Anyone who has spent even a little time with an autistic boy or girl soon becomes familiar with the behaviors that set these children apart: lack of eye contact, trouble verbalizing, overreacting or underreacting to activities around them, difficulty in expressing their feelings and in understanding the emotions of others. But how do parents and doctors know if a baby, who is too immature to be gauged on any of these traits, has autism? Early diagnosis has proved difficult.
Inability to detect autism until a child is two or three years old is a terrific disadvantage. It "eliminates a valuable window of treatment opportunity, when the brain is undergoing tremendous development," says David G. Amaral, professor of neurobiology and psychiatry at the University of California, Davis.
Amaral and researchers at other institutions, however, are closing in on techniques that could detect autism in babies as young as six months and perhaps even at birth. The results of these new tests--some controversial--are expanding the understanding of autism and raising hopes for much earlier, specialized care that could improve a toddler's chances for a more normal life as a child, teenager and adult.
A Simple Blood Test?
Autism affects a wide variety of developmental traits. Some young autistic children speak; others do not. Some possess almost average intellectual abilities; others are severely limited. As they grow older, certain autistic individuals display incredible talents in very specific domains. Known as savants, they can memorize an entire book in hours or solve complex math problems faster than people using a calculator. The 1988 movie Rain Man dramatized these abilities in a character named Raymond Babbitt, played by Dustin Hoffman, who won an Oscar for the role. Babbitt was based on a real savant named Kim Peek, who continues to astonish today.
It is no wonder, then, that determining whether a young child is autistic is fraught with uncertainty. Diagnosis typically involves rating a child's behaviors against a set of standards. The exercise usually is not conclusive until at least the child's second birthday. That is why scientists are seeking an earlier and more accurate test, and they are getting closer. At the International Meeting for Autism Research in Boston in May 2005, Amaral presented the initial results of a landmark study. His team compared blood samples from 70 autistic children ages four to six with samples from 35 randomly selected subjects in the same age group. The autistic children had a higher proportion of two basic immune system cells known as B cells and T cells. Significant differences also became apparent in more than 100 proteins and small molecules commonly found in the bloodstream.
After further analysis, the team decided that the pilot study results were strong enough to launch a full-scale investigation. In March 2006 Amaral announced that U.C. Davis's Medical Investigation of Neurodevelopmental Disorders Institute, which he heads, was starting the Autism Phenome Project. It will enroll 900 children with autism plus 450 more who have developmental delays and 450 who are developing normally. Researchers will analyze the children's blood proteins, immune systems, brain structures and functions, genetics and environmental exposures. The participants will be two to four years old at the outset and will be followed for several years. Amaral thinks it is probable that telltale genetic markers will be found. But it will take several years before the project is finished and analyzed and longer still before a routine test for autism could be administered at a doctor's office.
If the blood profiles prove to be reliable, the screening could occur just after a baby is born. But the validity of detection that early in life requires more scrutiny. Amaral says there is a growing view among experts that not all individuals who have autism are "doomed at birth," as has been commonly believed. "It may be that some children have a vulnerability, such as a genetic abnormality," he says, "and that something they encounter after being born, perhaps in their environment, triggers the disorder."