Gene mutations linked to older dads28th August 2012
Having an older father may put some people at greater risk of some disorders, particularly those involving the brain, according to a recent genetic study.
A company based in Iceland found in recent research that the number of genetic mutations carried by children was directly linked to the age of their father when they were conceived.
Writing in the journal Nature, the research team at Decode Genetics concluded that the age of a child's father counts for more, genetically speaking, than does the age of the mother.
Society has previously focused largely on the role of the mother in heritable disorders, but research lead author Kari Stefansson said that the health of the father's sperm is crucial in deciding the likelihood of disorders like schizophrenia and possibly autism.
Stefansson said that, with the exception of Down's Syndrome, disorders like schizophrenia and autism are influenced by the age of the father and not the mother.
For the purposes of the research, Decode Genetics sequenced the genomes of 78 families and examined the data for a possible correlation between the number of alterations to the DNA found in the child, and the age of the father.
They found that a 20-year-old father is likely to pass on approximately 25 mutations to a child, while a man fathering a child at 40 passes on about 65. They concluded that for every year that a man waits to father children, they could be developing two more mutations to hand on to a child.
Genetic mutations have previously been showed to increase with age, and sperm are more vulnerable to mutated DNA, because a man continues to produce sperm over the course of a lifetime, whereas a woman is born with all her eggs already in place.
The researchers said that 97% of all mutations passed on to children are from older fathers, and that they had been surprised by the strength of the association, especially as no other factors were involved.
Stefansson said that the average age of fathers has been rising sharply in industrialised countries since 1970, a period which has also seen an increase in autism.
He said that it was likely that the rise in autism was at least in part accounted for by the rise in average ages of fathers.
However, he said that older men thinking of fathering children should not worry too much, as the overall occurrence of disorders was very low, meaning that even a doubled risk was still low.
The brain depends more upon genes for its development and normal functioning than other systems of the body, so genetic mutations are more closely linked with neurological disorders than with other conditions.
University of Michigan professor Alexey Kondrashov wrote in an accompanying commentary that young men might want to consider freezing their sperm for use later in life, if the current study was validated by further research.
However, genetic mutations have a role to play in the evolution and adaptation of the species, and so older fathers may also be contributing to that process.
According to a spokesman for the National Autistic Society many younger fathers also have children with autism, and more research wills be needed into the genetic aspects of autism before reliable conclusions can be drawn.
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Title: Gene mutations linked to older dads
Author: Luisetta Mudie
Article Id: 22562
Date Added: 28th Aug 2012