contributory factor in many medical conditions. Having an understanding of the genetic basis of diseases can therefore be helpful in identifying and supporting people who have, or are at risk of having, a genetic condition. Most of the current practical applications relate to conditions which are known to have a definite mode of inheritance (for instance cystic fibrosis or familial hypercholesterolaemia) or which are due to chromosomal anomalies (such as Down syndrome). Current research projects are attempting to identify and understand the genetic factors associated with common diseases (such as diabetes and Crohn's disease) but it will be some time before these are likely to be useful clinically. Key skills in the delivery of a holistic family practice service include being able to collect a genetic family history, identifying people at risk and knowing how to refer to specialist services.

The development of core learning outcomes relevant to clinical practice: identifying priority areas for genetics education for non-genetics specialist registrars.

Advances in medical genetics are increasingly impacting on clinical practice outside specialist genetic services. It is widely acknowledged that physicians will need to use genetics knowledge and skills in order to incorporate these advances into patient care. In order to determine priority areas for genetics education for non-genetics specialist registrars, an educational needs assessment was undertaken. Consultants from cardiology, dermatology, neurology and genetics identified genetics knowledge, skills and attitudes required by non-genetics specialty trainees. From these, and informed by trainees' views of genetic education, six genetics learning outcomes that non-genetics medical specialty trainees should attain by the end of their training have been identified, each linked to core knowledge, skills and attitudes. These core concepts can be taught with reference to specialty-specific conditions to highlight their relevance to clinical practice. The results of this study are informing the genetic component of postgraduate medical training curricula.

Family communication between children and their parents about inherited genetic conditions: a meta-synthesis of the research.

In families affected by an inherited genetic condition, parents face a difficult task of having to communicate genetic risk information to their children. A systematic review of all major health and medical research databases was undertaken using current guidelines to identify original relevant research papers from 1980 to 2007, which explore the issues surrounding parents and their children's communication about inherited genetic risk. A total of 9698 abstracts were found of which 158 research papers were reviewed as potentially relevant. A final 17 papers were identified which met predefined inclusion and exclusion criteria. Using a meta-ethnographic approach, all identified studies' findings were analysed as primary data sources by three researchers, who independently identified the key concepts. A high level of congruence emerged between researchers, and agreed concepts were used to examine similarities and differences between papers. The findings informed the development of a narrative framework exploring the issues that related to parents' explanations of inherited genetic risk to their children, the reasons for sharing information, children's understanding of parents' explanations, the emotions evoked for family members and the support and guidance received from health professionals. Providing information, checking understanding, and explaining and managing the emotional feelings that arise were integral to supporting children's coping with genetic risk information. However, many parents struggled with one or more of these components and required more support specific to the child's developmental stage, and family members' transition of readjustment to the impact of the genetic condition.

How can genetic tests be evaluated for clinical use? Experience of the UK Genetic Testing Network.

The UK Department of Health supported the establishment of the UK Genetic Testing Network (UKGTN) in 2002. The UKGTN is a collaborative network of NHS molecular genetic laboratories that offer tests for human single gene germ-line disorders. Its objective is to provide high quality and equitable services for patients and their families who require genetic advice, diagnosis and management. The UKGTN has developed a 'Gene Dossier' process to evaluate genetic tests and recommend which tests will be provided by the National Health Service. This paper describes the UKGTN organisation and the 'Gene Dossier' process. A brief review of the UKGTN genetic test evaluation experience is presented.

Competences, education and support for new roles in cancer genetics services: outcomes from the cancer genetics pilot projects.

In 2004 the Department of Health in collaboration with Macmillan Cancer Support set up service development projects to pilot the integration of genetics in mainstream medicine in the area of cancer genetics.In developing these services, new roles and responsibilities were devised that required supporting programmes of education and training. The NHS National Genetics Education and Development Centre has worked with the projects to draw together their experience in these aspects. New roles include the Cancer Family Nurse Specialist, in which a nurse working in a cancer setting was trained to identify and manage genetic or family history concerns, and the Genetic Risk Assessment Practitioner--a small team of practitioners working within a secondary care setting to deliver a standardised risk assessment pathway. Existing roles were also adapted for a different setting, in particular the use of genetic counsellors working in a community ethnic minority setting. These practitioners undertook a range of clinical activities that can be mapped directly to the 'UK National Workforce Competences for Genetics in Clinical Practice for Non-genetics Healthcare Staff' framework developed by Skills for Health and the NHS National Genetics Education and Development Centre (2007; draft competence framework). The main differences between the various roles were in the ordering of genetic tests and the provision of advice on invasive preventive options such as mastectomy. Those involved in service development also needed to develop competences in project management, business skills, audit and evaluation, working with users, general management (personnel, multi-agency work and marketing), educational supervision, IT, public and professional outreach, and research. Important resources to support the development of new roles and competences included pathways and guidelines, a formal statement of competences, a recognised syllabus, appropriate and timely courses, the availability of a mentor, supervision and opportunities to discuss cases, a formal assessment of learning and continuing support from specialist genetics services. This represents a current resource gap that will be of concern to cancer networks and a challenge to providers of educational resources and regional genetics services.

DISCERN-Genetics: quality criteria for information on genetic testing.

Information currently available to the public is inadequate to support those deciding to consent to a genetic test. As genetic knowledge continues to evolve, more people will be forced to consider the complex issues raised by genetic testing. We developed and tested criteria to guide the production and appraisal of information resources produced for the public on genetic testing. Lay people with and without experience of a genetic condition, and providers and producers of health information appraised and listed the criteria they used to rate the quality of a sample of information on cystic fibrosis, Down's syndrome, familial breast cancer, familial colon cancer, haemochromatosis, Huntington's disease, sickle cell disease, and thalassaemia. These genetic conditions represent different populations, disease pathways, and treatment decisions. The information medium could be written, electronic, CD, audio or video. The quality criteria were tested iteratively (using the weighted kappa statistic) for the level of agreement between users applying successive drafts of the criteria to different samples of information. The final set of criteria consisted of 19 questions plus an overall quality rating. Chance corrected agreement (weighted kappa) among the appraisers for the overall quality rating was 0.61 (0.60-0.62). The criteria cover the scope of the information resources, information on the condition, the test procedure and results, decision making, and the reliability of the information. The DISCERN-Genetics criteria will guide the production and appraisal of information produced for the public, and will facilitate the involvement of the public in decisions around genetic screening and testing.

Genetic information and testing in insurance and employment: technical, social and ethical issues.

The present paper examines the professional and scientific views on the social, ethical and legal issues that impact on genetic information and testing in insurance and employment in Europe. For this purpose, many aspects have been considered, such as the concerns of medical geneticists, of the insurers and employers, of the public, as well as the regulatory frameworks and unresolved issues. The method used was primarily the review of the technical, social, economical and ethical aspects of advances in genetics and the concerns of parties who are involved, that is, the insurers, the employers and the public. The existing guidelines and legislation on this topic were also reported. Then, the method was to examine the issues debated by these parties in Europe, as well as by 47 experts from 14 European countries invited to an international workshop organized by the European Society of Human Genetics Public and Professional Policy Committee in Manchester, UK, 25-27 February 2000. The result of this was that the most important issues raised by genetic information and testing in insurance and employment in Europe include a need for clear definitions of terms used in genetics, declaring the grounds on which genetic information is or is not used, and promoting confidence between the public and the insurance industry. There is currently very little use of genetic information in relation to employment, but the situation should be kept under review.

Developing a curriculum statement based on clinical practice: genetics in primary care.

BACKGROUND: Advances in medical genetics are increasingly being incorporated into clinical management outside specialist genetic services. This study was therefore undertaken to develop learning outcomes in genetics for general practice specialty training, using methods to ensure the knowledge, skills, and attitudes relevant to genetics in primary care were identified. AIM: To identify key knowledge, skills, and attitudes in genetics and to synthesise these into learning outcomes to assist training in genetics for primary care. DESIGN OF STUDY: Delphi survey and review by expert group. SETTING: Primary care practices and Regional Genetics Centre in the West Midlands region of the UK. METHOD: A modified Delphi survey involved GP trainers, programme directors, and geneticists (n = 60). The results, along with results from a survey of GP registrars, were reviewed by an expert group, which included GPs, geneticists, and educationalists. RESULTS: Core genetics topics for GPs were identified, prioritised, and developed into competency statements in the style of the curriculum structure of the Royal College of General Practitioners. CONCLUSION: The development of the GP curriculum statement Genetics in Primary Care was based on a study of educational needs, incorporating the views of practitioners (GP trainers, programme directors, and registrars) and specialists (clinical geneticists). This inclusive approach has enabled the identification of learning outcomes which directly reflect clinical practice.