MD-Writer Blog

Can we improve our mood, ward off three serious diseases, and avoid infections by taking a single inexpensive pill? Perhaps we can with vitamin D. The buzz about the vitamin seems to get louder by the day. The fact that this subject of medical news is a cheap, widely available tablet suggests it’s not just hype spun a company seeking to boost sales.

Several reports on possible benefits of the vitamin have appeared in just the last few weeks. In late February, medical researchers in the U.K. published a meta-analysis of research on the relationship of vitamin D blood levels to a group of illnesses they called “cardiometabolic disorders,” which included cardiovascular disease, diabetes, and metabolic syndrome. The scientists pooled 28 studies involving 100,000 middle-aged and elderly adults and found a 43% reduction in these of illnesses among those with the highest levels of the vitamin.

This week, doctors and scientists in Copenhagen showed that vitamin D supports the immune response of T-cells to cellular antigens. T-cells are white blood cells involved in cellular immunity, the part of the immune system that recognizes and eliminates invasive organisms, such as viruses, that reside within the body’s cells. T-cells can also distinguish and destroy cancer cells.

The Danish research, which was covered by both Scientific American and ScienceDaily, found that vitamin D participates in a critical step in transforming T-cells from silent sentinels on the watch for invasive organisms into messengers that sound the alarm and killers that attack compromised cells. As explained by one of the scientists who did the research:

When a T cell is exposed to a foreign pathogen, it extends a signaling device or ‘antenna’ known as a vitamin D receptor, with which it searches for vitamin D. This means that the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they won’t even begin to mobilize.

A T-cell recognizes danger when it contacts a foreign antigen on the surface of another type of white cell, called a macrophage, which ingests invaders or cancer cells. The contact then triggers the gene for the antenna, which forms a complex with vitamin D. If the T cell has sufficient quantities of the vitamin, then another gene gets triggered, and its product activates the T-cell and transforms it into an immune fighter.

In January, scientists in Montreal reported that the vitamin also participates in another crucial immune function. It supports the recognition of harmful bacteria by monocytes, epithelial cells and macrophages in the intestine. These important components of the immune system secrete an antibacterial substance in response to contact with muramyl dipeptide, a chemical pattern found on the surface of many bacteria.

There’s also evidence that vitamin D counters depression. Two years ago, researchers in Amsterdam reported that vitamin D levels averaged 14% lower in people with minor and major depression among a large Dutch cohort of more than 1000 persons participating in a long-term epidemiological survey. In line with this discovery, medical researchers at the Loyola University Health System in Chicago announced plans this week for a trial to learn whether vitamin D supplements would improve the mood of women in that city, where harsh winters often keep people indoors and out of the sun.

Vitamin D is synthesized in the skin in response to sunlight. But in America (as well as much of the rest of the developed world), exposure to sunlight is insufficient to produce enough of the vitamin. As a result, three-quarters of Americans may be vitamin D deficient, according to research done as part of a national survey of Americans’ health.

Distrust of government was the topic this morning when William Galston, a Brookings Institution scholar, appeared on C-SPAN’s Washington Journal. He discussed his opinion piece in the Financial Times on Wednesday.

Galston wrote and spoke about the attitude of Americans toward their government, as reflected in a CBS News/New York Times poll in February. In the FT article, he commented:

Only 19 per cent of respondents – near the record low – said they trusted the government to do what is right all or most of the time. Only 29 per cent thought they had much influence on what the government does, while 78 per cent believed the government to be run by a few big interests, not for the benefit of the people.

Suspicion of government goes back to the founding of the Republic, Galston said. But in the era that began with the New Deal through the early Johnson administration, trust of government was high, reaching 76% in 1964. Then, the government enacted large programs, including social security, banking regulations, civil rights, and Medicare for older Americans. But following the Vietnam War and Watergate, trust in government plummeted to 36% in 1974 and stood at just 17% when President Obama took office.

This morning the callers to the C-SPAN program confirmed the abysmal assessment of our government. Few spoke on behalf of government; most spoke very skeptically, and some decried it with vitriol.

Although Galston didn’t make precisely this connection, I think it’s almost certain that distrust of government is the major cause of political polarization and impotence in Washington and the nation at large.

Deep distrust of what government says and does causes uncertainty and confusion. Lacking leaders whom they believe, people turn to their predispositions and biases, especially the most strident and partisan. Polarization and dissension grow and the ability to compromise—and enact compromises—fails. Impotence and paralysis take hold, as the government loses the ability to govern.

Last month Fareed Zakaria, the CNN commentator, spoke about the huge financial challenges facing the country. He used the counterexample of one official who acted decisively and restored some trust in government. Paul Volker, the former Fed chairman, carried through the deeply unpopular tightening of credit that curtailed inflation in the early 1980s. Zakaria spoke about a similar need to enact “deeply painful” measures to fix the nation’s current economic woes, like raising taxes and limiting entitlement benefits. He asked whether politicians today were capable of taking necessary difficult, unpopular positions, as Volker did.

Government will not be able to carry out essential changes without holding the trust of the people. And trust will not come unless government carries out essential changes. It is a desperate cycle that the leaders of our nation must break. They must act and succeed. The people cannot do it themselves. Only when our leaders succeed in achieving what they must, will they merit the confidence that Paul Volker once earned.

Whether we trust them or not, our fate now is in the hands of our leaders and our government.

Actually, this may be a question that liberals prefer not to discuss, since it entails the possibility of attributing a less admirable trait to a class of people, those with conservative values, which may seem like prejudice. But to be truthful, I’ve always thought that the answer to this question is probably yes. Now, Satoshi Kanazawa, an intrepid social psychologist at the London School of Economics and Political Science, has produced a study (pdf) in the current issue of Social Psychology Quarterly that supports the idea.

Before describing the results of his careful research, which uses precise definitions, I want to explain what I mean by “liberal” and why I suppose liberals are probably smarter. I think mostly in political terms, and to me a liberal is someone who generally votes Democratic, or perhaps Green. Liberals value political equality, equal rights, and equal economic opportunity, and we back government initiatives to level the playing field among people of different economic strata, ethnic and religious groups, genders, and sexual orientations. We are concerned about the unfortunate and underprivileged among us, and we support a strong social safety net, including government assistance to poor people.

Central to the liberal worldview and value set is the recognition that we live in a complex society, and that while we can certainly affect our own position in the social system with respect to power and fortune, there are also potent influences beyond our control—especially the social position and genetic endowment that we were born with.

Being liberal, I believe, involves recognizing and understanding the many complex factors contributing to each person’s unique situation. That requires intelligence, education, and a lot of thought. Hence, liberals tend to be smarter.

Kanazawa, however, has gone much further than armchair speculation. He examined intelligence, along with political attitudes and values (as well as other attitudes and values) in the findings of the National Longitudinal Study of Adolescent Health and the General Social Surveys. The former is a survey headquartered at the University of North Carolina and begun in 1994 of 132 high schools and middle schools and 20,000 students. The latter are annual and biennial surveys of 1500-3000 adults carried out by the National Opinion Research Center at the University of Chicago.

The author drew the definition of liberal from survey questions that included self-identifications on scales of liberal/centrist/conservative values on the survey of adolescents and young adults and liberal vs. conservative values on the survey of adults. Intelligence was assessed using the Peabody Picture Vocabulary Test on the adolescent-young adult survey and a verbal synonym test on the adult survey.

The results were striking in the younger group. Intelligence increased monotonically with liberal self-identification, and the most liberal respondents scored 0.8 standard deviation higher on intelligence than the most conservative. So it’s pretty clear that at least among the young, IQ correlates with liberalism.

On the adult survey, the results were less dramatic but still highly significant. Positive correlation of liberal views with intelligence was assessed using a standardized coefficient to be 0.07, with p < .001.

Kanazawa explains his result with reference to a hypothesis called the Savanna-IQ Interaction, which supposes

more intelligent individuals may be more likely to acquire and espouse evolutionarily novel values, such as liberalism, atheism, and, for men, sexual exclusivity, than less intelligent individuals, while general intelli- gence may have no effect on the acquisition and espousal of evolutionarily familiar values.

In the course of his research, he shows that the novel cultural values likely to have appeared recently in human history—liberalism, atheism, and marital fidelity among men—correlate with intelligence. In contrast, several values long extant in human culture, because of their central role in enhancing survival—values related to the importance of children, marriage, family and friends—do not correlate with intelligence, i.e., they are present to about the same degree in more and less intelligent people.

Naturally, being liberal, I find the outcome of Kanazawa’s research satisfying and validating. Yet I’m not entirely happy simply accepting his results. For one thing, I think it would be mistaken to assume that people with conservative and traditional values are not intelligent. Kanazawa examined averages of groups of people. Clearly, there are/were many exceptional people who give counterexample to his findings—extremely intelligent conservatives (like William Buckley), and dumb liberals and atheists (whom I will refrain from naming).

Finally, we need to keep in mind that there are many kinds of intelligence, not just the verbal and IQ kinds. Howard Gardner, the Harvard education professor, has described nine kinds. I’m particularly impressed by his notion of interpersonal intelligence, the ability to understand other people. As I’ve grown older, I’ve realized how very important for life that kind of intelligence is. Even though I’m quite intelligent in the IQ sense, I’m average in the interpersonal sense, perhaps below average.

And I wouldn’t be surprised if conservatives and traditionalists, as a group, scored higher on interpersonal intelligence than liberals do.

Do toxic chemicals in the environment cause autism? Nicholas Kristof of the NY Times asked that question in his column last week. The number of children with autism spectrum disorders has been rising for several years. Kristof’s concern was provoked by a report last month in the journal Current Opinion in Pediatrics. The article, authored by a professor at Mount Sinai School of Medicine, reviewed evidence that linked autism to substances in the environment. The abstract says:

Indirect evidence for an environmental contribution to autism comes from studies demonstrating the sensitivity of the developing brain to external exposures such as lead, ethyl alcohol and methyl mercury. But the most powerful proof-of-concept evidence derives from studies specifically linking autism to exposures in early pregnancy – thalidomide, misoprostol, and valproic acid; maternal rubella infection; and the organophosphate insecticide, chlorpyrifos. There is no credible evidence that vaccines cause autism.

Late last year, the CDC presented a summary of the results of its Autism Surveillance Survey, which showed a 57% rise in the prevalence of this group of developmental disorders, which may severely impair social, intellectual and behavioral functioning of children.

The surveyors used telephone interviews to sample ten communities nationwide in 2002 and 2006. They asked questions regarding the presence of an autism spectrum disorder (ASD) among 8-year-old children. An average of 9 children per 1000, slightly less than 1%, had an ASD. Comparing the two years, nine of ten communities showed an increased ASD prevalence, ranging from 27% to 95%, averaging 57%.

The increase was found all groups of children—boys, girls, and all races, ethnic groups, and cognitive-function groups. But boys were affected more than four times as frequently as girls, and the increase in prevalence was 25% greater in boys.

Although some of the rise might come from improved detection and recognition of ASD, the agency commented, “A true increase in risk cannot be ruled out. We know there are multiple complex genetic and environmental factors which result in multiple forms of autism and we have much to learn about the causes.”

In a similar vein, last September in the journal Environmental Health Perspectives a report on phthalates appeared. These are substances used in many plastics and cosmetics.

Phthalates have been controversial in recent years because they are thought possibly to disrupt endocrine functions, particularly in young children. Phthalates are not chemically bonded within the products in which they occur, and the chemicals may leach into skin, liquids in plastic containers, and the environment.

The September article in the environmental journal reported correlations between phthalate metabolite concentrations in maternal urine samples taken in third trimester of pregnancy and subsequent poor scores of the children on assessments of variety of behavioral abnormalities—aggression, conduct problems, attention problems and depression.

So many chemicals are used in modern technological societies! In my view, it would not be surprising that some of the medical and behavioral disorders of children that are increasingly prevalent in recent years are caused or exacerbated by toxic effects of some of these chemicals.

The Europeans have made more progress than Americans in investigating the huge variety of synthetic substances used in manufactured products. In 2007, the European Commission began implementation of REACH, a regulation requiring “the Registration, Evaluation, Authorisation and Restriction of Chemical substances.” The law aims to “to improve the protection of human health and the environment through the better and earlier identification of the intrinsic properties of chemical substances.”

If America will not move forward as aggressively as Europe in this regard, we can at least hope that we may have the European data on which to base our decisions.

Neuroscientists have demonstrated that the focusing of attention in consciousness is associated with specific frequencies of neuronal activity in the brain, and anticipation of an event requiring attention is associated with other specific frequencies.

The researchers, at the University of Chicago, Baylor College of Medicine, and Rush University, showed that one person’s conscious attention to instructions displayed on a computer screen was signaled by the onset of beta oscillations (12-30 Hz) of local field potentials in his motor cortex. They also demonstrated that delta oscillations (0.5-1.5 Hz) in the same region indicated the subject’s enhanced readiness to focus attention on an anticipated instruction.

The research was reported last Thursday in the journal Neuron. An article on the findings appeared in ScienceDaily the next day.

The subject of the experiment was a quadriplegic person, whose brain had been implanted with a computer chip holding an array of 100 electrodes. The device allows paralyzed individuals to control the motion of a computer cursor with their brain. However, the chip also permits recording of local field potentials similar to brain waves on an EEG.

In the experiment the subject watched a rhythmic sequence of five instructions to move the cursor, as they appeared on the computer screen. But the person was told to carry out only the second and fourth instructions. The recording from the electrode showed that the amplitude of beta frequency brain waves increased as the subject waited for the relevant instructions to appear, and the beta amplitude peaked just before they did. The beta amplitude subsided between the relevant instructions, when the subject was ignoring the other instructions not performed.

The electrode recordings also showed that the amplitude of delta frequency waves entrained to a periodicity that followed to the timing of the appearance of the instructions. The scientists inferred that the delta waves play a role in enhancing a readiness to pay attention, so that maximum beta activity would coincide with the appearance of the anticipated input.

The relationship of the two frequencies is like the melody and bass of a tune, one scientist explained. “The slow rhythm is kind of like the rhythm section, and you anticipate notes at particular moments in time based on that slower rhythm,” he said.

The researchers hope that the ability to track a person’s attention could help people to improve their concentration. In the case of paralyzed people connecting with computers, attention monitoring might help to improve their control of the computer.

The discovery also clarifies an important issue regarding the nature consciousness. Brain scientists sometimes fail to distinguish between consciousness, an inclusive concept, and attention, a specific function of consciousness. For example, we sometimes say that we become conscious of a particular feeling or thought. We don’t mean that we are not already conscious, but rather a feeling or thought comes to our attention—we notice it.

An article touching on this issue appeared last December in Scientific American. Daniel Bor, a neuroscientist and author of the report, wrote in a comment: “Some researchers suggest that attention and consciousness are one and the same, in fact. A very interesting question.”

The new research points to the answer by demonstrating that particular brain waves in the beta frequencies are associated with the function of attention. Yet the contemporaneous occurrence of delta waves also shows that consciousness is present, whether or not the function of attention is engaged. (Of course, the fact that the subject was alert and responsive (conscious) during beta amplitude troughs also shows that consciousness is distinct from attention.)

This difference was graphically illustrated in the first episode of the Charlie Rose’s remarkable series of programs on brain research. One of the brain scientists, Tony Movshon, used the Necker cube to demostrate that the brain can synthesize two alternative perceptions of one diagram of a cube. In experiencing this familiar but striking optical illusion, we discover that as we shift our function of attention, we see one version of the cube, then the other. But our function of consciousness remains with us all the time, and the two perceptions occur within our one consciousness.

Diabetic mice lacking pancreatic ß-cells that make insulin have been successfully treated with the hormone leptin alone. The leptin treatment, administered by implanted infusion pumps, normalized mice’s blood glucose levels and and other diabetic abnormalities. In addition, leptin lowered fatty acid blood levels, and it corrected abnormalities of lipid levels induced by insulin treatment that promote insulin resistance and atherosclerosis.

Leptin is the hormone secreted by fat cells that has stirred widespread interest because of its effect on the appetite centers of the brain to reduce appetite and regulate weight.

The report of the new research appeared yesterday in PNAS, the journal of the National Academy of Sciences. Medical scientists at the University of Texas, Duke, Albert Einstein College of Medicine, and the VA North Texas Health Care System demonstrated these remarkable effects of leptin using mice whose insulin-secreting cells had been chemically destroyed. They are now planning a clinical trial of combination insulin/leptin therapy in diabetic people. (Because insulin is a mandatory life-sustaining treatment for type I diabetes, clinical trials of leptin alone would not be permitted, at least initially.)

The new hormonal treatment appears to work because of the action of leptin to suppress glucagon, another metabolic hormone secreted by the pancreas. Insulin and glucagon have opposing effects on blood glucose. Insulin stimulates the cells of the body to take in the sugar from the blood as the main source of energy. This reduces glucose levels in the blood.

In contrast, glucagon increases blood glucose by promoting synthesis of the sugar in the liver and stimulating the breakdown into glucose of glycogen, the starch stored in the body’s cells. Thus, blood glucose levels are raised in the blood either by insufficient insulin or glucagon secretion. The researchers showed that that effect of leptin in controlling blood glucose could be mediated by its effect on glucagon, because they found that glucagon levels were suppressed 80% in leptin-treated animals in comparison to those treated with insulin and saline-treated controls.

Insulin also increases blood fatty acid levels, fat storage and abnormalities of fat metabolism that promote atherosclerotic disease of the cardiovascular system. In contrast, leptin treatment normalized these lipid abnormalities. The scientists determined that these effects of insulin did not happen in the absence of glucagon secretion, and leptin treatment may have prevented them from occurring due to its suppression of glucagon.

Glucose levels were controlled at least as well by leptin as by insulin in the diabetic mice. Glucose levels in the leptin mice averaged 88 mg/dl (a normal level in humans); iin the insulin mice glucose averaged 160 mg/dl (a somewhat elevated level in humans). The variability of blood glucose on leptin was less than on insulin, perhaps showing that glucose control was superior in the leptin group. Both leptin and insulin prevented the most severe effects of type I diabetes: ketoacidosis, wasting and death. And both normalized glycocylated hemoglobin A1c levels, a clinical marker of glucose control.

Leptin also substantially decreased the food intake of the mice. Leptin-treated mice ate 72% less than untreated diabetic mice and 15% less than insulin-treated mice. But the scientists showed that weight loss in the leptin mice resulted from loss of body fat, but lean tissue was spared.

These findings raise great hope that a superior treatment of insulin-dependent diabetes may be developed. Nevertheless, demonstrating the effectiveness of a new therapy in animals is always far from proving it in humans.

The potential of this new hormonal treatment is that it could revolutionize and improve the therapy of the most severe form of diabetes. We should keep our fingers crossed.

In a research report published last month, NASA climatologists collated data on emissions from burning fuels in 16 sectors of the nation’s economy and entered the data into a computer climate model. The result yielded estimates of the effect of each sector on climate warming.

The emissions in the model included CO2, NO, methane, ozone, sulfates, nitrates, black carbon (soot), organic gasses, and aerosols (fine droplets). The economic sectors included road transportation (mostly petroleum-based), household fuel burning (including fossil fuels and biomass like wood), animal farming (a source of methane), electric power generation (coal, petroleum, hydro), industry and manufacturing, and several others.

A few of the results are surprising.

In the near term (now until 2020), road transportation is the largest contributor to emissions that warm the climate by adding heat-trapping gasses to the atmosphere (not very surprising). Unexpectedly, industrial fuel burning is and will remain a net cooler of the climate in the decade to come. Factories emit aerosols, including sulfates, nitrates, and organic molecules that reflect sunlight and prevent warming.

A similarly unanticipated finding is that biomass burning from forest fires and forest clearing for agricultural purposes is cooling the climate at the present time. Forest burning emits a lot of black carbon, which blocks sunlight from reaching the ground.

Power generation emits the largest amount of warming gasses at the present time, and it is a significant contributor to climate warming. But because burning coal and other fuels for power also emits reflective aerosols, the net effect of power generation on climate heating isn’t as great as road transportation.

Cooling due to factory emissions, forest burning, and power generation, however, provides only cold comfort. These emissions degrade air quality and cause serious and severe health problems. They must be cut to protect health and reduce forest loss. In the coming century, the cooling effects of these sources of emissions will be eliminated and their net warming effects will increase. By 2100, power generation will become the largest contributor to global warming, followed by road transportation and industrial fuel burning.

In the near term, the NASA research shows that the largest contribution to reducing emissions would come from downsizing the road transportation sector. Doing so would cut warming emissions without significantly affecting cooling aerosols. Nadine Unger, the lead NASA scientist on the research, put it this way:

“Targeting on-road transportation is a win-win-win,” she said. “It’s good for the climate in the short term and long term, and it’s good for our health.”

Increasing use of rail transportation to replace car commuting and truck freight would seem like the way to go.

In this connection, a new PBS series, Blueprint America: Beyond the Motor City aired last month. It’s a remarkable documentary showing how Amercans’ wholesale adoption of the automobile for transportation destroyed urban life in the 20th century—an epoch that might justifiably be called the Automobile Century.

It explains how our love affair with the car, the massive construction of roads, and the resulting flight of families to the suburbs destroyed the economic basis of cities. It also impoverished the remaining city residents, causing urban blight, segregation in ghettos, and racial riots. And it’s still going on.

Now the new NASA report makes it clearer that ubiquitous use of the automobile for personal transportation and use of trucks for freight—which was promoted by federal policies supporting highways and freeways and neglecting rail—has also probably been the main driver of global warming for the last hundred years.

Passing health care reform is not a game of chess. In a way, that’s too bad, because the president reminded me of the stories of legendary chess masters who could play a dozen games of chess at the same time and win them all. He debated every objection of each Republican, pointing to health care facts, legislative rules, and common sense ideas.

Who won the health care summit yesterday? The question was asked by a number of news analysts last evening. Was it the Democrats or the Republicans? Actually, it was President Obama, personally. He demonstrated command of the forum, competence as the leader of his party, and comprehension of the health care issue. He maintained a civil and personable demeanor for himself and conveyed that tone to the meeting as a whole, which might otherwise have degenerated to a political brawl.

The political fight, however, remains undecided as yet. The outcome depends on whether the summit provided wavering Democrats enough of political rational and support for those in the House to pass the Senate bill and for those in the Senate to pass through reconciliation a few fixes favored by the House.

During the meeting, the president said simply that he did not intend to start over and spend another year of his presidency negotiating health care. At bottom, that is what the Republicans are asking him to do. Acceding to this demand—when so many in both chambers of Congress have labors long and hard and come so close to succeeding—would be gross political incompetence and malpractice.

Angela F. Braily defended the notorious rate increases averaging 25% this year, which her health insurance company, Anthem Blue Cross, planned for its individual policyholders. She said,

We believe this was the most prudent choice, given the rising cost of care and the problems caused by many younger and healthier policyholders dropping or reducing their coverage during tough economic times. By law, premiums must be reasonable in relationship to benefits provided, which means they need to reflect the known and anticipated costs they will cover.”

Braily is the CEO of Anthem, a California subsidiary of Wellpoint, the for-profit insurance conglomerate. She is quoted this morning in the NY Times.

At the same time as healthy young adults are dropping her policies, she explained, charges for services of doctors, hospitals, drug companies, and other suppliers are increasing, and the population her company serves is aging and needing more care.

No one can doubt the fundamental truth of her explanation. Funny thing, though, these circumstances are exactly what justifies health care reform and show why her company and other for-profit companies aren’t well-adapted to cope with the surging health care costs and needs of Americans.

The primary obligation of a profit-making public company, like Wellpoint, is to protect and increase the value of the equity held by its stockholders, who own the company. Wellpoint must direct Anthem to produce a profit from the policies it sells. The company cannot choose to forego rate increases because times are hard, people are hurting, and health care needs are rising. To do so would violate the fiduciary obligation that Wellpoint owes to its owners.

But what would happen if new insurance regulations under health care reform prohibited such huge increases? Then Wellpoint executives would have no choice. They could forgo increases of that magnitude and still satisfy their obligations to shareholders. (Although the value of their stock might drop and their executives might not command such high salaries.

And suppose health care reform created a the option of buying coverage from public insurance plan, which could postpone big rate increases in hard economic times, because it would be non-profit and have no obligations to stockholders? Then Wellpoint executives would have to compete with that public plan and postpone or limit premium increases. They could forgo increases of such magnitude and still satisfy their obligations to their stockholders. (Although they might not be able to send their executives to lavish retreats costing millions of dollars each year.)

The health care summit the president has organized for today will give both Democrats and Republicans an opportunity to discuss fundamental problems with our American health care system. I will be watching to see whether one of the problems that gets discussed is the inherent conflict of interest between making a profit and providing affordable care of many health insurance companies like Anthem.

The genetic basis of many diseases is well-established and has been recognized for centuries at least and probably for millennia. Single-gene disorders are caused by a mutation in a single gene and an abnormal protein into which its mutated DNA gets translated. Examples include autosomal dominant disorders, like Huntington’s Disease; autosomal recessive ones, like sickle cell anemia; and sex-linked conditions, like hemophilia. In each case, a single protein functions abnormally. Polygenetic disorders involve several abnormal genes and the production of several abnormal proteins. Examples of such diseases include Type II diabetes and peptic ulcer disease.

But in the last decade it’s become clear that many genetic diseases may be associated with regions of the genome that don’t translated to proteins at all. An article this week in NatureNews reports that a mutation of an untranslated stretch of DNA on chromosome 9, one that is known to be associated with heart disease, causes an increased risk of atherosclerosis, the common form of cardiovascular disease involving the build up of fatty plaques in the arteries.

The mutation in the non-coding DNA, it turns out, affects two genes that do get translated into proteins. Researchers at Lawrence Berkeley National Laboratory deleted the mutated non-coding DNA in an equivalent region of the mouse genome. Aortic muscle cells from mice with the deletion made less of two proteins and multiplied much more rapidly. The reason was that the two proteins inhibit the multiplication of muscle cells in the walls of blood vessels (as well as other tissues). Such an effect might cause the growth of tissue blocking blood flow to the coronary arteries.

Over 90% of the DNA of the human genome is not translated into proteins. It was assumed to be nonfunctional DNA, consisting of remnant of once-functional genes, and has sometimes been called “junk DNA.”

In recent years, however, scientists have discovered that some non-coding DNA may get conserved in evolution—i.e., the frequency of mutations may be low, which suggests that it may serve important functions. Many non-translated genes have been found to have a regulatory function, serving as sites for the binding of proteins that control the translation of the coding DNA.

In the case of the non-coding DNA reported in NatureNews, the stretch of DNA is located more than 100,000 base pairs away from the protein-coding genes that it affected. It used to be thought that one gene produced one protein. But it’s now clear that this was a great oversimplification. Much of the genome that was thought to be junk does not get translated but does serve important functions.