Why some kids are born autistic

A new study has claimed that autism genes activate during fetal brain development.

Scientists at the University of California, San Diego School of Medicine have found that mutations that cause autism in children are connected to a pathway that regulates brain development.

Lead researcher Lilia Iakoucheva, PhD said that the surprising thing they immediately observed while studying a set of well-known autism mutations called copy number variants or CNVs, was that different CNVs seemed to be turned on in different developmental period.

Specifically, the scientists noted that one CNV located in a region of the genome known as 16p11.2, contained genes active during the late mid-fetal period. Ultimately, they identified a network of genes that showed a similar pattern of activation including KCTD13 within 16p11.2 and CUL3, a gene from a different chromosome that is also mutated in children with autism.

Iakoucheva said that they realized that the proteins encoded by the genes, form a complex that regulates the levels of a third protein, RhoA. Rho proteins play critical roles in neuronal migration and brain morphogenesis at early stages of brain development.

Interestingly, the RhoA pathway has recently been implicated in a rare form of autism called Timothy syndrome, which is caused by the mutation in a completely different gene.

Iakoucheva and colleagues are planning to test RhoA pathway inhibitors using a stem cell model of autism.

The research is published in Neuron.