NEW YORK – Chinese scientists have created monkeys with a version of autism that could eventually help in the cure for this complex spectrum of brain disorders that affects millions of children worldwide. Autism has been identified in approximately 1 in 68 children in the U.S., and its characteristics are only now becoming better known.
Although the Chinese scientists’ breakthrough is significant, it also raises some practical and ethical questions. Rett Syndrome is a rare genetic disorder that causes many of the symptoms of autism. Ninety percent of patients with this disorder have a mutation in a gene called MeCP2. Duplicate copies of this gene produce the kind of autism known as MeCP2 duplication syndrome. Although scientists had previously created this kind of autism in mice, their brains, unlike the brains of monkeys, are much simpler than humans’ and don’t show many of the developmental and behavioral problems that humans manifest. Now, for the first time, Chinese scientists have created monkeys whose DNA has been genetically altered to make them develop a type of autism similar to that found in humans.
The creation of these “transgenic” monkeys, reported in the journal Nature, offers a good model for studying and understanding human brain disorders such as autism.
Zilong Qiu, a neuroscientist at the Shanghai Institutes for Biological Sciences, said his team has created more than dozen monkeys with a specific genetic error. Children with a similar genetic mutation manifest a rare syndrome whose symptoms include mental retardation, repetitive speech and difficulty communicating.
The transgenic monkeys showed some behaviors typical of autistic disorders, such as repetitive motions while walking in circles, less interaction with other monkeys and increased anxiety.
Zilong Qiu recently said that once they find the brain circuits responsible for the altered behavior in monkeys, scientists can start using noninvasive brain stimulation techniques or even gene therapy, where a missing or defective gene is replaced. Zilong also said scientists in his group will now try to reverse the symptoms they created by eliminating the genetic error in live animals, which in itself is a very complex endeavor.
The study with transgenic monkeys is particularly valuable because it demonstrates that genetically modified monkeys can be a very good model for studying autism and related disorders.
Some autism experts, although encouraged by these new developments, have cautioned that although the transgenic monkeys showed similar symptoms to autistic disorders, not all of the symptoms were similar to humans with autistic disorders. In addition, creating monkeys with psychiatric disorders raises complex ethical questions, particularly among animal welfare activists.
Despite these constraints, however, the experiments carried out so far by Chinese scientists open new possibilities for understanding and treating a most complex and widespread kind of disorder, one that has caused enormous suffering to children and their families worldwide.
Cesar Chelala is an international public health consultant.