TIME Research

Humans Are Genetically More Similar to Their Fathers, Study Finds

Sorry mom

Every parent wants their child to be just like them, but new research shows that dads may have an advantage at least from a genetic standpoint.

According to a study by the University of North Carolina’s School of Medicine and published in the journal Nature Genetics, mammals use more DNA from the father than the mother when undergoing mutations — the genetic process that makes us who we are.

The researchers, led by genetics professor and senior author Fernando Pardo-Manuel de Villena, tested the genetic mutations of specially crossbred mice to see which mutations altered gene expression. Of the 80% that did, several hundred genes showed a “genome-wide expression imbalance in favor of the dad,” first author James Crowley told Science Daily. “This imbalance resulted in offspring whose brain-gene expression was significantly more like their father’s.”

The authors believe a similar bias would exist for human subjects. Pardo-Manuel de Villena called the results “an exceptional new research finding that opens the door to an entirely new area of exploration in human genetics.”

[Science Daily]

TIME Obesity

New Genes Mean the Future of Obesity Treatment Could Get Personal

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Scientists have uncovered a trove of new genetic targets that could lead to better treatments for obesity

It took the genomes of nearly 340,000 people and more than 400 researchers in two dozen countries, but we now have the most comprehensive picture so far of the genetic contributors to obesity.

Two new papers in the journal Nature describe the results of two studies that connected the obesity-related factors of body mass index (the ratio between height and weight) and fat distribution to their potential genetic drivers. The studies did not isolate specific genes—at least not yet—but identified areas in the human genome where people with different BMIs and different patterns of fat distribution varied in their genetic code. Those variants will lead scientists to the genes they code for, and eventually to how those genes work in contributing to obesity.

MORE: Healthy-Obesity Gene Found—But Genes Aren’t Everything

“I think we have so many more opportunities now to learn about the biology of obesity through genetic contributions to these traits,” says Karen Mohlke, professor of genetics at University of North Carolina and the senior author of the report focusing on body fat distribution.

Those genetic clues may yield new weight-management treatments that are both more powerful and more personalized. “What the data supports is the fact that there are a lot of different causes of obesity,” says Dr. Elizabeth Speliotes, assistant professor of internal medicine and computational medicine and bioinformatics at the University of Michigan and senior author of the paper on body mass index. “If you’re hoping for one cause of obesity, that’s not reality. What causes you to be obese is probably slightly different from what causes me to be obese.”

Currently, however, all obesity is treated pretty much the same way. With the new knowledge gleaned from the genetics of what’s driving different types of obesity, that may change.

MORE: Gym vs. Genes: How Exercise Trumps Obesity Genes

In the study involving factors contributing to BMI, Speliotes and her team discovered 97 genetic regions, or loci that account for nearly 3% of the variation among people on BMI. Of those, 56 are entirely new. Many of the regions are in areas that code for nervous system functions, or brain systems. Some aren’t so surprising—they confirm previous studies that have implicated genetic regulators of areas that control appetite, for example—but others were more unexpected. They involved regions responsible for learning, memory and even emotional regulation, hinting that some of weight and obesity may be tied to the addiction and reward pathways that help to reinforce behaviors like eating with feelings of pleasure and satisfaction. “There were definitely a lot more loci involving the brain than I would have guessed,” says Dr. Joel Hirschhorn, director of the center for basic and translational obesity research at Boston Children’s Hospital and Harvard Medical School and one of the co-authors. “That makes obesity much more of a neurobehavioral disorder than just the fact that your fat cells are more efficient or less efficient.”

MORE: Study Identifies Four New Genetic Markers For Severe Childhood Obesity

They also uncovered some truly head-scratching connections between some genetic variants that contributed to higher BMI and lower risk of diabetes, heart disease and triglyceride levels. That suggests that there may be some protective genetic factors that counteract the effects of higher BMI, and exploiting these may be an entirely new way of treating obesity.

The group that zeroed in on the genetic factors directing how body fat is distributed had similar findings. Mohlke and her colleagues looked at the waist-hip ratio and found 49 areas in the genome that varied among the participants, 33 of which were entirely new. Most of the variants involved logical processes such as the formation of HDL and LDL cholesterol, triglycerides and processing of insulin.

MORE: New Genes Identified in Obesity: How Much of Weight is Genetic?

What was interesting, however, was the fact that many of these exerted much more power on women than on men, suggesting the need to recognize gender-based differences as a critical factor in future obesity therapies.

The findings, all of the authors stress, are just the beginning of a deeper understanding of what is driving obesity in its many forms, and how best to intervene with more personalized and potentially more effective treatments. Genes, they say, only play a part in obesity, but these studies are the first step toward a better appreciation of how genes are involved in behaviors that influence what and how much we eat. “We don’t know how much impact each of these genetic loci are going to have on whether people will need different treatments,” says Hirschhorn. “But these papers provide the tools to start answering that question. It’s possible that if we know a lot more about how somebody came to be obese, then we will know more about what to do about it.”

TIME Research

23andMe Finds Genes for Motion Sickness

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The personal genomics company 23andMe has identified 35 genetic factors tied to motion sickness, according to a new study published in the journal Human Molecular Genetics.

In what the company says is the first ever genome-wide study looking at motion sickness, 23andMe was able to determine several genes that may be tied to the nausea associated with movement in a car or on a boat. Motion sickness affects around one in three people, and prior research has suggested that it could be hereditary.

The researchers, who are employed by 23andMe (or have been in the past) and own stock options in the company, used genetic data from more than 80,000 23andMe customers. They found that many of these genetic factors were involved in balance, eye and ear development and the nervous system. Overall, the effect appeared to be stronger in women.

Read more: Genetic Testing Company 23andMe Finds New Revenue With Big Pharma

The study also found links between risk for motion sickness and a greater likelihood of having migraines, morning sickness and vertigo.

It’s still unclear what the actual drivers are, and even if a person has the gene variants linked to motion sickness, it doesn’t mean they will definitely have the condition. Genome-wide association studies like the one performed by 23andMe can only find correlations, but they’re still useful strategies for finding at-risk genes.

TIME medicine

Genetic Testing Company 23andMe Finds New Revenue With Big Pharma

The company’s database of genetic information is worth $10 million to Genentech

The past two years have been a rough and transformative time for the controversial DIY genetic testing company 23andMe. At the end of 2013, the Food and Drug Administration requested that the company shut down its main service, an analysis of a person’s genome gleaned from spit samples that anyone who purchased a kit could send in, noting that interpreting human genes—understanding what changes in DNA mean, and how they contribute or don’t contribute to disease—is still too much of a black box.

But things may be looking better for the company in 2015. On Jan. 6, it announced a $10 million partnership with biotech company Genentech, which will sequence the entire genomes of 3,000 23andMe customers with a higher risk for developing Parkinson’s disease. Genentech is hoping the information will speed development of more effective drugs against the neurodegenerative disorder, in which motor nerves in the brain start to deteriorate. “What attracted us to 23andMe and this opportunity is the work 23andMe has done together with the Michael J. Fox Foundation in the Parkinson’s space,” says Alex Schuth, head of technology innovation and diagnostics for business development at Genentech. “They have built a community of individuals and their family members who have contributed DNA samples. What is unique about this cohort is that it gives us an opportunity to connect clinical data on how patients feel and how their disease is progressing, with their genomic data. That’s unique.” The 23andMe customers will be asked to sign new consent forms as part of any Genentech studies.

MORE Time Out: Behind the FDA’s Decision to Halt Direct to Consumer Genetic Testing

The agreement is one of many that 23andMe CEO and co-founder Anne Wojcicki says are in the works, and hint at the company’s most valuable asset—the genetic information on the 800,000 customers who have sent in their DNA-laden saliva since the company began selling kits in 2006. “Databases, and big data, is suddenly trendy,” says Wojcicki, “especially in health care where people are recognizing that when you have really large numbers, you can learn a lot more. I think we are leading part of that revolution.”

But for the past year, the company hasn’t been sending back health information to customers who pay the $99 for an analysis. Instead, customers are getting reports on their genetic ancestry, with the promise that when the FDA permits it again, they will receive health-related information based on their genetic profile. Wojcicki says that since the FDA action, sales of the kits have been cut by about half, and while they are slowly climbing back up, they haven’t yet reached pre-2013 levels.

Regaining that market is a top priority for 23andMe, says Wojcicki. “Everyone at the company has some kind of role, some involvement, in thinking about the FDA,” she says. “It has transformed the entire company—our product, our execution, how to think about marketing, every aspect of it.” The two entities are exchanging requests and responses, and while she hopes to have a resolution in 2015, it’s not clear yet when the health-related services will be offered.

In the meantime, the genetic information 23andMe has already collected is becoming a potential gold mine for academic researchers and for-profit drug developers. The company has more than 30 agreements with academic researchers for which they receive no monetary compensation, so that scientists can learn more about certain diseases and contribute to basic knowledge about what goes wrong in those conditions. Wojcicki says she’s balancing opportunities with both non-profit and for-profit companies to optimize the value of 23andMe’s database. “Some research has absolutely no monetary capacity, and we should still do those, because fundamentally what 23andMe does is represent the consumer,” she says. “And some research does have monetary capacity, and we should do those too. Because the reality is that the group that is going to develop a drug or treatment or therapy for something like Parkinson’s disease is going to be a for-profit company.”

Read next: These GIFs Show the Freakishly High Definition Future of Body Scanning

Listen to the most important stories of the day.

TIME Cancer

Most Types of Cancer Just ‘Bad Luck,’ Researchers Say

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JUAN GARTNER—Getty Images/Science Photo Library RF Lymphocytes and cancer cell

Two thirds of cancers could be explained as biological misfortune

Researchers have found that bad luck plays a major role in determining most types of cancer, rather than genetics or risky lifestyle choices such as smoking.

The results, published in the journal Science on Thursday, found that random DNA mutations that amass in the body when stem cells divide into various tissues cause two thirds of cancers.

After examining 31 cancer types, researchers found 22 were from mutations in stem cells that could not be prevented.

Cancers that could be explained with biological bad luck included pancreatic, leukemia, bone, testicular, ovarian and brain cancer.

But the researchers say lifestyle choices such as avoiding smoking, eating healthily and staying out of the sun will help to prevent certain cancers, just not all of them.

Read next: Medicine Is About to Get Personal

Listen to the most important stories of the day.

TIME medicine

Genetic Screening Saved This Baby’s Life

Researchers say sequencing genomes can lead to quicker diagnoses and effective treatments for more than half of children affected by brain disorders

Mya Burkhart was only six months old when she went into cardiac arrest. Fortunately, she was in the hospital when it happened, brought there by her parents because she had trouble breathing. It was her eighth or ninth visit to the emergency room for her respiratory problems, but each time the doctors had sent the Burkharts home with more questions than answers.

Mya wasn’t developing at the normal rate. She couldn’t lift her head and wasn’t responding to people and things around her. Doctors thought she might have a muscle disorder, but her other symptoms did not fit with that diagnosis.

After her heart scare, Mya spent three weeks, including her first Christmas, in the ICU on a ventilator. “I couldn’t pick her up or anything,” says her mother Holly. Still unable to solve the mystery of what was ailing her, the doctors finally suggested she have her genome tested. Maybe, they hoped, her DNA would offer some clues about why she wasn’t growing normally.

MORE: The DNA Dilemma: A Test That Could Change Your Life

Holly knew the test was still in the research stages, and that there was a chance that even it might not yield any more answers about her daughter’s condition. “At that point, I just wanted to try anything to find out what was wrong with her,” she says. It boiled down to balancing a chance that their baby would live or die.

Genetic screening, especially whole-genome screening in which people can learn about their possible risk for certain diseases, remains controversial, since the information is neither definitive nor always accurate. In most cases, genes can only predict, with a limited amount of certainty, whether a disease such as breast cancer or Alzheimer’s looms in a person’s future. As the Food and Drug Administration (FDA) contemplates the merits and efficacy of such screening, some doctors and researchers are using it with great success, according to a new study published in the journal Science Translational Medicine.

Researchers at Children’s Mercy Hospital in Kansas City, where Mya was treated, say that for 100 families, including the Burkharts, with children affected by either unknown disorders or brain abnormalities, genome screening helped 45% receive a new diagnosis, and guided 55% to a different treatment for their child’s disorder. Of the 100 families, 85 had been going from doctor to doctor in search of a diagnosis for an average of six and a half years.

“I was surprised by how many cases we found where a specific intervention can make a difference,” says Sarah Soden from the Center for Pediatric Genomic Medicine at Children’s Mercy and the study’s lead author. “For me it’s compelling enough to push the envelope and get younger kids diagnosed.”

MORE: Faster DNA Testing Helps Diagnose Disease in NICU Babies

In Mya’s case, her genome revealed a mutation in a gene responsible for transporting citrate; without it, her cells could not get the energy they needed. So far, only 13 babies have been confirmed with the condition, and all died before their first birthday after having seizures and respiratory infections. Once the genetic analysis revealed the deficiency, however, Mya was started on citrate supplements. She’s now 18 months old, having already lived nearly twice as long as the other confirmed cases. She has some developmental delays but she has not had any seizures and managed to avoid getting any serious respiratory infections.

Their success at Children’s Mercy are encouraging Soden and the study’s senior author, Dr. Stephen Kingsmore, to push ahead and determine how such screening can benefit more babies. About 5% of the 4 million babies born in the U.S. each year are admitted to the neonatal intensive care unit (NICU), and between those who are born with a genetic disorder and those who may have adverse drug interactions, he and his team anticipate that about 30%, or 60,000, may benefit from the personalized screening they offer.

For now, he and his team are targeting babies like Mya who are sick almost from the minute they enter the world, with symptoms and abnormalities that doctors simply cannot explain. For them, the screening can save families from uncertainty as well as the financial burden of having many different experts perform many different tests looking for a diagnosis. The average genetic sequencing for newborns costs around $5,000, but the average cost of a night’s stay in the Neonatal Intensive Care Unit (NICU) hovers around $8,000, and most babies spend days, if not weeks, in the units awaiting a diagnosis.

Kingsmore received a $1.5 million grant from the NIH to expand the screening program to other institutes, and he has reached out to hospitals in Florida, at the University of Maryland and in Oklahoma City to test the strategy in more babies. “If we can decrease the length of stay in the NICU it could certainly lead to huge potential cost savings,” says Dr. Alan Shuldiner, associate dean of personalized medicine at the University of Maryland.

In the latest study, Soden says that on average, families spent more than $30,000 on genetic testing alone to figure out what was ailing their babies; those who had their genomes screened paid about $3,000 for an answer.

The key to Kingsmore’s success is a system that starts with a doctor punching in a newborn’s baffling symptoms and ends with a genetic readout. The “magic juice,” as he calls it, is a database of 10,000 symptoms that typically affect infants, from simple coughs and fevers and enlarged hearts to all manner of abnormal lab readings. The baby’s unique combination of these symptoms is mapped onto the 3,000 genes that experts have so far connected to about 4,000 diseases. “No physician on the planet earth could carry that database around in his head,” says Kingsmore. But that’s what desperate parents, whose babies’ lives are at stake, expect them to do. So Kingsmore’s program accomplishes the feat, spitting out, in rank order, a list of potential genetic diagnoses. That targeted tally of diseases then directs doctors to focus on a much more manageable list of 10 or, at the most, 50 genes (from a possible 20,000 or so) that could be mutated and responsible for the baby’s condition.

While there is no argument that such testing can save lives, the more challenging question is who should be tested, and when. There is also still debate among those in the genetics and medical communities about how to interpret genomic data. “Some people would argue that he is still reporting his experimental findings, and moving too soon from the research arena into the clinical arena,” says Dr. Edward McCabe, chief medical officer of the March of Dimes.

Ethicists are concerned about the coerciveness inherent in any hand extended to parents whose babies would otherwise die; no matter how carefully and comprehensively doctors word their request, parents in that situation may not fully process the risks and benefits and be unable to provide a truly informed consent. What if the baby falls into the minority for whom the testing doesn’t yield a diagnosis or treatment? When faced with inevitable death on the one hand, and a chance, however, small, of avoiding that death on the other, can there ever really be a choice?

The stakes are especially high since in some cases, the disorders won’t lead to established and approved treatments, but experimental ones without known risks and benefits. But as the value of such testing becomes more obvious, more centers may consider sequencing more newborns’ genes. “These babies, because they are brand new, are salvageable,” says Kingsmore. “Many patients we see with genetic illnesses already have ravaged organs. In contrast, with newborn babies we have the opportunity to halt a disease early in its progression,” he says.

“I think this testing is definitely something that everybody should consider,” Holly Burkhart says. “Without it, we probably never would have figured out what was wrong with Mya. We probably would be in the same place we were a few months ago.” Instead, Mya is now smiling at her mom and making progress. “The testing helped us find answers, and tell us where we need to go from here,” she says.

TIME animals

You Always Knew Your Cat Was Half Wild But Now There’s Genetic Proof

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That kitty curled up on your lap is only one genetic step away from jungle killer

A new study on house cats has found that our feline companions are actually only semi-domesticated.

People began domesticating cats around 9,000 years ago but DNA researchers from Washington University in St. Louis found that house cats still have many of the same traits as their wild cousins. The fact that cats have retained the ability to hunt and survive effortlessly in the wild just underscores how little impact we humans have had on them.

Wes Warren, an associate professor of genomics at the university, told the Los Angeles Times, “We believe we have created the first preliminary evidence that depicts domestic cats as not that far removed from wildcat populations.”

That’s not to say humans haven’t had any influence on cats. We originally took them into our homes to hunt rodents and rewarded that behavior with food. According to researchers, this lead to eventual changes in a group of stem cells that resulted in more docile (but not fully domesticated) felines and produced colors and fur patterns that humans liked.

“Our results suggest that selection for docility, as a result of becoming accustomed to humans for food rewards, was most likely the major force that altered the first domesticated cat genomes,” researchers wrote.

Read more at the Los Angeles Times.

Read next: Celebrate National Cat Day With the Most Ridiculous Cover in TIME History

TIME Science

Looking to Science for Answers About Race

Theodosius Dobzhansky
Pictorial Parade / Getty Images Theodosius Dobzhansky, circa 1960s

How a forgotten scientist changed the way we talk about race

History News Network

This post is in partnership with the History News Network, the website that puts the news into historical perspective. The article below was originally published at HNN.

Americans are constantly reminded of the contradictions concerning the meaning and impact of race.

We can as a nation claim progress as it pertains to race. After all, a majority of American voters have twice elected President Barack Obama to the most powerful office in the world.

Yet, for as much progress as we have made there is as much work to be done. The recent killings by police of unarmed black men in Ferguson, Missouri and Staten Island, New York remind us how race shapes the often hostile relationship between law enforcement and some communities. Racist comments by several NBA owners remind us that some remain polluted by the foolish belief in the fundamental superiority and inferiority of different groups. Skin color still limits economic and other opportunities. Take home loans: over the past few years the U.S. Justice Department settled cases with several banks for having steered non-whites into expensive subprime loans despite having qualified for standard mortgages.

Race matters, of course, and so too does the meaning we give it. We have often turned to science for that meaning—to justify beliefs and to provide a vocabulary for explaining human differences. But science too struggles with understanding race.

When we talk about the scientific meaning of race today we do so largely because of the work of the distinguished evolutionary biologist Theodosious Dobzhansky, who spent most of his career at Columbia University. Though today forgotten outside of scientific circles, Dobzhansky was almost single-handedly responsible for reshaping the race concept in the 20th century through his classic book, Genetics and the Origin of Species (1937).

Until Dobzhansky’s work appeared, race was defined largely in typological terms, meaning that one member of a race was thought to share the same traits with other members of that race. This kind of thinking helped perpetuate racist actions and stereotypes. For example, from 1932-1972 the infamous Tuskegee Study followed the natural course of syphilis in African American men because it was mistakenly believed that syphilis was a different disease in blacks than it was in whites.

Although Dobzhansky was unaware of the Tuskegee Study at that time, he did understand that such classifications were bad science. Dobzhansky, through new techniques in population genetics and evolutionary biology, came to understand first in the non-human animals he studied like fruit flies and ladybug beetles, and later in humans, that genetic diversity at the racial or population level was far greater than most people knew. Racial groups were much more genetically complex than a typological race concept would allow.

So how did Dobzhansky redefine race? To Dobzhansky, race was simply a methodological tool to facilitate the scientific study of human and other populations. Race was not a fixed entity, it was a way to organize individuals within a species based on the frequency with which a gene or genes appeared in that population. Depending on the genes being investigated, there could be just a few or many races. What made his definition so important and so radical was that he understood that the way we choose to organize differences in gene frequencies within species were about data and methodology, not about an underlying racial hierarchy or about the fixity of certain traits within specific groups. Dobzhansky thus sought to extract racism from the race concept.

By the 1960s, Dobzhansky grew disillusioned with the race concept, and came to believe that the scientific study of race was not only inseparable from its broader social meanings, but that it could also be put in the service of reinforcing those social meanings. The rise of the Civil Rights Movement and his own battles with other scientists over the imprecise and often inappropriate use of the term ‘race’ led him to issue a challenge to the field: devise better and more meaningful methods to investigate genetic diversity.

More than fifty years later biology still struggles with Dobzhansky’s challenge and still operates within a paradox that he himself struggled with. On the one hand, race can be an important tool to help scientists organize genetic diversity. On the other, race is an imprecise marker of genetic diversity and not a great proxy for elucidating the relationship between our ancestry and our genes.

This paradox remains central to the use of race in our genomic age. For example, it is currently too expensive to sequence everyone’s genomes, so the rapidly growing field of personalized medicine relies on race as a proxy to make best guesses about an individual’s disease risk and how one’s genes influence the response (positively or negatively) to drug treatments. Because genetic variants can cluster in populations, the belief is that this can help clinicians and drug companies make medical decisions based on one’s race. The potential danger here is that we inadvertently reinforce a crude understanding of race, forgetting that it is a highly flawed concept that cannot be used as a proxy for an individual’s own genome.

It turns out that muddled thinking about race is as deeply ingrained in scientific as non-scientific thought, and that scientists are as conflicted about race as the rest of society. It is neither cynical nor misguided to acknowledge this. It is only a reflection of a society that continues to struggle with the meaning and impact of racial difference.

Michael Yudell, Interim Chair and Associate Professor at the Drexel University School of Public Health, is author of “Race Unmasked: Biology and Race in the 20th Century,” which was recently published by Columbia University Press.

TIME ebola

This Might Be Why Some Survive Ebola

A new mice study may help explain Ebola's varying impacts

Scientists in a biosafety level 4 lab have discovered that genetics are likely involved in how susceptible someone is to Ebola, finds a new mice study published in the journal Science.

Why some people survive Ebola and others do not, even when they’re treated in the same conditions, is a question that’s long intrigued researchers. The current outbreak has also revealed that humans show symptoms of the disease differently; a significant number do not present hemorrhagic fever symptoms like heavy diarrhea, vomiting and bleeding before death.

So far, researchers have primarily used monkeys to study the Ebola virus, but in the new study, the researchers discovered that a genetically diverse population of mice had wide variations in their responses and symptoms to the Ebola virus—similar to how humans have reacted. It’s notable because mice very rarely have similar immune responses to humans, which is why discoveries made in mouse models are evaluated skeptically.

When the researchers infected the mice with Ebola, they found that some of the mice survived with mild disease symptoms, some died, and some died with severe hemorrhagic fever symptoms similar to those observed in humans. Researchers Michael G. Katze and Angela L. Rasmussen of the University of Washington also identified a few potential genetic pathways that might differ in mice who survive the disease versus those who die from it. The hope is that these pathways could help researchers develop drugs for the disease.

“We now have a model that represents the human Ebola disease that we could test vaccines in, we could test novel therapeutics in, and we also could start getting information about the genes that are responsible for the resistance to Ebola and the susceptibility to Ebola,” said Katze in a video about the study. Before the researchers can make the leap to developing drugs for humans, they will have to confirm that the pathways also exist in humans and work in the same way. But the new research is a starting point.

The team started studying the progression of the Ebola virus in mice a few years ago, before the current outbreak of Ebola started in West Africa. Only a handful of of scientists work in the few high-security containment labs in the United States. The training, Katze told TIME, is intense and requires psychological testing. “We’ve been studying Ebola for almost a decade. We’ve always been interested in Ebola because it’s a very interesting virus. It’s like the rockstar of viruses,” Katze told TIME in early October.

Read on for more about the scientists’ emerging Ebola research.

TIME Autism

Major Autism Studies Identify Dozens of Contributing Genes

Researchers collaborate on two large studies identifying the genetic basis of autism

Two new studies exploring the genetic basis of autism tie mutations in hundreds of genes to the disease.

Several teams of researchers collaborated on the studies, both published in the journal Nature, and found that about 60 of the genes are considered “high confidence,” meaning there’s a 90% chance that mutations within those genes contribute to risk for autism. Both studies show through genomic sequencing that many of these mutations are de novo, meaning that parents do not have the gene mutation, but they present spontaneously just before a child is conceived in either the sperm or egg.

It’s long been believed that autism is genetic, but a lack of large studies and advanced genomic sequencing has precluded any sort of consensus about what genes might be at play. But in the last couple years, scientists have been able to look at the genetic mutations in hundreds of people with autism and identify genes that likely factor into a child’s development of the disorder. In the two new studies, scientists were able to expand their work and look at thousands of people.

In one of the studies, several institutions used data from the Simons Simplex Collection (SSC), which is a collection of DNA samples from 3,000 families. In each of the families, one individual had autism. The researchers compared the gene sequences of the individual with autism to their unaffected family members. After analysis, they estimated that de novo mutations contribute to autism in at least 27% of families, where only one member has the disorder.

The other study, by researchers at 37 different institutions as part of the Autism Sequencing Consortium, looked at 14,000 DNA samples of parents with affected children. It found 33 genes the researchers say definitely increase risk for autism, should there be a mutation.

Even though there may be hundreds or even thousands of genes that contribute to a child’s risk of developing autism, the researchers on both studies found that the mutations appear to converge on a much smaller number of biological functions, like nerve-cell communication or proteins known to cause inherited disability. “In my view, the real importance of these studies is not diagnosis, and it’s not figuring out exactly what percentage of people have de novo mutations, it’s about laying the foundation to transform the understanding of the biological mechanisms of autism,” says Dr. Matthew State, chair of the psychiatry department at University of California, San Francisco and a co-leader of the SSC study, as well as a senior participant on the other study.

State doesn’t believe that the findings will mean that families will one day get their genomes sequenced to spot hundreds of possible mutations. Instead, they could lay the groundwork for discovering how autism develops, and what potential treatments, or even drugs, could help fight it.

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