dna

Posted on December 16, 2024December 13, 2024 Diet

You are what you eat…and so are your grandkids? Study links poor diet to multi-generational health issues

Study finds how the effects of famine can be passed from one generation to the next.

You are what you eat, as the adage goes. However, a new study from Tulane University found that what’s missing from your diet may also impact the health of your descendants across multiple generations.

Recent research supports the idea that famine in one generation can lead to harmful genetic outcomes in the next. However, questions about how many generations could be affected when an ancestor endures a nutritional crisis have persisted.

In a study published in Heliyon, Tulane researchers found that when paired mice were fed a low-protein diet, their offspring had lower birthweights and smaller kidneys over the next four generations, leading risk factors for chronic kidney disease and hypertension.

Researchers found that correcting the diets in offspring had no impact, and subsequent generations continued to be born with low nephron counts, the vital filtration units that help kidneys remove waste from the bloodstream. Though further work remains to determine if the findings translate to humans, the outcomes underscore the potential for food scarcity or malnutrition to result in decades of adverse health outcomes.

“It’s like an avalanche,” said lead author Giovane Tortelote, assistant professor of pediatric nephrology at Tulane University School of Medicine. “You would think that you can fix the diet in the first generation so the problem stops there, but even if they have a good diet, the next generations – grandchildren, great-grandchildren, great-great-grandchildren – they may still be born with lower birth weight and low nephron count despite never facing starvation or a low-protein diet.”

Correcting the diet in any of the generations failed to return kidney development in offspring to normal levels.

While maternal nutrition is crucial to an infant’s development, the study found that first-generation offspring were negatively impacted regardless of whether the mother or the father ate a protein-deficient diet.

This novel finding of how diet can have a transgenerational impact on kidney development is one of the latest in the field of epigenetics, the study of how environmental factors can impact gene expression without changing the DNA sequence.

The researchers studied four generations of offspring with nephron counts beginning to show signs of normalizing by the third and fourth generations. Tortelote said further research is needed to determine which generation returns to proper kidney development – and why the trait is passed on in the first place.

“The mother’s diet is absolutely very important, but it appears there’s also something epigenetically from the father that governs proper kidney development,” Tortelote said.

The study also illuminates further understanding of the underlying causes of chronic kidney disease, the eighth leading cause of death in the U.S.

“If you’re born with fewer nephrons, you are more prone to hypertension, but the more hypertension you have, the more you damage the kidney, so it’s a horrible cycle and a public health crisis that could affect people across 50 to 60 years if we apply this to humans’ lifespans,” Tortelote said. “There are two main questions now: Can we fix it, and how do we fix it?”

Posted on August 22, 2019August 22, 2019 Autism

Study identifies 69 genes that increase the risk for autism

UCLA-led team compares DNA of children with the disorder to that of their siblings and parents

A UCLA-led research team has identified dozens of genes, including 16 new genes, that increase the risk of autism spectrum disorder. The findings, published in the journal Cell, were based on a study of families with at least two children with autism.

Researchers from UCLA, Stanford University and three other institutions used a technique called whole genome sequencing to map the DNA of 2,300 people from nearly 500 families. They found 69 genes that increase the risk for autism spectrum disorder; 16 of those genes were not previously suspected to be associated with a risk for autism.

Researchers also identified several hundred genes they suspect may increase the risk of autism based on their proximity to genes previously identified to carry an increased risk. The study analyses further revealed several new biological pathways not previously identified in studies of autism.

The findings shed light on how genetic variants or mutations — the differences that make each person’s genome unique — are passed from parents to children affected with autism, said the study’s co-lead author Elizabeth Ruzzo, a UCLA postdoctoral scholar. Former UCLA postdoctoral scholar Laura Pérez-Cano is the study’s other co-lead author.

“When we look at parents of autistic children and compare them to individuals without autism, we find that those parents carry significantly more, rare and highly damaging gene variants,” Ruzzo said. “Interestingly, these variants are frequently passed from the parents to all of the affected children but none of the unaffected children, which tells us that they are significantly increasing the risk of autism.”

Of the children in the study, 960 have autism and 217 children do not. That enabled researchers to analyze the genetic differences between children with and without autism across different families.

“Studying families with multiple children affected with autism increased our ability to detect inherited mutations in autism spectrum disorder,” said Dr. Daniel Geschwind, senior, corresponding author of the study and the Gordon and Virginia MacDonald Distinguished Professor of Human Genetics, Neurology and Psychiatry at the David Geffen School of Medicine of UCLA.

“We show a substantial difference between the types of mutations that occur in different types of families, such as those that have more than one affected child versus those having only one child with ASD,” said Geschwind, who also was the study’s co-principal investigator and director of the UCLA Center for Autism Research and Treatment and director of the Institute of Precision Health at UCLA.

The research also found that the 16 genes newly determined to be associated with an increased risk for autism form a network with previously identified ASD risk genes. The way they interact with one another further heightens the risk, said the study’s co-senior author and co-principal investigator Dennis Wall, a Stanford University School of Medicine associate professor of pediatrics and of biomedical data science.

“They associate with each other more tightly than we’d expect by chance,” he said. “These genes are talking to each other, and those interactions appear to be an important link to autism spectrum disorder.”

The nearly 600 genes researchers suspect as carrying an increased risk of autism were identified through “guilt by association,” or through their interactions with other genes that already have been shown to carry an increased autism risk, Ruzzo said.

“And although not all of those genes will be found to increase the risk for autism, our analysis indicates that future studies will provide support for many of these genes,” she said.

The families studied are part of the Autism Genetic Resource Exchange (AGRE), which was originally developed nearly two decades ago by researchers and the National Institutes of Health in collaboration with Cure Autism Now, which is now a program of Autism Speaks.

Autism is a spectrum of neurological disorders characterized by difficulties with communication and social interaction. Geschwind has been working to identify the genetic causes and biological mechanisms of the disorder for more than a decade, and led the original development of the AGRE resource that was used in this study in the late 1990s. In 2018, he and colleagues at UCLA received their second, five-year grant from the NIH to expand autism research by studying genetic causes of autism in African American families.

SEE ORIGINAL STUDY

Leave a comment Posted on February 11, 2019February 12, 2019 Autism

DNA changes in sperm might help explain autism

DNA and Autism

[Original article on NHS Choices website]

“DNA changes could explain why autism runs in families, according to study,” The Independent reports. Research suggests a set of changes in a father’s DNA – known as methylation – is linked to autism spectrum disorder (ASD) in their offspring.

Methylation is a chemical process that can influence the effects of genes on the body (gene expression), essentially turning off certain genes. This process can lead to both positive and negative changes in DNA. These types of changes are known as epigenetic changes.

In this small study of 44 men and their offspring, researchers scanned for epigenetic changes at 450,000 points on the DNA molecule. They compared the DNA results with the child’s score on an ASD prediction test at one year of age, and then looked for regions of DNA where changes were linked to a higher or lower risk of ASD.

The researchers found 193 areas of DNA from the men’s sperm where methylation levels were associated with a statistically significant increased risk of developing ASD.

Researchers hope the study will help them see how epigenetic changes might affect ASD risk. At present, there is no genetic test for ASD and the causes are poorly understood. The study suggests ways ASD risk could be handed down in families without specific gene mutations being involved.

We’re still a long way from understanding the causes of ASD, and many cases can occur in children with no family history of the condition, but this study gives researchers new avenues to explore.

Where did the story come from?

The study was carried out by researchers from Johns Hopkins University and Bloomberg School of Public Health, the Lieber Institute for Brain Development, George Washington University, Kaiser Permanente research division, the University of California and Drexel University.

It was funded by the US National Institutes for Health.

The study was published in the peer-reviewed medical journal the International Journal of Epidemiology.

Both The Independent and Mail Online covered the study well, explaining the research and outlining its limitations.

What kind of research was this?

This was an observational study that compared changes to the chemicals attached to DNA in father’s sperm (epigenetic changes) with early signs that a baby may go on to develop ASD.

It also looked at the DNA of people who had died to see whether the same changes were associated with having ASD.

This small study investigated links between epigenetic changes and the risk of ASD among children whose parents already had at least one child with the condition. However, it can’t tell us whether these DNA changes cause ASD.

What did the research involve?

Families who already had at least one child with ASD and where the mother was pregnant with another child were enrolled into the study.

The researchers took sperm samples from 44 fathers. 12 months after the babies were born, they were tested for early signs suggesting they might have ASD.

The researchers analysed the sperm samples and looked for differences between the DNA of the fathers whose children’s test results showed a higher risk of ASD, and compared them with those at lower risk.

They chose to study families with at least one child with ASD, because the condition is thought to run in families. They wanted a group of children who were more likely than the general population to have ASD, so they could do a smaller study and still get useful results.

The babies were tested using the ASD Observation Scale for Infants (AOSI). This test does not show whether or not the babies have ASD. It looks at behaviour such as eye contact, eye tracking, babbling and imitation, and gives scores from 0 to 18, with a higher score meaning the baby is at higher risk of having ASD.

Other studies have found that babies with high AOSI scores at around 12 months are more likely to be diagnosed with ASD when they get older, but the test is not a 100% effective screening tool.

The fathers’ sperm was analysed for epigenetic changes – these are changes to the chemicals attached to the DNA molecule, but not the genes themselves. These chemicals can affect how the genes work.

In this case, researchers looked for methylation of DNA. They used two different methods of analysing sperm, so they could check the accuracy of the primary method.

The researchers used a technique called “bump hunting” to search for regions of DNA where the levels of methylation were associated with the AOSI scores of the children.

Once they had identified the regions, they looked at DNA in samples of brain tissue taken from people after death, some of whom had ASD, to see if they could spot similar patterns.

What were the basic results?

The researchers found 193 areas of DNA from the men’s sperm where methylation levels associated with AOSI scores were statistically significant. In 73% of these regions, an AOSI score showing a higher risk of ASD was linked to lower levels of methylation.

Looking at these regions, the researchers found they overlapped genes that were important for the formation and development of nerve cells and cell movement.

They also found some – but not all – of the DNA regions identified as important in sperm analysis could also be associated with having ASD in DNA taken from brain tissue.

How did the researchers interpret the results?

The researchers say they saw a strong relationship between epigenetic changes and increased chances of having ASD within this group of children. They said the difference in methylation was “quite substantial” and concentrated in areas of DNA associated with nerve cell development.

They point to a region of DNA that contains a group of genes thought to cause Prader-Willi syndrome, a genetic condition that has some similarities to ASD but is much rarer (affecting no more than 1 in every 15,000 children). This was one of the regions strongly associated with epigenetic changes.

The researchers say the results suggest that epigenetic changes to the father’s DNA in this region “confer risk of autism spectrum disease among offspring, at least among those with an older affected sibling”.

Conclusion

This study found that epigenetic changes to a father’s DNA seem to be linked to an increased chance of his child developing ASD in families where there is already one child with the condition.

ASD tends to run in families, and some studies have identified genes that may increase the chances of developing the condition. However, there is no clear genetic explanation in most cases of ASD. Research like this helps scientists to investigate other ways that the condition could be handed down.

The study raises a lot of questions. It can’t tell us what causes the epigenetic changes to the DNA, or how they affect the way DNA works. Also, when the researchers looked at epigenetic changes to DNA in people’s brains, they didn’t find changes in many of the regions identified in the sperm analysis.

This was a fairly small study, relying on only 44 sperm samples. The researchers themselves say the results need to be confirmed in larger studies. We also can’t say whether these results would apply to the general population. They may only be valid for families where one child already has the condition.

Learning more about the genetics of ASD will hopefully lead to new treatments. This study may offer up one more piece of a very complicated, yet-to-be-solved, puzzle.

Leave a comment Posted on January 30, 2018January 30, 2018 Weight Loss

Weight Loss and DNA – “Are These Genes Too Tight?”

DNA and weight loss

71% of women that have dieted are currently unhappy with their weight with one in five admitting they are constantly dieting

Over a third say it doesn’t matter what they do they can’t lose weight and 59% are yet to find a successful way to manage their weight

Hope for serial dieters as evidence suggests DNA tests can reveal how your body uniquely responds to exercise, food and drink; whether an individual has the so-called ‘Fat Gene’

January is a peak time of the year for dieting, yet conversely, it’s also a bit of a peak time for quitting a diet. Frustration at not seeing the desired results after a few weeks can lead to many new-found dieters jumping straight off the bandwagon and back on the road toward unhealthy eating habits.

New research suggests that one in five women across the UK are constantly on a diet in one way or another, with 59% saying they’ve never found a way to control their weight.

So, perhaps the issue lies deeper within the make-up of the individual. In fact, the answers to how and why so many are failing diets could be held within our DNA. Very simple, non-intrusive DNA tests can tell us more about how our bodies process foods, giving an individualized perspective on what would work best for that person.

The discovery of a so-called ‘Fat Gene’ can lead to uncontrollable urges to snack and eat more than the average person. DNA tests can help identify the way each body stores and processes fats, assess risks from the likes of cholesterol and triglycerides as well as honing in on nutritional needs that should be focused on when planning a diet.

With a further 35% of women re-gaining their initial weight loss after a mildly successful diet, it seems apparent the need for a more permanent solution is greater than ever. Becoming even more evident as the research, commissioned by LloydsPharmacy, also reveals that a quarter of women feel they have ‘no control over their weight’ and a fifth are ‘at the end of their tether’ trying to deal with weight issues.

In the studio to discuss how our genes and DNA could be the key to unlocking dieting ideals are Dr. Lior Rauchberger and Dr. Dhiren Bhatt.

Leave a comment Posted on March 13, 2017March 14, 2017 Genetics, Patient Talk

What testing your DNA can tell you

Do I need to test my DNA?

Good question.

A fair few medical conditions have a genetic component. Breast cancer and celiac disease for two example.

Them there are other condition like autism where the jury is still out but it does seem a strong possibility!

So it can be worth checking. This infographic gives you a bit more information on DNA testing should you chose to do so!

From Visually.