Children of older fathers are known to be more at risk for diseases including schizophrenia and autism. Now, a new scientific look at the genes passed down within families may have pinpointed a reason why.

The study, reported today in the journal Nature, found that older fathers transmit more new DNA variations to their children than younger dads, with each added year of age resulting in an average of 2 extra new mutations. The genetic changes occur in men as they age because of environmental factors, such as radiation, or through mistakes that occur in cell division.

The research led by scientists at Reykjavik, Iceland-based deCode Genetics Inc., is the first to quantify the number of new, or de novo, mutations that fathers hand along by age to their children. The findings may suggest that dads-to-be should consider collecting their sperm at a young age and storing it for later use, according to Alexey Kondrashov, a professor of evolutionary biology at the University of Michigan in Ann Arbor.

“If the paternal-age effect on the de novo mutation rate does lead to substantially impaired health in the children of older fathers, then collecting the sperm of young adult men and cold-storing it for later use could be a wise individual decision,” Kondrashov wrote in an accompanying editorial that called for further study on the issue.

Mental processes may be most affected, leading to illnesses such as schizophrenia, because more genes express themselves in the human brain than elsewhere.

Autism Increase

The de novo findings suggest it may be “reasonable to assume that the ongoing increase in the incidence and prevalence of autism in many human populations could be due, at least in part, to the accumulation of mutations resulting from relaxed selection and a higher average paternal age -- and not only to better recognition of cases,” Kondrashov said.

The US Centers for Disease Control and Prevention in March reported that one in 88 children in the US had autism or a related disorder in 2008, the latest period for which data was available. That was a 23 percent rise from 2006, the agency’s researchers reported, saying it was unclear how much of the increase was due to increased awareness of the disease.

Genes are the blueprints for making all the proteins needed by the human body to grow, develop and work properly. DeCode Genetics’ group looked at the DNA shared by 78 groups of Icelandic mothers, fathers, and children.

A 20-year-old father transmits on average 25 new mutations to his child while a 40-year-old transmits 65, the study found. Mothers always transmit about 15 new mutations, regardless of their age, according to the accompanying editorial.

Men Worse

Men probably contribute more mutations because sperm have to divide many more times than eggs, which don’t actively split when women are of reproductive age, according to Kondashov.

“The only important thing when it came to explaining the mutations was the age of the father,” said study author Kari Stefansson, who is also the chief executive officer of deCode Genetics. “There’s very little else to be accounted for. That’s a stunning observation.”

Most de novo mutations are neutral, and all mutations in the genome were once de novo, Stefansson said by telephone. Once scientists determine the importance of de novo mutations relative to heredity mutations in autism, it will be easy to see how much contribution a father’s age has to the child’s health. That work hasn’t yet been done, he said.

http://bostonglobe.com/lifestyle/health-...story.html

Why do they keep calling Autism a disease?

I'm a little suspicious, considering there is a well-documented increased likelihood for a maternal egg to experience non-disjunction in older women.  The overwhelming majority of people with down syndrome get the extra chromosome from their mother, and not from their father--something on the order of 90%.  So a study that finds no increase in the amount of mutations in women over age surprises me.

Also consider that men with autistic traits may tend to get into relationships much later in life, often because it takes us longer to feel comfortable in our own skin. I didn't get into any relationship until I was 36. Became a father at 40. Does that mean I was more likely to pass on genes because I was older.... Or because I lacked the social skills to connect with potential mates at a younger age.

Thanks for the genes, Dad!  
Although one thing is puzzling: I'm the eldest in my family, and the only one of we four girls to be autistic, the other three are totally NT.  And quite a large proportion of autistic children I've taught over the years have also been the eldest, with subsequent younger siblings being NT.  Do the father's genes change back after the first Autistic kid?  
Alison

I'm wondering the samething with my father..... I honestly don't know if its because I was born when he was oh lets see..... 31 years old?

Yeah, my older brother (by about four years) is a textbook NT, so I was wondering about that too. Although the study does kind of explain why autism seems to be more prevalent in developed countries than in developing countries, since men often wait longer to have children.

It fits here: my youngest son; my father was the youngest; and his youngest uncle, all on the Spectrum(at least I think so). It doesn't fit with me: I'm the oldest.

They come up with batshi* crazy studies like this every other week. One I remember linked large breasts to breast cancer.

This isn't the daily mail either...

Unfortunetley, due to this. It isn't laughable as the majority of people believe it...

I really wish they'd stop referring to us as a disease, too.

Why do they keep calling Autism a disease?

Because they're idiots.

I'm the oldest person in my immediate family and my father(who I suspect is an aspie) is the second oldest in his family. I personally believe that Autism(the higher functioning varient) is a naturally occuring gene variation. Social Society won't accept that, though, due to their inability to cope with a mind that differs so from the majority. This is the same reason "mass-schooling" fails to actually educate all of the people. Lower-Functioning is a varient of the higher-functioning types, but the functional place in society is even further removed socially. I am also of the belief that Autism is (to some extent) genetic.

This post was last modified: 08-24-2012 08:46 AM by AspieGrrl.

All mutations are a natural part of variation.  If you were paying attention when they were discussing darwin in class, you may have heard that the environment deterimines the value of a mutation.  

Instead, sadly, people seem more prepared to accept eugenics-themed lies totally unchallenged.  White moths are superior to black moths, even when the trees are black and the moths have no camouflage

This post was last modified: 08-24-2012 10:20 AM by Lang.

LOL, BAD AspieGrrl!  I shall speak to your mum.  Why didn't you pay attention in class to that nice Mr darwin? Then you'd know that e = an equal and opposite react...er, no hold on, that wasn't it...um... oh yeah, a rolling moth gathers no trees ... er, wait, wait, I'll get it, I know this ... oh yeah, black moths and white moths should mate so we can have lots of little grey moths.  So there!
Alison

This post was last modified: 08-24-2012 10:45 AM by Alison.

So when they say older...my father was 20 when he had me and I was 27 when i had him Neither is "older" both me and my son were Autistic.
Boom another conspiracy theory blown out of the water.

Double post.

This post was last modified: 08-24-2012 02:08 PM by Bloke.