There’s hope for families of the estimated 21.7 million people around the globe who suffer from autism — scientists have found a link between the GABA neurotransmitter and autism symptoms that could lead to breakthroughs in treatments and diagnosis methods. But there may be many more families who don’t even realize their child has autism, because symptoms early on can be hard to spot.

The study is good news for everyone, and indicate that we understand much more about the neurodevelopomental disorder than we have in years past. The study could allow us to spot autism even earlier, but as it stands now, it’s still tough to tell at least at the very early stages if a child has autism — meaning those with newborns will have to watch out for some early signs.

People with autism tend to have difficulty with social interaction and communication, and they can exhibit restricted and repetitive behavior. Signs usually show up the first two years of a child’s life, but they tend to come on gradually.

“Individuals with autism are known to have detail-oriented visual perception–exhibiting remarkable attention to small details in the sensory environment and difficulty filtering out or suppressing irrelevant sensory information,” Caroline Robertson of MIT’s McGovern Institute for Brain Research said in a statement. “It’s long been thought this might have something to do with inhibition in the brain, and our findings lend support to this notion.”

Parents should look for the following signs of autism in their children, based on guidelines from the organization Autism Speaks:

– No big smiles or joyful expressions by six months of age.
– No sharing of sounds or expressions by nine months.
– No babbling by their first birthday.
– No words at the 16-month mark.
– No meaningful phrases by their 2nd birthday.
– Loss of speech at any age.

If you suspect your child may be autistic, visit a doctor for an evaluation.