Wednesday, January 22nd, 2014
The extent to which toddlers exhibit aggressive behaviors like hitting, kicking, or biting may be associated as much, if not more, with genetics than environment, according to a new study conducted by researchers from the University of Montreal. More from Science Daily:
“The gene-environment analyses revealed that early genetic factors were pervasive in accounting for developmental trends, explaining most of the stability and change in physical aggression, ” [researcher Eric] Lacourse said. “However, it should be emphasized that these genetic associations do not imply that the early trajectories of physical aggression are set and unchangeable. Genetic factors can always interact with other factors from the environment in the causal chain explaining any behavior.”
Over the past 25 years, research on early development of physical aggression has been highly influenced by social learning theories that suggest the onset and development of physical aggression is mainly determined by accumulated exposure to aggressive role models in the social environment and the media. However, the results of studies on early childhood physical aggression indicate that physical aggression starts during infancy and peaks between the ages of 2 and 4. Although for most children the use of physical aggression initiated by the University of Montreal team peaks during early childhood, these studies also show that there are substantial differences in both frequency at onset and rate of change of physical aggression due to the interplay of genetic and environmental factors over time. Genetically informed studies of disruptive behavior and different forms of aggression across the lifespan generally conclude that genetic factors account for approximately 50% of the variance in the population.
Lacourse and his colleagues posited and tested three general patterns regarding the developmental roles of genetic and environmental factors in physical aggression. First, the most consensual and general point of view is that both sources of influence are ubiquitous and involved in the stability of physical aggression. Second, a “genetic set point” model suggests a single set of genetic factors could account for the level of physical aggression across time. A third pattern labeled ‘genetic maturation’ postulates new sources of genetic and environmental influences with age. “According to the genetic maturation hypothesis, new environmental contributions to physical aggression could be of short duration in contrast to genetic factors,” Lacourse explained.
Image: Aggressive toddler, via Shutterstock
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Thursday, September 5th, 2013
A new series of US government-funded studies investigating the possibility of screening the entire genome of newborn infants is raising excitement among some parents, concern among others. At issue is whether such DNA mapping would help parents prepare and cope with their kids’ health conditions, or whether the tests would provide more information than parents can reasonably be expected to handle. NBC News has more:
Do parents even want to know what fate might await their babies? Can doctors find out anything useful medically? Do you get information that freaks you out? All over the country, thousands of newborns will be enrolled in this experiment, the National Institutes of Health announced on Wednesday.
They’re not necessarily looking for new diseases in the babies yet, says Dr. Eric Green, director of the NIH’s National Human Genome Research Institute (NHGRI). They want to know what happens if you even go down this road of whole-genome sequencing.
Now’s the time, he said, as companies begin offering these tests on the market and as more and more people seek to find out just what their genes say about their health. “Everything is moving so fast,” Green told reporters on a conference call.
“We really want to take advantage of this window of opportunity to answer key questions about the technical, ethical, social implications while we have a chance to do it,” Green added. “If it turns out this is something that is worth doing, we would answer questions about how to make it most effective.”
Green’s genome institute and the National Institute of Child Health and Human Development (NICHD) has set aside $25 million for the next five years to study the matter, starting out with $5 million to four institutions: Brigham and Women’s Hospital and Boston Children’s Hospital; Children’s Mercy Hospital in Kansas City; the University of California, San Francisco and the University of North Carolina at Chapel Hill.
Each center will take a different approach. For example, UCSF will test blood drops previously collected from 1,400 California children who were already given newborn screening tests. Boston Children’s will recruit 480 newborns starting early next year, giving half the standard screening and half an extra genome test.
Most of the 4 million children born in the U.S. each year get a heel-prick test that takes a drop of blood to screen for genetic diseases such as phenylketonuria, sickle-cell disease, cystic fibrosis and thyroid disorders. The precise panel differs from state to state but usually covers around 30 disorders.
One reason to do the tests, says NICHD director Dr. Alan Guttmacher, is to intervene early, before the child gets sick. Phenylketonuria or PKU is a classic example. It’s an inability to process an amino acid called phenyl lanine, which can build up in the brain and cause permanent damage. “By knowing the baby has the disease early, parents can modify the baby’s diet to remove phenylalanine and prevent damage,” Guttmacher said. “Prevention is the only effective solution.”
The heel-prick tests cost around $100. Whole-genome screening covers not only known genetic defects, but the entire DNA map. Commercial tests – which don’t look at every stretch of DNA – cost about $5,000.
Image: Infant getting blood test, via Shutterstock
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Wednesday, August 21st, 2013
Children who have a big brother or big sister with an autism spectrum disorder face an increased risk of developing such a disorder themselves, according to a new study in the journal JAMA Pediatrics. The study, of more than 1.5 million children in Denmark, found that sibs of kids diagnosed with autism had an almost seven-fold increased risk of developing autism as well.
This research comes on the heels of a recent study that found that women who undergo labor induction may be more likely to give birth to children with autism spectrum disorders.
Here’s more on the sibling study from TIME.com:
For parents, the findings raise difficult questions about how proactive they should be in screening for the disease among their younger children if older siblings are affected. Alycia Halladay, senior director, environmental and clinical sciences for Autism Speaks, says parents who have already had a child diagnosed on the spectrum should alert their doctor to the family history. During check-ups, when a doctor asks about inherited disorders like cystic fibrosis, they now typically include autism on the check-list.
Mothers of autistic children can also take steps during pregnancy to lower the risk of autism in their next offspring, such as taking prenatal folic acid and avoiding overexposure to toxins. That attention could even extend to the infants’ first few years, since studies suggest that some intensive behavior therapies can help to mitigate the symptoms of autism. “We know that early intervention can make a real lifetime of difference. So be very vigilant during that child’s life, all the way from birth to the well baby check-ups, six months, 12 months, and 18 months,” says Halladay. “Make sure you are watching for the signs and symptoms of autism. Consult your pediatrician, and if you do notice the signs and symptoms of autism you can receive help free of charge from a state-based early intervention agency.”
Researchers are also developing tests that can detect the genetic risk factors associated with the disorder, and more of these biomarkers may become available as additional gene-based contributors emerge. Scientists from University of Utah and the Children’s Hospital of Philadelphia, for example, recently identified 24 new gene variants associated with autism spectrum disorders in January.
Image: Toddler and baby, via Shutterstock
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Monday, August 12th, 2013
Mothers with a specific gene that makes them more prone to stress during times of transition and uncertainty may be more likely to treat their children harshly or abusively during times of economic downturn, according to a new analysis of data from the Fragile Families and Child Wellbeing Study. CBS News has more:
Moms who had a variation in a gene called “DRD2 Taq1A genotype” were shown in a new study to be more likely to react negatively to economic changes in their environment compared to moms who didn’t possess the variant.
The DRD2 Taq1A genotype has been shown to control how the body creates dopamine, a neurotransmiter that regulates behavior in the reward-based pathway in the brain.
The researchers looked at data from the Fragile Families and Child Wellbeing Study (FFS), which included almost 5,000 children born in 20 U.S. cities between 1998 and 2000. The mothers were interviewed after giving birth, and when their child was 1, 3, 5 and 9 years of age. Information on parenting behavior was gathered when the child was 3, 5 and 9 years old.
Harsh parenting was determined by the mother’s score on the Conflict Tactics Scale, which included questions on five items on psychological harsh parenting — like shouting or threatening the child — and five more items on corporal punishment, like slapping or spanking.
Saliva DNA samples were also collected from 2,600 mothers and children when the child was nine to test for the genetic variant.
After gathering the data, the researchers took into account the economic conditions where the subjects were living, focusing on unemployment rates. They then discovered that moms who had the “sensitive” allele or variation of the DRD2 Taq1A genotype — which they called the “T allele” — were more abusive towards their children when the economy was bad, such as during the 2007-2009 Great Recession. Mothers without this genetic variation were no more likely to act harshly towards their children during this time.
When economic situations improved, mothers with the sensitive T allele were not as harsh compared to the other mothers.
They also discovered that high levels of unemployment among the subjects did not increase how abusive a mom was. Mothers with the T allele were more likely to be mean with their children when the economy was bad, even if they personally did not lose their job or had any personal changes because of the recession.
Instead, the overall unemployment rate of the city they lived in and their confidence in the economy played a larger role. A 10 percent increase in the overall unemployment rate was linked to a 16 percent increase in maternal harsh parenting among those with the T allele.
Image: Angry mother and daughter, via Shutterstock
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Wednesday, August 7th, 2013
The urge to smoke may be genetic, according to new research published in the journal Pediatrics. Fox News has more:
In a study published in the journal Pediatrics, researchers discovered that the children of people who smoked only in their teenage years were still 3.2 times more likely to also pick up the habit, compared to children whose parents had never smoked.
For the study, researchers gathered data from a sample of ninth grade students in St. Paul, Minn. They followed this group from 1988 through age 38 – and then also gathered data from the children of that cohort, starting at age 11.
Overall, they found the rate of smoking was 23 to 29 percent among kids ages 11 and older whose parents had once smoked or currently smoked, compared with 8 percent among children of parents who had never smoked, MedPage Today reported. Children who had older siblings who smoked were also more likely to smoke, researchers reported.
“We don’t know exactly what’s going on here, but my hypothesis is that there is a genetic predisposition toward smoking,” Dr. John Spangler, a family and community medicine specialist at Wake Forest Baptist Medical Center in Winston-Salem, N.C., told MedPage Today. “Whether it is a genetic predisposition toward risk taking behavior, genetic disposition toward experimentation of substances, or even a genetic disposition toward nicotine addiction itself.”
Spangler went on to say that parents shouldn’t take the findings as a reason to give up trying to stop their kids from taking up the habit. He urged parents to talk to children about the dangers of smoking, and encourage healthy lifestyle habits to help parents stop, and kids never start, smoking.
Image: Cigarettes and pacifier, via Shutterstock
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