GEMMA project will recruit a cohort of 600 infants (age 0-6 months) who have a family history of autism (i.e. siblings of patients with autism) along with their sibling in the condition. At enrolment, prenatal information (maternal risk factors, maternal infections, etc.) will be collected.

Three children recruitment centers are involved to allow a global sampling based on their geographical coverage:

• National University Of Ireland Galway (NUIG) www.nuigalway.ie
  Irish Centre for Autism and Neurodevelopment Research (ICAN), Ireland geraldine.leader@nuigalway.ie
• ASL Salerno, Italy reclutamento@gemma-project.eu
• The General Hospital Corporation, MGH, Boston, U.S.A., www.partners.org, mghgemma@mgh.harvard.edu

Participants will be evaluated as a child with autism or child without autism based on the Autism Diagnostic Observation Schedule (ADOS) coupled with Toddler Module, a new diagnostic method. The ADOS Toddler evaluation will be conducted every 6 months (starting 12 months of age) and used as the primary. Participants will also be evaluated as children with gastrointestinal (GI) symptoms or children without GI symptoms based on the existence of chronic irregular GI disorders that has not been present since birth.

All infants will be sampled every 6 months until 36 months for blood, urine, stools and saliva. The samples placed in a biobank so that changes over time of specific gut microbiota, metabolites , gut barrier function, immune, genetic and epigenetic profiles can be assessed over time. At each sampling time point, clinical and dietary data will be recorded.

The study provides:

Clinical observational study [N=600 infants who have a family history of autism (i.e. siblings of patients with autism)] to prospectively follow from birth a cohort so that the composition and function of the microbiome can be compared in the same subject before and after the possible onset of the condition

Inclusion/exclusion criteria:
Inclusion: healthy neonates or infants, first degree relatives of ASD individuals (at least one parent or sibling affected by ASD), younger than 6 months/26 weeks at study entry, have never received solid food (elementary formula feeding is permitted).
Exclusion: neonates with significant health issues (e.g.chronic disease, single gene disorder, FragileX, major brain malformation) that require specific surgical or continuous medical treatments, infants older than 6 months/26 weeks, infants who have been introduced to solid food, severe GI problems requiring immediate treatment (life-threatening), severely underweight /malnourished children, dietary restriction in the previous 3 months, tube feeding,drugs since birth that may affect the biomarkers being assessed, for example antibiotics within one month prior to enrolment or antibiotics used as a continuous course for ≥28 days prior to enrolment.

Clinical interventional study (N=40-60 ASD and ASD-GI children) to test the assumption that pro/pre/symbiotics on specific targeted population stratified by validated biomarkers can attenuate the expression of ASD and co-morbidities.

Inclusion/exclusion criteria:
Inclusion: Infants over 18 months of age who have completed the observational study, developed clinical signs 
and symptoms of ASD whose parents will permit the intervention in this study to be the sole dietary/oral 
therapy during the study period.
Exclusion: Infants who did not complete the observational study, infants who started any other therapeutic 
oral/medical/dietary intervention for ASD, any of the exclusion criteria mentioned in the observational study