Professor Massimo Castagnola of Institute of Biochemistry and Clinical Biochemistry, Catholic University, Rome, Italy, with his team compared the salivadefine samples of 27 kids, including seven girls and 20 boys, with autism spectrum disorder or ASD; 12 with autism diagnosis, 1 with Asperger and 14 with pervasive developmental disorders (PDD-NOS), which did not afflict other 23 kids of the same age.

They focused on the naturally occurring salivary peptides, which build blocks of protein, in the saliva samples.

The study, which has appeared in the current issue of the Journal of Proteome Research, found that two third of the subjects with ASD had at least one salivary peptide that differed from kids without the disorder.

However, researchers could not track precisely, if autism was the reason for those differences, if so, why those differences did not appear in all the autistic kids. They are still examining the peptides, to further help identifying “a considerable subgroup" of individuals with ASD and the peptide differences might trace back to the central nervous system (CNS).

The saliva tests is not available at the moment for use and more research is needed in the field to show, if really there is a link between the peptides and autism, scientists noted.

According to the U.S. Centers for Disease Control and Prevention (CDC), autism and related disorders such as Asperger's syndrome affect an estimated one out of every 150 children in United Staes alone.

A past study had found that babies diagnosed with autism, usually show atypical ways of playing with toys such as spinning, repetitively rotating and looking at the toys out of the corners of their eyes, in as early as twelve months.