RELN and autism: The coexpression of common genetic variants associated with risk of preterm birth and those associated with very high risk of autism [27], such as chromodomain-helicase-DNA-binding protein 8 (CHD8), reelin (RELN), Synaptic Ras GTPase-activating protein 1 (SYNGAP1), and T-box family transcription factor 1 (TBR1), could explain higher risk of autism and/or autistic symptoms in premature infants (Fig. 1b, c); independent expression of high-risk autism gene variants alone could explain why not all autistic children are born prematurely.