This document provides information about autism spectrum disorder, including signs, prevalence rates, potential causes, and research efforts. Some key points: - Signs of autism can begin appearing between ages 2-3 and include lack of eye contact, difficulties socializing and communicating, and repetitive behaviors. - Around 1 in 68 children in the US has been diagnosed with autism spectrum disorder. Boys are 4.5 times more likely to be diagnosed than girls. - Genetic and environmental factors may increase risk, but vaccines are not a cause. Ongoing research is exploring genetic and environmental risk factors. - Autism spectrum disorder covers a range of conditions involving difficulties with social skills and communication as well as repetitive behaviors

1. Although autism spectrum disorder can
be detected at 18 months or younger, the
most obvious signs begin at ages 2 to 3.
Here are some things to look for:
• Lack of joyful expressions (such as
smiles) by 6 months
• No exchange of sounds or facial
expressions by 9 months
• No babbling by 12 months
• No words by 16 months
• Tendency to repeat words, phrases and/
or behaviors
• Resistance/trouble adapting to change in
daily routine
• Difference in manner of learning
• Hyporeactivity to sensory input (smells,
sights, sounds, tastes, etc.)
• Avoiding eye contact
• Desire to be alone
• Failure to understand others’ feelings
• Lack of interest in socializing
• Reluctance to be held/cuddled
• Difficulty communicating needs
• Difficulty expressing or discussing his/
her own feelings
• Displays lack of awareness of voices but
responds to other sounds
• Displays difficulty talking to and/or
playing with others
• Regression in babbling, vocabulary or
social skills at any age
• Lack of problem-solving ability
• Failure to develop/understand
relationships
1 IN 68 children has been identified
with an autism spectrum disorder
As early as age 2, a diagnosis by an
experienced professional can be
considered very reliable
An estimated 1 in 42 boys in the U.S. is
diagnosed with autism spectrum disorder,
compared with 1 in 189 girls. That is 4.5
times more boys than girls.
More than 3 MILLION PEOPLE in
the U.S. are affected
Autism spectrum disorder occurs in all
racial, ethnic and socioeconomic groups
African-American and Hispanic children
are less likely than white children to be
identified as having an autism spectrum
disorder.
There is no medical test to diagnose these
disorders — diagnoses are based on
doctors observing behavior.
Sources: CDC and Autism Speaks
Scientists in the past five years have
identified a number of rare gene
mutations associated with autism
spectrum disorder. It tends to occur more
often in those with Fragile X syndrome
or tuberous sclerosis, but there are likely
many causes and many different factors
both genetic and environmental, according
to the Centers for Disease Control and
Prevention (CDC). Nongenetic risk factors
include:
• The age of the parents at conception
(children born to older parents are at
greater risk)
• An illness during pregnancy
• Birth difficulties, especially if they involve
oxygen deprivation to the baby’s brain
• Certain prescription drugs (valproic acid
and thalidomide), when taken during
pregnancy
These factors seem to slightly increase
risk, but ONLY when genes indicate a
predisposition to autism. The CDC notes
that many studies show there is no
relationship between vaccines — believed
by many parents to be a cause — and
autism spectrum disorder.
The role of the immune system is being
targeted in ongoing research. The CDC
is working on the Study to Explore Early
Development, investigating genetic,
environmental, pregnancy and behavioral
factors as risk factors.
ABOUT AUTISM SPECTRUM DISORDER
THE FACTS
Autism awareness has spiked among parents, teachers and health care providers in the past few years,
as we learn more about prevalence rates and begin to identify potential causes and risk factors.
LEARN ABOUT AUTISM AND THE COMMON SIGNS WITH THIS FACT SHEET
SOME TELLTALE SIGNS AUTISM FACTS AND FIGURES CAUSES
WHAT IS AUTISM?
“Autism” and “autism spectrum disorder” are terms for several brain development disorders characterized by socialization
and communication difficulties, and limited and repetitive behavioral patterns. Autism spectrum disorder includes Asperger
syndrome, autistic disorder, childhood disintegrative disorder and pervasive developmental disorder-not otherwise specified
(PDD-NOS). These conditions once were considered distinct, but now all are diagnosed as autism spectrum disorder.
Individuals can be at various points on the autism “spectrum.” About 40 percent have average or better intellectual abilities.
Many are gifted artistically, musically or academically. Others have significant disabilities and cannot live independently. About
a third are nonverbal. There is no cure for autism spectrum disorder, but early intervention can aid a child’s development.