Apr 30, 2009
Apr 29, 2009
Lo scorso febbraio per via di una conferenza stampa, è stata data la notizia di una nuova procedura che consente di diagnosticare tutti i tipi di malattie genetiche e cromosomiche a trasmissione materna senza toccare gli embrioni. La tecnica, chiamata “diagnosi pre-concepimento” e pubblicata sul numero di gennaio della rivista scientifica Prenatal Diagnosis, è stata messa a punto da un team italiano coordinato da Francesco Fiorentino, biologo molecolare e direttore del Laboratorio Genoma di Roma.
In Italia la legge 40 sulla fecondazione assistita è molto controversa e, fino ad oggi, ha vietato la diagnosi pre-impianto. La problematica etica riguarda la possibilità di selezionare gli embrioni con l’eliminazione di quelli malati. La diagnosi genetica pre-concepimento viene eseguita sull’ovocita e non sull’embrione. In particolare, la tecnica permette di studiare i gameti femminili prima della loro fertilizzazione in vitro con lo scopo di escludere quegli oociti il cui DNA risulta alterato alla diagnosi, ed evitare quindi a priori la possibilità di produrre embrioni con anomalie genetiche. In quest’ottica la diagnosi pre-concepimento consente di superare gli ostacoli etici. “Con questo metodo siamo riusciti ad ottenere una prima gravidanza in una donna laziale portatrice per la sindrome Charcot Marie Tooth. Reduce da gravidanze andate male e da viaggi all’estero, la donna è oggi al suo terzo mese e i dati ottenuto dalla villocentesi hanno confermato che il feto è sano”, ha dichiarato Francesco Fiorentino.
La procedura, che è stata finora effettuata in via sperimentale, è stata validata a livello internazionale ed è ora in fase di proposta per l’attuazione in ambito sanitario. Le patologie genetiche per le quali la diagnosi pre-impianto potrebbe trovare una valida applicazione comprendono quelle a trasmissione autosomica recessiva, come ad esempio la fibrosi cistica, la talassemia e la SMA, o quelle di origine materna, quali la distrofia muscolare di Duchenne-Becker e l’X-Fragile.
Secondo Francesco Fiorentino questa nuova tecnica ha le potenzialità di dare, in un futuro prossimo, una reale possibilità alle coppie italiane portatrici di queste patologie di avere figli sani, senza dover ricorrere a costosi viaggi all’estero per ottenere trattamenti vietati in Italia.
Intervista a Francesco Fiorentino su RadioRadicale
Apr 28, 2009
Apr 24, 2009
Apr 23, 2009
from 7th space interactive
Apr 22, 2009
Apr 21, 2009
Apr 20, 2009
Mark Henderson has a great piece in the Times exploring the impact of personal genomics on the practice of medicine.
The basic theme should be familiar to anyone who has been following the emergence of the personal genomics industry: doctors are currently almost completely unprepared for the onslaught of genetic information they are about to experience. Here's the situation: at present, genetic training focuses on Mendelian diseases - rare mutations in single genes, which usually have severe effects. People who inherit the Huntington's mutation, for example, will invariably develop the fatal brain disorder, while 80 per cent of women who have a mutated BRCA1 gene will contract breast cancer.
This focus is perfectly understandable. Doctors need to understand and recognise these disorders, even if they will see few cases. Until recently, too, Mendelian conditions were the only ones for which genetic roots had been properly established. A knowledge of these rare diseases, however, is not going to be much help when patients start to visit their GPs waving printouts from genome scans like the one I took.
The genome scans Henderson describes are analyses of hundreds of thousands of common genetic variants scattered throughout the genome, currently offered by companies such as 23andMe, deCODEme and Navigenics (Henderson had his own genome scan performed by deCODEme). Over the last three years around 400 of these common variants have been convincingly associated with almost 80 common diseases and complex traits - everything from eye colour to prostate cancer - but each variant typically has a very small effect on disease risk, usually increasing it by 10-70% above baseline risk. That means that the results of a modern genome scan are very different to the clear-cut diagnostic genetic tests that clinicians are most familiar with: instead of telling a patient that they will almost certainly contract a serious, rare disease, clinicians are faced with a series of fuzzy probabilities: a lifetime risk of type 2 diabetes of 27% compared to the population average of 22%, for example.
The task of sorting clinically relevant information from statistical noise is daunting even for experts - let alone for GPs, lacking any training in modern genomics, who might have a 10 or 15 minute consultation to reassure a bewildered patient. In such cases the temptation must be strong to simply shrug their shoulders, tell the patient that the whole lot is garbage, and get back to the business of treating patients with actual diseases.
Yet to do so would be a grave mistake. Even current genome scans can yield clinically valuable data regarding the risk of some diseases, such as Alzheimer's, or the risk of adverse reactions to drugs like warfarin. But it's also crucial to note that current genome scans represent just our first feeble steps into the world of predictive health genetics: in less than five years large-scale DNA sequencing will be cheap enough for whole-genome sequencing to become routine, and during that time our understanding of the genetic basis of common diseases will continue to grow exponentially. If individual doctors - and the medical establishment as a whole - fail to adapt quickly to the approaching genomic era then patients will miss out on the substantial benefits of genomic medicine.
The only possible solution is intensive clinician education: both incorporating genomic knowledge deeply into medical degrees, and offering continuing education to practising doctors. Of course it's hard to teach about a field that is developing so rapidly, and Henderson notes that course material will need to be broad and flexible:
Personal genomics is in its infancy, and with new discoveries emerging all the time, we cannot yet know the detail of what tomorrow's doctors will need to know. They do not need to learn about every variant that has been linked to a disease risk or drug response: that knowledge remains incomplete, and it can always be looked up. What they do require, however, is an appreciation of how genetic discoveries are likely to become integrated into medical practice, and basic skills to make the most of them. In other words, doctors won't need to memorise the fact that the T version of variant rs7903146 is associated with type 2 diabetes; but they will need to know the difference between a SNP and a CNV, or between a genome scan and a genome sequence. They will need to become familiar with the terminology and interpretation of probabilistic genetic risk estimates and with the use of available online resources.
There is genuine urgency here. Right now it is a simple fact that 23andMe explains the implications of a genome scan far more accurately than the vast majority of clinicians ever could, a fact that makes many of the lamentations of the medical establishment about the dangers of direct-to-consumer genomics (at least at the high end of the market, i.e. 23andMe and deCODEme) seem rather absurd. If clinicians want to re-establish their centrality in the era of genomic medicine they have a lot of catching up to do - and they need to do it fast.
Apr 19, 2009
Apr 18, 2009
Apr 17, 2009
In uno studio pubblicato su Nature Medicine un gruppo di ricercatori dell'università americana di Stanford ha identificato un gruppo di 18 proteine usate dalle cellule per comunicare tra di loro e che permettono di predire con un'accuratezza del 90 per cento se una persona svilupperà o meno la malattia.
Esiste una connessione fra i cambiamenti che si verificano nel cervello di chi soffre di Alzheimer e il modo in cui le cellule comunicano fra di loro. Per i ricercatori, guidati dal professor Tony Wyss-Coral, il test che coglie le modificazioni in queste proteine è in grado di determinare se la malattia si svilupperà nei successivi due-sei anni, in anticipo quindi rispetto alla comparsa dei sintomi più significativi.
I ricercatori hanno analizzato 259 campioni di sangue da diversi pazienti: alcuni colpiti dai primi sintomi della malattia, altri già a stadi conclamati e avanzati, altri ancora che non presentavano alcun sintomo. E, partendo da un gruppo di 120 proteine note per la loro attività di comunicazione fra le cellule, ne hanno individuate 18 chiave, specifiche, che sono espresse in concentrazioni diverse nelle persone malate di Alzheimer. Queste proteine sono anche implicate nella produzione di nuove cellule del sangue, nei processi immunitari e nella morte delle cellule al termine del loro ciclo naturale. L'ipotesi è che ci sia qualcosa di errato nell'informazione contenuta nel DNA e che porta alla produzione di determinate cellule del sangue che svolgono un ruolo importante nell'eliminare quei depositi che si accumulano nel cervello delle persone malate di Alzheimer. La diagnosi precoce rappresenta un'arma in più per combattere l'Alzheimer.
What is genetic testing? A type of medical test that identifies changes in the DNA. Tests can target gene mutations or variations of single nucleotides and can be used in diagnostic to find changes associated with inherited disorders or as a prevention to assess the risk in developing a certain disease. The results of the test can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder.
What are the types of genetic tests? Genetic testing can provide information about a person’s genes and chromosomes. Available types of testing include:
· Newborn screening – used just after birth to identify genetic disorders that can be treated early in life.
· Diagnostic testing – used to identify or rule out a specific genetic or chromosomal condition.
· Prevention testing – offered to individuals who have a family history of a genetic disorder and to people in certain ethnic groups with an increased risk of specific genetic conditions.
· Prenatal testing – used to detect changes in a foetus’s genes or chromosomes before birth. It is offered during pregnancy if there is an increased risk that the baby will have a genetic or chromosomal disorder.
· Preimplantation testing – preimplantation genetic diagnosis (PGD), used to detect genetic changes in embryos created using assisted reproductive techniques.
· Predictive and presymptomatic testing – used to detect gene mutations associated with disorders that appear later in life. Can be helpful to people with a family member with a genetic disorder, but who have no features of the disorder themselves at the time of testing. Predictive testing can identify mutations that increase a person’s risk of developing disorders with a genetic basis, such as certain types of cancer.
· Forensic testing – uses DNA sequences to identify an individual for legal purposes.
How is genetic testing done? Genetic tests are performed on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds a foetus during pregnancy), or other tissue. The sample is sent to a laboratory where technicians look for specific changes in chromosomes, DNA, or proteins, depending on the suspected disorder. The laboratory reports the test results in writing to a person’s doctor or genetic counsellor.
What do the results of genetic tests mean? The results of genetic tests are not always straightforward, therefore it is important for patients and their families to ask questions about the potential meaning of genetic test results both before and after the test is performed. When interpreting test results, healthcare professionals consider a person’s medical history, family history, and the type of genetic test that was done. It is important to note that a positive result of a predictive or presymptomatic genetic test usually cannot establish the exact risk of developing a disorder.
What is the cost of genetic testing, and how long does it take to get the results? It can range from under $200 to more than $2000 (US Dollars), depending on the nature and complexity of the test. From the date that a sample is taken, it may take a few weeks to a few months to receive the test results. The doctor or genetic counsellor who orders a particular test can provide specific information about the cost and time frame associated with that test.
Will health insurance cover the costs of genetic testing? In many cases, health insurance plans will cover the costs of genetic testing when it is recommended by a person’s doctor. Health insurance providers have different policies about which tests are covered. A person interested in submitting the costs of testing may wish to contact his or her insurance company beforehand to ask about coverage.
What are the benefits of genetic testing? Genetic testing has potential benefits whether the results are positive or negative for a gene mutation. Test results can provide a sense of relief from uncertainty and help people make informed decisions about managing their health care. A negative result can eliminate the need for unnecessary checkups and screening tests in some cases; a positive result can direct a person toward available prevention, monitoring, and treatment options.
What are the risks and limitations of genetic testing? The physical risks associated with most genetic tests are very small, particularly for those tests that require only a blood sample or buccal smear. Most of the risks associated with genetic testing involve the emotional, social, or financial consequences of the test results. Genetic testing can provide only limited information about an inherited condition. The test often can’t determine if a person will show symptoms of a disorder, how severe the symptoms will be, or whether the disorder will progress over time. Another limitation is the lack of treatment strategies for many genetic disorders once they are diagnosed. A genetics professional can explain in detail the benefits, risks, and limitations of a particular test.
What is genetic discrimination? There is no risk of genetic discrimination when people undergo genetic testing by their employer or insurance company due to the G.I.N.A.How does genetic testing in a research setting differ from clinical genetic testing? The main differences are the purpose of the test and who receives the results. The goals of research testing include finding unknown genes, learning how genes work, and advancing our understanding of genetic conditions. The results of these testing are usually not available to patients or their healthcare providers. Clinical testing is done to find out about an inherited disorder in an individual patient or family. People receive the results of their tests and can use them to make decisions about medical care or reproductive issues. Clinical and research testing must both involve a process of informed consent in which patients learn about the testing procedure, the risks and benefits of the test, and the potential consequences of testing.
Apr 16, 2009
We all know that the sun's rays are becoming more dangerous over the years and the increased incidence of skin cancer (or melanoma) is one proof. Now researchers writing in The Lancet, a prestigious medical journal, have discovered the world's most effective sunscreen. Short of staying indoors, this method of blocking the sun's rays works better than any SPF product yet invented. What is this great new product? Wear proper protective clothing.
Ah ah ah you say? Well, it turns out, there is a lot to learn about protective clothing, since more and more people are relying on it, and not all protective clothing is created equal. According to the authors, the best protection comes from tightly woven clothing combined with a good hat. The study looked at different clothing and found that a light cotton t-shirt (probably the most frequently worn protection) actually only provides the equivalent of around SPF 10. As importantly, the study found that a wet t-shirt affords less protection than dry, something that snorklers should take into account when protecting themselves from the sun. In general it appears, thickness, weight, color and porosity all matter - so if you are going to rely on clothing, make sure it's the right stuff.
For those (the vast majority of us) who somehow don't think a day at the beach is quite the same when covered head to toe, the authors have some other helpful hints:
- Apply the sunscreen over your entire body in a uniform manner and don't skimp. Barriers that are opaque, such as zinc oxide, work best
- Any sunscreen that is organically based should be applied at least 15 minutes before exposure
- Be sure to use sunscreens that are waterproof or water-resistant, and of course, the higher the SPF the better
Apr 15, 2009
The successful completion of the human genome project is a great scientific finding and will bring about a big hopes for eternal life. As far as eternal life is concerned, the secret recipe is not hidden in some mystic place in the world, but lies in human genes. The reason is that for any given individual, the influence of genes in the lifetime is fundamental. Some species have a surprising long life (hundreds of years), while others have a very short life (less than one day); given that llifespan is fixed for each species, it is clear that lifespan is determined essentially by genes.
Why is the lifespan longer in some and shorter in others? Genes play a basic role. Hence, by revealing the secrets of gene, we may find the golden key to longevity or eternal life. Although scientists have not been able to do large-scale studies on the “longevity gene” in an organized and planned way, the bit-by-bit studies have led to many discoveries. For example, they found the gene called “I have not died”, the “Methuselah gene” and so on.
A research group in European Tumor Research Institute in Milan announced that they have found a gene related to the lifespan of an organism. By restraining the effect of such a gene, they could prolong the life of an organism. The researchers have found that after getting rid of a gene called “P66SHC” in the mouse, or restraining its functions, the mouse’s resistance to disease was strengthened and its lifespan greatly prolonged. Scientists in US Fornea Technical College found a drosophila that lives longer than other drosophilas, because there is a special gene functioning in it. Now, by using this gene they can prolong the life of drosophilas by 35%. This gene was names “Methuselah Gene”, following a figure in The Bible that lived to the age of 969. If such a gene in mankind can be found and made the best use of, we will be able to make man’s life time exceed Peng Zu - a Chinese man who lived to the age of 800 - or Methuselah. Scientists in Connecticut State University’s Medical Centre chanced on a new “longevity” gene in their research project on drosophilas. The main reason why this “longevity” gene can change drosophila’s lifespan is that it can control energy absorption of drosophila’s cells, as if they were in a “diet”. This gene is distributed on the two chromosomes of drosophila. If the gene is changed on only one chromosome, drosophila’s lifespan will extend by one time or so; but if it is changed on both chromosomes, drosophila will die of too much “diet”. This gene was named “I Have Not Died”. Scientists in Massachusetts Institute of Technology reconstructed the gene of a nematode and prolonged its life by more than a half successfully. If the nematode had two SIR2.1 genes, it that can only live for two weeks (originally it can live three weeks).
The discovery of these longevity genes has brought about a fine prospect for mankind’s longevity. At Scripps Academy of California scientists did a research on genes of old people above 90 and they found that in more than 99% of the cases genes functions of these old people were completely normal, almost like the genes of neonates. Then, why do we still get old? Researchers in Illinois University at Chicago have found one answer. They say that the secret of aging might lie in a special gene called “p21”. By starting up p21 gene, we can cause significant changes in uncountable other genes, and all these genes have something to do with aging and diseases relevant to aging.” So, there must be genes in the human body that are closely related to longevity, and by a full and deep understanding of such genes and by regulating and modifying them properly, we might be able to reach the purpose of longevity or living forever.
Genetic engineering also has a very important function: it can combine human genes, animal genes, vegetal genes or any species’ genes into one individual life. It is an earthshaking change, which may trigger the most profound and tremendous transformation, including extension of human life. As we know, some animals are long-living such as big turtles and many unicellular animals can “live forever” so long as the environment is suitable; also some plants are also long-living like ancient cypresses. If we could find the genes that help them live so long and then transplant or duplicate them for humans, or develop drugs with the same effect, then, we will open up the road of prolonging people’s life.
Genetic engineering could trigger a series of revolutions, such as the magical genetic forecast, genetic diagnosis, gene therapy, gene reconstruction and so on, all of which have displayed an extremely bright prospect for the realization of eternal life. Most “incurable diseases” such as cancer will be eradicated and AIDS will not be worth mentioning.
Genetic research has also shown that the main causes of aging might be related to the defects in the “maintenance” and “repair” systems of the human body, and such systems might be controlled by genes and therefore, by transforming or “closing” these genes, we might be able to control the aging process of mankind. For these reasons, the British scientist in charge of the genome project, asserts that it is not a hard thing for the average human lifetime to reach 1200 years or so. The continual breakthrough in gene research can not only prolong human lifespan, but also make people ageless. And as the Chairman of the Board of Directors of The Human Genome Scientific Research Company points out: “It is very likely for us to find out the headspring for keeping youth forever from our own genes. Cell replacement may be able to help people keep youth and health forever.”
(received by Anonymous and posted)