The sperm of old mice has an unusual epigenome, the profile of chemical modifications to the underlying DNA code, according to a poster presented Saturday at the 2012 Society for Neuroscience annual meeting in New Orleans. The findings suggest an explanation for the so-called paternal age effect in autism.
Spectrum: Autism Research News
Tag: rare variants
Mutations in AFF2, a gene located on the X chromosome, are about five times as common in men with autism as in controls, according to a study published 10 July in Human Molecular Genetics.
With every passing year, men are increasingly likely to transmit new mutations to their children, according to the largest study yet of the so-called paternal age effect, published yesterday in Nature. The findings could help explain why older men are more likely to have a child with autism or schizophrenia than are younger men, the researchers say.
To find the pathogenic mutations in complex disorders such as autism, researchers may need to conduct sophisticated analyses of the genetic functions that are disrupted, says geneticist Aravinda Chakravarti.
Rare variants make up the vast majority of human genetic variation, according to two independent papers published in May in Science. That means that genetic studies of complex diseases such as autism are likely to require tens of thousands of participants.
Researchers have found deletions and duplications of a small piece of chromosome 2 in individuals with autism, developmental delay, epilepsy or attention deficit hyperactivity disorder.
By screening for recessive mutations, which are present in both copies of a gene, researchers have identified four autism candidates that may be involved in neuronal signaling, according to a study published 12 April in PLoS Genetics.