ASD	Autism Spectrum Disorder
GI	gastrointestinal
MGB	microbiota gut–brain
CNS	central nervous system
FMT	fecal microbiota transplantation
FGIDs	functional gastrointestinal disorders
MTT	Microbiota Transfer Therapy
HPA	hypothalamic–pituitary–adrenal
ENS	enteric nervous system
CRH	corticotropin-releasing hormone
TNF-α	tumor necrosis factor-alpha
SCFAs	short-chain fatty acids
IL	interleukin
BBB	blood–brain barrier
GABA	gamma-aminobutyric acid
LPS	lipopolysaccharide
GOSs	galacto-oligosaccharides
MAC	microbiota-accessible carbohydrates
GFCF	gluten-free, casein-free
SCD	Specific Carbohydrate Diet