Father's age may increase risk of autism in children
A father's age before conception may affect the risk of autism in children, and a new scientific study offers new explanations for how this might happen, through biological changes in sperm.
For years, studies have shown that children born to older fathers have a slightly higher risk of being diagnosed with autism spectrum disorders. However, the biological mechanism behind this has remained unclear.
According to a new study in the field of epigenetics, as men age, small but measurable changes occur in the way some genes in sperm function, especially near genes linked to early brain development and autism, reported. TechnologyNetworks.
Epigenetics relates to chemical marks that influence the behavior of genes without changing the DNA itself.
One of these marks is called DNA methylation. These marks are very important in the early stages of life because they help guide the development of the organism.
In sperm, these epigenetic marks are reset during cell formation, which makes them particularly sensitive to age and environmental factors.
The study authors noted in the report that most previous studies on sperm and age "were not designed to clearly identify genes associated with heredity or children's health," making interpretation of the results more difficult.
The new study analyzed the sperm of 63 healthy, non-smoking men aged 18 to 35. The researchers measured changes in about 450 DNA spots and looked at how these changes correlated with age.
The results showed that at more than 14 DNA sites, methylation levels changed with age, usually gradually decreasing. Although these changes were small, they were stable and often located near areas of DNA that control early brain development.
Some of these areas are linked to genes that, in previous studies, have been involved in autism and in communication between nerve cells.
The researchers stressed that these findings do not mean that an older father will definitely have a child with autism.
"The changes measured in DNA methylation were small, but even very small epigenetic perturbations in sperm may have significance at the population level, especially if men continue to father children later and later," the study report states.
They have clarified that these changes do not predict autism in specific individuals, but may easily contribute to increased risk on a broader scale.
The study also has limitations as it does not include men over 35, even though the risk of autism increases more after this age.
Also, there is no data from children, so it cannot be directly proven that these changes are passed on to the next generation or truly affect development.
However, researchers see this work as an important starting point.
