Un calcio... di salute - Blog del Benessere

Chi si interessa di salute e benessere sa già quanto sia importante assumere le giuste quantità dicalcio per prevenire l'osteoporosi. Ma ora dalla letteratura scientifica arrivano nuovi dati che allargano il raggio d'azione del calcio. Uno dei dati più recenti e interessanti riguarda il rapporto fra calcio assunto con la dieta e longevità, approfondito dai ricercatori del Karolinska Institutet di Stoccolma. Per gli autori dello studio, un apporto di calcio superiore a quello giornaliero raccomandato potrebbe ridurre la mortalità per tutte le cause.

Altri studi suggeriscono, invece, che basse assunzioni di calcio possano rappresentare un fattore di rischio importante per altre patologie, come la preeclampsia, l'ipertensione e il cancro del colon. Altre novità dalla ricerca riguardano il possibile ruolo del calcio nel ridurre l'aumento di grasso intra-addominale nella premenopausa e nell'alleviare i sintomi della sindrome premestruale.

Ma quanto calco dobbiamo assumere ogni giorno? Secondo i Larn (Livelli di assunzione raccomandati di nutrienti (elaborati dalla Società Italiana di Nutrizione Umana), il fabbisogno deve essere particolarmente elevato in età evolutiva, con un massimo nell’adolescenza e deve mantenersi elevato fino ai 29 anni circa ovvero fino a quando è possibile aumentare la massa scheletrica. Nell'età adulta, quando ormai si è raggiunto il picco di massa ossea, le necessità si abbassano a 800 mg al giorno. Durante la gravidanza e l’allattamento si consiglia ovviamente di aumentare l'assunzione di calcio per prevenire il depauperamento del patrimonio minerale della donna. Anche nell'anziano, in cui si registra una riduzione dell’assorbimento, si consiglia di aumentare la quota di calcio ingerita per ridurre la perdita di massa ossea.

DNA analysis for disease risk isn’t catching on among consumers

Connected to Google by both love and money, 23andMe seems the epitome of a 21st-century company — a cutting-edge merging of biotechnology and the Internet, with a dash of celebrity thrown in.

The scarce ingredient so far is customers.

23andMe is the most prominent of a trio of companies that in 2007 began using the Web to market personal genomics services. The companies scan people’s DNA, promising to tell them their risks of getting dozens of diseases. Propelled by its co-founder Anne Wojcicki, the wife of Google’s billionaire co-founder Sergey Brin, 23andMe attracted attention by holding swanky “spit parties” where people gave saliva samples for DNA analysis. Rich and famous people like Rupert Murdoch, Harvey Weinstein and Ivanka Trump became customers and in some cases investors.

But for the common consumer, 23andMe’s service — and those from its main competitors, Navigenics and DeCode Genetics — have been a much harder sell. Two and a half years after beginning its service, 23andMe has only 35,000 customers. And at least one quarter of them got the service free or for only $25, instead of the hundreds of dollars on which the business model is based. Navigenics and DeCode have even fewer customers.

The low turnout suggest that many people have not yet embraced the genomics age. It does not help, either, that the services cost $300 to $2,000 and have been trying to catch on during a severe recession.

But the services face an even more fundamental problem: In most cases, the current level of DNA scanning technology and science is unable to offer meaningful predictions about the risk that a person will get a disease.

“It is a really wonderful form of recreation,” said Scott R. Diehl, a geneticist at the University of Medicine and Dentistry of New Jersey. But as for applying it to health care, he said, “It’s very premature.”

The companies have been forced to adjust. Named for the 23 pairs of human chromosomes, 23andMe went through two rounds of layoffs last year. The company, which is privately held and based in Mountain View, Calif., has fewer than 40 employees, down from a peak of about 70. Navigenics, based in Foster City, Calif., is on its third chief executive in a year and has also trimmed its workforce. It is now marketing to doctors and corporate wellness programs rather than consumers.

People close to the company estimate that Navigenics has about 20,000 customers, at least 5,000 of whom were given big discounts to be in a study.

And DeCode Genetics, based in Iceland, passed through bankruptcy following heavy spending to develop drugs and diagnostic tests. The DecodeMe personal genomics service, while only one part of the company’s business, apparently attracted fewer than 10,000 customers.

Multiple Common Variants for Celiac Disease Influencing Immune Gene Expression

Celiac.com 03/11/2010 - As part of an effort to investigate the possibility of multiple common variants for celiac disease influencing immune Gene Expression

The process by which a gene\'s coded information is converted into the structures present and operating in the cell. Expressed genes include those that are transcribed into mRNA and then translated into protein and those that are transcribed into RNA but not translated into protein (e.g., transfer and ribosomal RNAs).'); return false" style="color: rgb(80, 136, 1); text-decoration: underline; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; ">Gene Expression, a team of more than sixty scientists recently worked together to conduct a second-generation genome-wide association study (GWAS) of 4,533 individuals with clinically proven celiac disease, along with 10,750 control subjects.

They genotyped a total of 113 selected SNPs with PGWAS <>

The GWAS included five European sample collections of celiac disease and control cases, including the celiac disease dataset reported previously. The team's stringent data quality control measures included calling genotypes using a custom algorithm on both large sample sets and, where possible, cases and controls together. The team tested 292,387 non-HLA

Human Leukocyte Antigen - elicit the strongest immunologic response in the body, and chromosome 6 is the genetic region that codes for these antigens. The genes that encode the class II molecules DQ2 and DQ8, the key genetic risk factors in celiac disease. Because the HLA complex is inherited intact as two haplotypes (one from each parent), siblings have 1 in 4 chance of being HLA-identical.'); return false" style="color: rgb(80, 136, 1); text-decoration: underline; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; ">HLA SNPs from the Illumina Hap300 marker pool for association in 4,533 individuals with celiac disease and 10,750 control subjects of European descent. They also tested another 231,362 additional non-HLA markers from the Illumina Hap550 marker set for association in a subset of 3,796 individuals with celiac disease and 8,154 controls. All markers came from autosomes or the X chromosome. For both datasets, Genotype call rates were >99.9%.

The study showed over-dispersion factor of association test statistics comparable to that observed in other GWASs of this sample size. Factoring in missing genotypes for 737 cases with celiac disease genotyped on the Hap300 BeadChip and corresponding controls did not change the findings in any meaningful way. Variants from 13 new regions reached genome-wide significance (Pcombined < class="HelpLink" href="javascript:void(0)" onclick="">T-cell

A small lymph cell created in the thymus which orchestrates the immune system\'s response to infected or malignant cells. Also known as a T lymphocyte.'); return false" style="color: rgb(80, 136, 1); text-decoration: underline; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; ">T-cell selection.

The data suggested associations for 13 additional regions. Expression quantitative trait meta-analysis of 1,469 whole blood samples showed that 52.6% of tested loci (20 of 38 loci) had celiac risk variants corresponding with cis gene expression (P <>

Source: Nature Genetics

Medicine’s Future Could Lie in Each Patient’s Genome

Two separate scientific teams announced this week that they had successfully sequenced individual genomes to pinpoint precise genetic causes of illness — breakthroughs that open the door to a future of individualized, genomics-based medicine.

“This is another milestone in the inevitable march towards personalized genetic health,” said Dr. Robert Marion, chief of genetics and development medicine and director of the Center for Congenital Disorders at Children’s Hospital at Montefiore Medical Center in New York City. “Medicine is going to change from waiting for symptoms to develop to knowing what this person is at risk for and being able to stop that from happening. Eventually, we’re talking about prevention.”

One day in the future, Marion predicted, doctors will be able to look at all 20,000 or 25,000 genes in a newborn baby and be able to say whether the child has specific genetic disorders, or a twofold increased risk of developing colon cancer or a higher chance of developing childhood asthma.

And the cost to perform such feats has come way down, with experts at one company predicting that genomes could one day be sequenced for as low as $5,000. Right now, the cost hovers closer to $50,000.

“When it gets to the point where it would cost less to sequence the genome using these techniques than it does to send off a sample to test for a few genes, then you can start moving medicine from just seeing people who are sick to trying to prevent people from getting sick,” said Dr. Jeffery Vance, director of the Center for Genomic Medicine at the Hussman Institute for Human Genomics, University of Miami Miller School of Medicine. “You can see where things are going. This is showing that it’s practical, it can be done and that medicine will start slowly to move toward using this technique as a diagnostic technique for all these individuals and families who have what looks like an inherited disease but not a big family history.”

And, Vance pointed out, genes don’t change like cholesterol and blood pressure do. These tests would only have to be performed once.

The predictions are based on breakthroughs reported this week in two journals, the New England Journal of Medicine and Science.

Dr. James Lupski, vice chair of molecular and human genetics at Baylor College of Medicine in Houston, was both the lead author and the subject of the NEJM study. Lupski suffers from a genetic disorder, Charcot-Marie-Tooth syndrome, which affects nerve function.

By sequencing his genome, the NEJM authors were able to trace the disorder to mutations in copies of the SH3TC2 gene he and three siblings inherited from healthy parents.

For Lupski, who already knew he had this disease, the findings probably don’t come as much of a shock. But suppose people don’t know they have this or another single-gene conditon?

In the old days — meaning last week — experts would have had to suspect which disease the patient had, then hone in on the area of the genome thought to be associated with the disorder. Even then, the results could be far from certain.

“The breakthrough is that now we would be able to make this diagnosis without having any preconceived idea that the patient had Charcot-Marie-Tooth disease,” Marion said.

The second team of researchers sequenced the genomes of two parents and two children from the same family with single-gene diseases. They reported that only 60 of the three billion base pairs in the human genome mutate randomly each generation. That’s about half the rate of mutation that was thought to be passed generation to generation.

How were scientists able to make these leaps?

One big factor has been the advent of new technology with the ability to sequence large amounts of DNA very quickly, explained Marion. Previous technology could only analyze bits of material at a time.

For now, the technology is likely to be helpful only with single-gene disorders which, when it comes to genetics, are relatively easy targets.

“It becomes more difficult with complex disorders because these disorders are not due to one single gene but a combination of genetic factors in multiple genes, as well as environmental factors,” said Marion, author of Genetic Rounds: A Doctor’s Encounters in the Field that Revolutionized Medicine.

“For single-gene disorders, this technology is a breakthrough,” he continued. “But for the more complicated polygenomic or multifactorial conditions, which is every condition that affects humans — diabetes, blood pressure, coronary artery disease and cancer — there’s a complex interplay between multiple genes and the environment. And sorting that out using the technology we have available now is still not possible.”

“Right now, it has its biggest effect where one of the 25,000 or so genes we have by itself doesn’t work right,” Vance agreed. “It won’t have much effect on common diseases like cancer and Alzheimer’s.”

Another expert agreed that the breakthrough could have its limits.

“This showed that there’s tremendous variability between individuals, and if you’re a cup-is-half-full kind of guy, this creates wonderful possibilities for the concept of personalized medicine,” said Richard H. Finnell, professor of environmental and genetic medicine at Texas A&M Health Science Center Institute of Biosciences and Technology in Houston.

“But if you’re a cup-is-half-empty kind of guy, we’ve been treating a lot of disorders with aspirin for a heck of a long time without differentiating individuals or even necessarily knowing what the mechanism of action of a drug is and [still] gotten some benefit,” he noted.

But, for many patients, an accurate diagnosis will at least be a move in the right direction.

“If you were the parent of a child with a disorder and you had taken your child to doctor after doctor after doctor and were given either no diagnosis or a vague diagnosis, to even have a clear-cut diagnosis that doesn’t come with an intervention, that’s a huge step forward and a great relief,” Finnell said.

In the meantime, traditional genome-wide association studies, which compared the genomes of people who had a disease with people who didn’t have the disease, are going to be “left in the dust,” Marion said.

More information

Learn more about genetics at the Human Genome Project.

By Amanda Gardner

Personal look at genes locates disease causes

Children inherit about 30 mutated genes from each parent, fewer than had been thought, but enough in at least one case to pass on inherited illnesses, according to a first detailed look at the blueprint for human life in a family.

And a separate study of an individual genome located the cause of another inherited disease. The blueprint for life, called DNA, contains about 22,000 genes, and researchers calculated the number of changes by analyzing the genes of a mother, father, and their son and daughter. The result, reported in Thursday’s online edition of the journal Science, found that the children had about 30 mutations from each parent for a total of 60 changes passed along to the offspring.

Scientists previously had thought a child had about 75 mutated genes from the parents. The rate of mutations probably will vary somewhat, depending on the age of the parents, said co-author Lynn B. Jorde, chairman of the Department of Human Genetics at the University of Utah School of Medicine. Most mutations are thought to be unimportant, but the rate at which things change is considered critical, helping explain the gradual development of changes.

Genomic studies can help researchers find ways to identify individual genes or mutations that can lead to inherited disease. Jorde and the senior author, David J. Galas, of the Institute of Systems Biology in Seattle studied a family in which the parents had no genetic abnormalities, but each carried recessive genes that resulted in their son and daughter being born with two extremely rare conditions — Miller’s syndrome and primary ciliary dyskinesia.

Miller’s syndrome, which causes facial and limb malformations, has been diagnosed in only two families in the world. PCD is a condition in which the tiny hair-like structures that are supposed to move mucus out of airways in the lungs do not function. The chances of having PCD are estimated at one in 10,000. Jorde said the odds of someone having both PCD and Miller’s syndrome are less than one in 10 billion. “We were very pleased and a little surprised at how much additional information can come from examining the full genomes of the same family,” Galas said in a statement.“ Comparing the sequences of unrelated individuals is useful, but for a family the results are more accurate. We can now see all the genetic variations, including rare ones, and can construct the inheritance of every piece of the chromosomes, which is critical to understanding the traits important to health and disease,” he said.

The family was not named in the report. Meanwhile, a separate report in the New England Journal of Medicine disclosed that Dr. James Lupski of Baylor College of Medicine had sequenced his own complete genome and identified the gene involved in his form of Charcot-Marie-Tooth syndrome, which affects the function of nerves in the body’s limbs, hands and feet. Lupski, vice chairman of molecular and human genetics, said the work “demonstrates that the technology is robust enough that we can find disease genes by determining the whole genome sequence. We can start to use this technology to interpret the clinical information in the context of the sequence — of the hand of cards you have been dealt.” “Isn’t that the goal or dream of personalized genomic medicine?” he said in a statement.Lupski said he has known for 40 years that he had a disease caused by recessive genes. Now he knows the gene at fault.

And Lupski and colleagues found that having a single copy of the recessive mutation is susceptible to carpal tunnel syndrome, which usually affects people who perform repetitive motions that compress a nerve where it crosses the wrist.