Molecular and Clinical Genetics -- Engrailed2 and Cerebellar Development in the Pathogenesis of Autism Spectrum Disorders -- Teratogenic Alleles in Autism and Other Neurodevelopmental Disorders -- Cholesterol Deficit in Autism: Insights from Smith-Lemli-Opitz Syndrome -- Autism in Genetic Intellectual Disability -- Neurotransmitters and Cell Signaling -- Serotonin Dysfunction in Autism -- Excitotoxicity in Autism -- Prenatal ?2-Adrenergic Receptor Signaling and Autism: -- Endocrinology, Growth, and Metabolism -- A Role for Fetal Testosterone in Human Sex Differences -- Interaction between Genetic Vulnerability and Neurosteroids in Purkinje cells as a Possible Neurobiological Mechanism in Autism Spectrum Disorders -- Insulin-Like Growth Factors -- Oxidative Stress and the Metabolic Pathology of Autism -- Immunology, Maternal-Fetal Interaction, and Neuroinflammation -- The Immune System in Autism -- Maternal Immune Activation, Cytokines and Autism -- Maternal Antibodies and the Placental-Fetal IgG Transfer Theory -- Can Neuroinflammation Influence the Development of Autism Spectrum Disorders? -- Neuroanatomy and Neural networks -- The Significance of Minicolumnar Size Variability in Autism -- Imaging Evidence for Pathological Brain Development in Autism Spectrum Disorders -- Information Processing, Neural Connectivity, and Neuronal Organization -- Environmental Mechanisms and Models -- Evidence for Environmental Susceptibility in Autism -- An Expanding Spectrum of Autism Models -- Erratum.