Sperm defects in older men
Dr Kirsty Horsey
Progress Educational Trust
10 August 2003
New research has added to the growing body of evidence that children fathered by older men may face some physical health problems. A British and Swedish research team based at Oxford University, UK, has found that an inherited condition called Apert syndrome is more likely to develop in the children of older men. Apert syndrome causes children to be born with distorted skulls and often to have webbed fingers or toes.
In Apert syndrome, mutations in a gene called FGFR2 are passed from the father (who is unaffected) to the child. The mutations 'are associated with increased paternal age', say the researchers, who have published their findings in the journal Science. The majority of the one in 700,000 children born with the condition in the UK are born to older fathers, which suggested that the gene mutation that causes the condition occurs more frequently in men as they age. However, the researchers found no increased incidence of the FGFR2 mutation. Instead, they found that the mutation itself was very infrequent, but, when it did occur, it had a great effect on the way sperm was produced. Professor Andrew Wilkie said that this was similar to the effect of cancer, 'with rogue cells multiplying and producing sperm with the mutated gene'.
However, the researchers also found that the gene mutation, although it causes Apert syndrome in children if a sperm carrying it fertilises an agg, is actually beneficial to the sperm itself, as it helps it to survive longer in the testes.
In 2001, a study showed that older fathers produce children with a much higher risk of developing schizophrenia: this too was thought to be caused by mutations in sperm that increased with paternal age. Then, researchers pointed to 'strong evidence' that men, like women, have a 'biological clock' when it comes to having children, challenging commonly held beliefs that while older women risk having babies with birth defects, men can safely father children whatever their age.
© Copyright Progress Educational Trust
Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.
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