Children of older men have more gene abnormalities: study
2012 08 23

By Mariette le Roux | AFP

Do older fathers doom their children to genetic disease? This is the question raised by a new study that says older men produce more gene mutations in the children they sire, boosting their risk of schizophrenia and autism and possibly other diseases.

A father’s age is by far the biggest factor determining the rate of new, uninherited genetic mutations in his offspring, according to a paper published Wednesday in the journal Nature.

From a man’s peak reproductive years in adolescence, the rate of new or "de novo" gene mutations triggered at conception in his children rises by about two per year, the study found.

The rate doubles every 16 years, meaning that the baby of a 36-year-old father would have twice as many new mutations than that of a 20-year-old.

"The age of the father is the most important factor to determine the number of new mutations that happen when a child is conceived," study co-author Kari Stefansson from Iceland’s DeCODE genetics company told AFP.

Though de novo mutations are not necessarily harmful, it can take only one change in a key gene to cause some types of disease -- and the more mutations the higher the risk.

The results from what is claimed to be the biggest-ever study of its kind suggest that disproportionate attention has been paid to the age at which women give birth.

"We have in a very unjust manner been pointing the finger at the old mother when we should have been careful when it comes to the old father. It is clearly dangerous to have an old father," said Stefansson.

Maternal age is linked to Down’s syndrome and other chromosomal diseases that develop through a process that is different to the type of genetic mutation described in this study.

The mutations in the Nature report are caused by cell division during processes like sperm production.

Stefansson and a team in Iceland, Denmark and Britain sequenced the genomes of 78 parent-child trios, as well as hundreds of control subjects, looking for variants in the sequence of a child’s genetic code that did not exist in the parents.

They found that the rate of increase in de novo mutations could be ascribed to the tune of 97.1 percent, "maybe entirely", to the age of the father -- an outcome that "surprised" the researchers.

The remaining 2.9 percent was ascribed to environmental factors and other random influences, Stefansson said, adding there was "no connection" between the mother and age-related increase in the rate of mutations.

The average newborn today has about 60 new small-scale mutations -- ranging from 25 in the child of a 20-year-old man to 65 in that of a 40-year-old, Alexey Kondrashov of the University of Michigan’s department of ecology and evolutionary biology wrote in an analysis of the study.

The number of de novo mutations ascribed to the mother always remains roughly 15, regardless of her age.

Previous research has shown a link between de novo mutations and autism and schizophrenia, and also a statistical link between the diseases and paternal age.

"Our contention is that a part of the increase in the diagnosis of autism that is being made these days is accounted for by increase in the age of the father," said Stefansson.

And he added further research is likely to show a similar link to other genetic illnesses, especially diseases of the brain.

In a comment also carried by Nature, Kondrashov said the study suggested a rethink of the advisable age to have children. It might be a "wise individual decision" for young men to cold-store their sperm for later use.

The age of new fathers in the Western world has been climbing in recent decades, and the number of first-time dads over 40 is growing. Official statistics show that in Iceland, the average age of fathers at conception rose from 27.9 in 1980 to 33 in 2011.

Contrary to de novo mutations which occur during cell division, inherited gene mutations are transferred at an equal rate by the father and mother, are more common and thus more commonly responsible for disease.

Scientists believe that both inherited and new mutations are responsible for diseases like autism and schizophrenia, but have not worked out the ratio of blame.

On the positive side, de novo gene mutations are a necessary element of human evolution, allowing us to adapt to our changing environment.


Article from: news.yahoo.com




Related Articles
Grandin on The Autism Surge
Study: Autism Linked to Industrial Food, Environment
Can Autism Really Be Diagnosed in Minutes?
Brain Imaging Could Detect Autism Risk in Infants as Young as 6 Months
’Parent Training’ May Help Kids With Autism Behave Better
Autism Gastro Problems May Be Linked to Gut Bacteria
The Mystery of Akhenaten: Genetics or Aesthetics?
Sunburns damage your genetic code?
Gattaca - Visit to the local geneticist
Getting fetus’ genetic makeup from mother blood test


Latest News from our Front Page

The Aeon of Horus is Ending and the Elites are Nervous as their Icons are Dying
2014 04 18
I predict there is going to be a huge resurgence of interest in European indigenous spiritual traditions from Norse to Celtic/Gaelic to Slavic and so on. Millions of Europeans are going to realise that we are the victims of Christianity and New Age garbage. Their bastardised Kabbalah, the psychic force used by Crowley and the elites to cement his Aeon ...
Easter - Christian or Pagan?
2014 04 18
From: truthbeknown.com Contrary to popular belief, Easter does not represent the "historical" crucifixion and resurrection of Jesus Christ. In reality, the gospel tale reflects the annual "crossification" of the sun through the vernal equinox (Spring), at which time the sun is "resurrected," as the day begins to become longer than the night. Rather than being a "Christian" holiday, Easter celebrations date back ...
Man-Made Blood Might Be Used in Transfusions by 2016
2014 04 18
Researchers in the U.K. have created the first man-made red blood cells of high enough quality to be introduced into the human body The premise of the HBO show and book series True Blood revolves around a technological breakthrough: scientists figure out how to synthesize artificial human blood, which, as an ample new source of non-human food, allows vampires to "come ...
The Trials of the Cherokee Were Reflected In Their Skulls
2014 04 18
Researchers from North Carolina State University and the University of Tennessee have found that environmental stressors – from the Trail of Tears to the Civil War – led to significant changes in the shape of skulls in the eastern and western bands of the Cherokee people. The findings highlight the role of environmental factors in shaping our physical characteristics. ...
Our Fears May Be Shaped by Ancestral Trauma
2014 04 18
Last December, an unsettling Nature Neuroscience study found that mice who were taught to associate the smell of cherry blossoms with pain produced offspring who feared the smell of cherry blossoms, even if they had never been exposed to it before. We knew that the process was epigenetic—that it was not hard-wired in the permanent genetic structure of the mouse—but ...
More News »