A team of researchers has suggested that paternal sperm may hold clues to autism.
Johns Hopkins researchers found that DNA from the sperm of men whose children had early signs of autism shows distinct patterns of regulatory tags that could contribute to the condition.
In this study, investigators looked for possible causes for the condition not in genes themselves, but in the "epigenetic tags" that help regulate genes' activity. Co-lead investigator Daniele Fallin said that if epigenetic changes are being passed from fathers to their kids, they should be able to detect them in sperm.
Researchers Andrew Feinberg, Fallin and their team assessed the epigenetic tags on DNA from sperm from 44 dads. The study enrolls pregnant mothers who already have a child with autism and collects information and biological samples from these mothers, the new baby's father and the babies themselves after birth. Early in the pregnancy, a sperm sample was collected from fathers enrolled in the study. One year after the child was born, he or she was assessed for early signs of autism using the Autism Observation Scale for Infants (AOSI).
The researchers collected DNA from each sperm sample and looked for epigenetic tags at 450,000 different positions throughout the genome. They then compared the likelihood of a tag being in a particular site with the AOSI scores of each child. They found 193 different sites where the presence or absence of a tag was statistically related to the AOSI scores.
When they looked at which genes were near the identified sites, they found that many of them were close to genes involved in developmental processes, especially neural development.
Of particular interest was that four of the 10 sites most strongly linked to the AOSI scores were located near genes linked to Prader-Willi syndrome, a genetic disorder that shares some behavioral symptoms with autism. Several of the altered epigenetic patterns were also found in the brains of individuals with autism, giving credence to the idea that they might be related to autism.
The study appears in the International Journal of Epidemiology.
