Autism Risk Linked To Age Of Father
This article was published more than 15 years ago. Some information may no longer be current.
Men who wait until after the age of 40 to father children are far more likely to have offspring with autism than those who have kids before the age of 30, according to a new study.
The older dads are six times more likely to have autistic children than the younger ones, researchers found.
The mother’s age does not appear to have an influence on the likelihood of autism.
“We believe that our study provides the first convincing evidence that advanced paternal age is a risk factor for autism spectrum disorder,” said Abraham Reichenberg, a researcher in psychiatry at the Mount Sinai School of Medicine in New York.
While the biological mechanism is not entirely clear, he said, the phenomenon could be due to genetic mutations in sperm-producing cells “associated with advancing age” or changes in genetic imprinting in older men.
It is also possible that the increase in autism among offspring of older men may be due to socio-cultural factors, Dr. Reichenberg said.
Autism and related conditions, known under the catch-all term autism spectrum disorders, have become increasingly common in recent years.
The soaring numbers are due to a combination of factors, including greater awareness, changes in diagnostic criteria and, perhaps, an increase in children born with the disorder.
Can Drug Use Cause Autism
There is no medication or illegal drug taken before or during pregnancy that in itself causes babies to be born with ASD.
Certain genes are likely required for ASD and are triggered by various environmental factors that raise the risk of developing ASD.
As an example of environmental factors, the risk of ASD is higher for children with older parents, as well as those with mothers in worse general health before pregnancy. In fact, a womans age and health seems to play a more critical role than the drugs she takes.
Why Are Moms Of Autistic Kids More Prone To Depression
Dr. Dan Gottlieb of Philadelphia’s NPR station WHYY commented on the study. To paraphrase, he suggested that mothers who feel they can never do enough for their child with autism are likely to suffer from depression.
Certainly, that feeling of never being good enough could increase the risk of experiencing depression. And in some cases, individual counseling for moms could be tremendously helpful.
But while feelings of guilt and inadequacy certainly are at play for many parents, there’s much more to the story. Families, even those with children at the “upper” end of the autism spectrum, cope with many other significant issues that could lead, at the very least, to frustration, anger, irritability, anxiety and more. These examples could increase the risk of experiencing depression:
If you have symptoms of depression, see your primary care provider or a mental health provider. You may also ask a trusted friend or relative to monitor you for these signs and encourage you to get help if they occur.
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Importance Of Father’s Age
A major study conducted in Sweden looked at 2.6 million children born between 1973 and 2001. After controlling for many other possible causes, the researchers found that fathers older than 45 at the time of the child’s birth are 3.45 times more likely to have children with autism.
Additional studies have, in general, supported Reichenberg’s original findings that older fathers are more likely than younger fathers to have children with autism. But these findings don’t tell the whole story because additional studies have linked autism in children with advanced age in mothers, as well.
Fetuses Of Momm3m4 Have Increased Neuronal Loss Lack Of Astrocyte And Microglia Maturation Compared To Fetuses From Momwt
RNA sequencing of the fetal brain showed that 10/91 differentially expressed genes were those involved in Ca2+ or cation channel function indicating potential neuronal pathology in Fetusm3m4 from Momm3m4 . Ingenuity pathway analysis of MomWTFetusm3m4 vs. Momm3m4Fetusm3m4 fetal brain differential transcriptomes revealed cell death and survival, neuron development and apoptosis and seizures as the topmost Disease and Function pathologies . Reduced immunohistochemistry staining for NeuN showed a significant decrease in mature neurons in the brain of Momm3m4Fetusm3m4 compared to MomWTFetusm3m4 . In addition, significantly reduced Doublecortin staining in Momm3m4Fetusm3m4 compared to MomWTFetusm3m4 suggested loss of neurons in pups undergoing gestation in Momm3m4 consistent with our RNA-Seq findings . In correlation, serotonin staining was significantly decreased in Momm3m4Fetusm3m4 compared to MomWTFetusm3m4 .
Fig. 4: Increased neuronal loss and lack of glial cell maturation in Fetusm3m4 undergoing gestation in Momm3m4 compared to those in MomWT.Fig. 5: Schematic summarizing the effect of maternal genetics on fetal neurodevelopmental processes.
The impact of maternal genotype on in-utero gene transcription in the offspring is evident in fetal neuropathology and postnatal ASD-like behavior.
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How Could Parental Age Be Linked To Autism
There is no clear explanation for the connection between parental age and autism. There are, however, a number of theories about the connection. A few include:
- Genetic mutation: The cells in males that produce sperm for semen are exposed to more potential toxins as a man ages and may acquire more mutations during this time.
- Social issues: If parents are older when they reproduce, it may be because they took longer than most people to find a mate. This may be an indicator of social difficulties that suggest high-functioning autism .
- Socioeconomic level: In general, older parents tend to be wealthier than younger parents. This suggests that older parents may be more likely to seek autism evaluations for children with relatively mild symptoms.
Can Autism Be Passed From Mother To Son
The findings fit with a theory called the female protective effect, which holds that it takes more genetic factors to lead to autism in women than it does in men. In this case, women who have mild traits of autism may pass down autism-related gene variants to their children, without having autism themselves.
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What Did The Research Involve
The researchers obtained the records for all births in California between January 1990 and December 1999. Cases of autism were identified from this cohort using the records from routine examinations called the Early Start Report for children under three, and the Client Development and Evaluation Report for children over three.
A diagnosis of autism was defined as either a checkmark for autism under Developmental Disabilities on the ESR, or an autism level of one on any CDER record, or an ICD code for autistic disorder. Diagnosis data were available through to the year 2006. After excluding children from multiple births and those with missing data on parental age and education, there were 12,159 cases and 4,935,776 controls.
The researchers used this data to construct models of the relationship between parental age and autism risk, which were adjusted for the potential confounders of the parents race or ethnicity, their number of previous pregnancies and births, year of birth, insurance type and sum of parental education . Parental age at birth was split into categories of under 25 25 to 29 30 to 34 35 to 39 and over 40.
Paternal And Maternal Age Both Implicated
While early studies identified the negative impact of the father’s age, most recent studies have found a connection between advanced age in both parents and the likelihood of having children with autism, including:
- One large study of over 7.5 million births in California affirming the impact of paternal age nevertheless concluded that an increase in the age of the maternal parent had greater implications for ASD risk than an increase in the same number of years in the age of the paternal parent.
- A 2017 meta-analysis of 27 studies found that an increase of 10 years in maternal and paternal age was associated with an 18% and 21% higher risk of autism.
- Another large study of over 4.9 million births in California concluded that while older parents, in general, increase the risk of autism, “advanced maternal age, rather than paternal age, may pose a greater risk.”
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Mother’s Age ‘affects Autism Risk’
Women who delay pregnancy are more likely to have a child with autism, the Daily Mail reported. It said researchers have found that a woman of 40 has a 50% higher risk than a woman in her late 20s.
This research followed nearly 5 million children from birth and compared the parental characteristics of those who developed autism with those who did not. It found that older mothers were associated with an increased risk of the child later developing autism.
This was generally well-conducted research, but it only considered a few of the many possible factors that might affect the risk of autism. The cause of autism is not known, but genetics, brain development, allergies, immunity and the environment have all been suggested as possibilities.
Older women who want to have children should not be overly concerned by these findings. Their risk of having a child with autism remains small. Overall, only about 0.2% of the children in this study developed autism. A systematic review of these results and other similar studies may be able to determine whether the evidence supports a link between parental age and autism risk.
What Other Experts Think
The finding of increased risk in younger grandparents is novel, said Thomas Frazier, PhD, a professor of psychology at John Carroll University in Ohio and the former chief science and program officer for Autism Speaks.
It could mean that young grandparents convey some risk to their children that magnify, or at least complement, increased risk in the parent, Frazier told Healthline.
For example, if young grandparents also have less money, and this results in poorer nutrition, that could impact the biology of the parent. These biological impacts might then be magnified in older parents, he added.
Frazier says the study suggests there may be some environmental factors that affect the child. But he says the results need to be repeated and show whether the grandparent effect remains after controlling for the advanced parental age.
For research, it suggests we should try to understand the factors, genetic and possibly epigenetic, that get transmitted from parent to child, and how this seems to result in greater problems for the child in older parents, he explained. Are there ways we can reduce these impacts? Supplementation? Exercise? Other parent health factors?
Bottom line? We need to study this more, Frazier said.
Healthline asked Lynn for her reaction to the study.
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Not Taking Enough Folic Acid
Too much folic acid has been linked to causing autism, and not taking enough has been linked to other birth defects. The right amount of folic acid, especially around the time of conception, can greatly reduce the risk of a child developing autism. When taking folic acid while pregnant, to prevent increasing the chance of autism, it is the mother’s job to diligently monitor her levels of folic acid, by regularly seeing her doctor. Folic acid helps lessen the effects of pesticide exposure in the fetus, thus greatly reducing the risk of the child developing autism. For a pregnant woman, speaking to her doctor will be the best route to find out just how much folic acid is right for her and her fetus.
Study Confirms Link Between Older Maternal Age And Autism
Maternal age and autism are both on the rise–but only a small fraction of the increasing incidence can be explained by the trend toward later childbearing
It is common knowledge: As women get older, pregnancy becomes a riskier enterprise. Advanced maternal age is linked to a number of developmental disorders in children, such as Down’s syndrome. Now, a study has confirmed that older mothers are more likely to give birth to a child with autism, too.
The authors of the epidemiological study, published February 8 in Autism Research, examined the parental age of more than 12,000 children with autism and nearly five million “control” children between 1990 and 1999, all living in California. The researchers found that mothers over 40 had a 51 percent higher risk of having a child with autism than mothers 25 to 29, and a 77 percent higher risk than mothers under 25.
Other contributors to the increasing incidence of autism remain unclear. “We’re doing a lot of research into environmental risk factors,” Shelton says, describing ongoing research into possible nutritional factors and toxic chemical exposure during labor and development. It is possible that the increased risk associated with maternal age might reflect the mother’s longer cumulative exposure to unknown environmental factors, the authors report.
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Where Did The Story Come From
The research was carried out in the US by Janie F Shelton and colleagues from the University of California. The study was funded by grants from the National Institute of Environmental Health Sciences, the US Environmental Protection Agency, and the UC Davis School of Medicine and Office of Graduate Studies. The paper was published in the peer-reviewed medical journal Autism Research .
The news stories have generally reflected the findings of this paper accurately.
Traits In Mothers May Signal Gene Variants For Autism
by Taylor White / 16 October 2020
Autistic childrens traits track more with subtle, autism-like behaviors in their mothers than with those in their fathers, according to a new study1.
In particular, autistic children whose mothers have problems with pragmatic language communicating in social settings tend to have especially prominent social-communication difficulties themselves, the study shows. Whats more, those mothers also have many common genetic variants linked to autism. These common variants are thought to account for as much as half of autisms genetic basis.
The findings suggest that the same genetic factors that contribute to autism also underlie a collection of mild traits known as the broad autism phenotype. The presence of these traits may be a sign that a woman carries a genetic predisposition to autism.
I was really excited to see that features of broad autism phenotype, and especially language-related features, seem to be really important in understanding how genetic liability is expressed and really linked to molecular genetic variation, says co-lead investigator Molly Losh, director of the Neurodevelopmental Disabilities Lab at Northwestern University in Evanston, Illinois.
It shows that autism traits and expression of the conditions genetics roots may differ for mothers and fathers, says co-lead investigator Lea Davis, assistant professor of genetic medicine at Vanderbilt University in Nashville, Tennessee.
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Offspring Of Mothers With The Ptenwt/m3m4 Genotype Show Increased Asd
To interrogate the impact of maternal genetics on the incidence and severity of an ASD-like phenotype in the offspring, PtenWT/m3m4 females were bred to PtenWT/WT males or PtenWT/WT females were bred to PtenWT/m3m4 males to compare pups of a heterozygous mutant mother vs. pups of a homozygous wildtype mother . Average litter sizes from PtenWT/WT females X PtenWT/m3m4 males and PtenWT/m3m4 females X PtenWT/WT males were similar. In contrast, a significant decrease in litter size was observed when PtenWT/m3m4 females X PtenWT/m3m4 males, most likely due to 100% loss of Ptenm3m4/m3m4 homozygous mutant fetuses in-utero around E15.5. For this reason, PtenWT/m3m4 female X PtenWT/m3m4 male crosses were not compared further in the study for the maternal inflammatory state, due to additional inflammatory insults from resorption of homozygous mutant fetuses in-utero. The number of PtenWT/WT and PtenWT/m3m4 pups born were as expected per Mendelian ratios indicating no genotype preference or in-utero mortality differences between the two maternal or offspring genotypes . However, postnatally, PtenWT/m3m4 mothers lost more pups between P0 and P8. Litters of Momsm3m4 had postnatal mortality of 2024% of their pups in 5667% of all litters compared to only 4% pup death in 29% of litters from MomWT .
Fig. 1: Pups of PtenWT/m3m4 mothers have higher postnatal mortality, macrocephaly, and ASD-like behavior compared to PtenWT/WT mothers.
Do Certain Medications Cause Autism
The only medications known to increase the risk of ASD are used for epilepsy or as a muscle relaxer in anesthesia. For example, the anti-seizure drug valproate increases the risk of autism from 1.9% to 4.4%.
Previous research suggested antidepressant and antipsychotic medications may increase risk, but the latest studies disprove this connection. Its the severity of underlying mental health issues, not the medications, that increases the risk of ASD.
Please try not to worry if you have a mental health issue. The overwhelming majority of mothers even with severe mental health diagnosis do not have babies with ASD.
What is important now is stopping any drug or alcohol use that may be associated and talking to your doctor about medication, which may be harmful to the fetus even though it doesnt increase the risk of ASD.
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Endogenous Opiate Precursor Theory
In 1979, Jaak Panksepp proposed a connection between autism and opiates, noting that injections of minute quantities of opiates in young laboratory animals induce symptoms similar to those observed among autistic children. The possibility of a relationship between autism and the consumption of gluten and casein was first articulated by Kalle Reichelt in 1991.
Opiate theory hypothesizes that autism is the result of a metabolic disorder in which opioid peptides gliadorphin and casomorphin, produced through metabolism of gluten and casein , pass through an abnormally permeable intestinal wall and then proceed to exert an effect on neurotransmission through binding with opioid receptors. It has been postulated that the resulting excess of opioids affects brain maturation, and causes autistic symptoms, including behavioural difficulties, attention problems, and alterations in communicative capacity and social and cognitive functioning.