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Progress with the Human Variome Project, a collaborative global initiative that seeks to improve health by bringing together data on human genetic variation and its impact on human health (see previous news) have been published in the journal Science. Specifically, the project seeks to collate and curate existing and emerging data on all specific genetic variations known to affect human health (including rare genetic disorders and forms of common disease), and make it available for clinicians and researchers, facilitating the development and practice of evidence-based genetic medicine. This aim is very much in keeping with the practice of public health genomics, which incorporates knowledge integration across different disciplines as a key process to support the evaluation of evidence to support improvements in population health.
16 November 2008
Two new papers in the journal Nature have reported complete human diploid genome sequences, both male, from anonymous individuals of African and Asian ancestry. The African genome is that of a man from the Yoruba ethnic group in Nigeria, West Africa, and the Asian that of a man of Han Chinese descent. The original (haploid) human genome sequence was produced from a composite sample of DNA from several anonymous donors and completed in 2003. The first genome sequences from individuals were released in 2007, those of scientists Jim Watson (see previous news) and Craig Venter (see previous news), both of European descent. The Beijing Genomics Institute (BGI) in China announced completion of the first complete diploid genome sequence of a Chinese individual shortly afterwards (see previous news), but it has only now been published. The first individual female genome sequence has been hailed rather for its significance as the first genome from a cancer patient (see previous news).
14 November 2008
The low success rate of in vitro fertilisation (IVF) – just over 28% for women under 35 and lower for older women in the UK (see HFEA figures) – is partly attributable to the failure of aneuploid embryos (those with an abnormal number of chromosomes) to implant properly. Most such embryos would be non-viable in any case, and even the least severe forms of aneuploidy have significant clinical effects; for example, Down Syndrome, Edwards Syndrome and Patau Syndrome. In order to increase the chances of establishing a successful pregnancy, pre-implantation genetic screening (PGS) can be used to identify and select chromosomally normal embryos for implantation. This is currently done using fluorescent in situ hybridisation (FISH); however, this technique is only applied to find aneuploidies in up to eight specific chromosomes that are known to malfunction most frequently. In addition, the benefits of using this method for PGS have not been clearly established. The British Fertility Society in its recent guidelines recommended that PGS (using FISH) only be offered within the context of randomised trials, until further evidence of its effectiveness is gathered (see previous news).
An alternative technique for PGS is the use of comparative genomic hybridisation (CGH) (see previous news). CGH allows regions on every chromosome to be analysed for aneuploidies compared with current techniques, which are restricted to specific chromosomal defects. A number of studies have indicated that this technique may increase the success rate of IVF and the results of the first clinical study of this technique were presented at the annual meeting of the American Society of Reproductive Medicine. The study carried out by scientists at the University of Oxford and the Colorado Centre for Reproductive Medicine in the US has shown that CGH may be a better approach for pre-implantation genetic screening (reported by BBC news). The clinical trials were undertaken on 23 women with an average age of 37, in order to assess the effectiveness of CGH; chromosome screens were obtained for 91% of embryos tested and 70% percent of the cycles that went to embryo transfer resulted in clinical pregnancy (see press release). The results of this study suggest that the rate of implantation following CGH is dramatically greater than that achieved using other screening methods (BBC news). Dr. Dagan Wells from the University of Oxford is currently applying for a licence for its use in the UK. Although work on CGH has been on-going for a number of years, it has not been widely adopted as it is requires expertise, is labour intensive and takes several days. However, technological advances are making it a more amenable method of screening and if conjugated with microarray platforms (referred to as array CGH) it can allow high-throughput processing of multiple samples simultaneously.
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10 November 2008Human cancer cells typically exhibit numerous genetic aberrations, ranging from point mutations through to complete chromosome duplications. Whilst standard genome-wide association studies provide important insights into an individual’s genetic predisposition to cancer, they focus on inherited genetic variation; they do not address the new or ‘acquired’ genetic changes that contribute to cancer developing in specific cells at a specific time. However, since cancerous cells are genetically distinct from other, healthy cells in the same person, these genetic triggers can be assessed by comparing the cancer genome from a patient individual with the inherited genome of that individual.
8 November 2008
A new US research programme is attempting to determine links between specific genetic variants and different types of epilepsy, which causes recurrent seizures (fits). Some forms of epilepsy can affect multiple family members, suggesting a genetic basis for the condition in such cases. The Epilepsy Phenome/Genome Project (EPGP) is a five-year study that will bring together researchers from the National Institutes of Neurological Disorders and Stroke with clinicians and affected families from centres across the US (see Medical News Today article).
Epilepsy is not always easy to diagnose; there are various possible underlying causes including brain damage or infection, but the majority of cases have no known cause. It is hoped that the study, now recruiting a projected 3750 epilepsy patients and 3000 controls, might ultimately lead to improvements in diagnostic and therapeutic capability for the condition by identifying genes that influence both epilepsy and responses of affected individuals to anti-epileptic medicines.
7 November 2008
The US President's Council of Advisors on Science and Technology (PCAST) has released a report on personalised medicine containing recommendations on the governmental and private sector action needed in order to realise the benefits of personalised healthcare. The report, Priorities for Personalised Medicine is from a study on personalised healthcare that began in January 2007, in order to assess eight major policy areas including: technology/tools, regulation, reimbursement, information technology, intellectual property, privacy, education and economics. Although personalised healthcare can encompass a wide range of technologies such as imaging technologies as well as genomic diagnostics and therapeutics, it was decided to focus the report and its recommendations in three main areas (technology/tools, regulation and reimbursement) in relation to genomic-based molecular diagnostics, as these were felt to be the most pressing area for policy action.
The report explains some of the barriers preventing widespread adoption of personalised medicine such as ambiguous regulation, lack of translational research and limited coverage by health insurers, as well as potential mechanisms to overcome them. Its recommendations include calling on the US federal government to develop a strategic long-term plan that coordinates public and private sector efforts to advance research and development relevant to personalised medicine, and in particular the US Department of Health and Human Services (HHS) to establish a personalised medicine coordinating office. It also calls for a more transparent, iterative and systematic approach to regulation by the US Food and Drug Administration (FDA).
4 November 2008A team from the Gynaecological Cancer Research Centre at the UCL Institute for Women’s Health in London has launched a new project to identify individuals at increased genetic risk of developing forms of cancer. The Genetic Cancer Prediction through Population Screening (GCaPPS) pilot project has begun from a branch of the high street chemist Boots in Mill Hill, London; it is aiming to recruit volunteers from the local Ashkenazi Jewish population to be tested for genetic predisposition towards specific cancers.
1 November 2008
The World Medical Association has recently announced its 2008 revision of the Declaration of Helsinki: Ethical Principles for Medical Research Involving Human Subjects. The text is the result of the sixth comprehensive review of the Declaration, which was adopted by the WMA General Assembly in Helsinki, Finland in June 1964 and amended in 1975 (Tokyo), 1983 (Venice), 1989 (Hong Kong), 1996 (South Africa) and 2000 (Edinburgh). Notes of clarification to two specific paragraphs were added in 2002 and 2004.
30 October 2008
A new genetic testing methodology for pre-implantation genetic diagnosis (PGD) has been developed by scientists at the Bridge Centre in London (see the Times and the BBC news articles). According to media reports, this new methodology known as karyomapping has been hailed as a breakthrough technique which has the potential to test embryos produced via in vitro fertilisation (IVF) for almost any known genetic disorder. Currently, embryos that are produced by IVF can be screened for some chromosomal defects such as aneuploidies (known as pre-implantation genetic screening). If there is a known family history of a specific genetic disease such as cystic fibrosis, it is possible to perform prenatal genetic diagnosis (PGD) to select embryos without the condition for implantation, subject to the granting of a licence by the Human Fertilisation and Embryology Authority (HFEA). Such licences are granted on a case-by-case basis, although decisions in principle to permit licensing for specific conditions are sometimes taken; for example, adult onset hereditary forms of cancer (see previous news).
According to the news reports, the advantage of this methodology is that it can be used to screen a far wider range of genetic conditions as well as multiple genetic traits, and produces results in a shorter time period (BBC news). The technique involves the analysis of single nucleotide polymorphisms (SNPs) in DNA from parents and embryos to produce a ‘karyomap’ showing which parts of the embryo’s chromosomes have been inherited from which parent. In other words, it allows the origin of specific chromosomal segments to be identified and consequently also allows tracing of chromosomal segments that might be associated with a particular disease or phenotype. Thus far, the methodology used in producing karyomaps sounds remarkably similar to pre-implantation genetic haplotyping (PGH), which is used to identify haplotypes associated with familial disease regions (see previous news). However, a karyomap reportedly allows the identification of multiple genetic variations and aneuploidies, in addition to single gene defects.
24 October 2008The UK Human Fertilisation and Embryology Bill had its long awaited report and third reading in the House of Commons on 22 October 2008 (see BBC news). Although MPs from all parties were given a free vote on the amendments, there was general frustration at the lack of time devoted to the Bill (less than four hours) and the way in which amendments had been timetabled, which effectively prevented substantive debate on clauses relating to abortion, or the need for a father.