Above Genetics: Lessons from Cerebral Development in Autism
Emily L. Williams and Manuel F. Casanova. Translational Neuroscience, Volume 2, Number 2, 106-120, DOI: 10.2478/s13380-011-0016-3
While a distinct minicolumnar physical characteristic seems to be an underlying factor in a significant portion of cases of autism, attention is paid not only to genetics but to environmental factors which may lead to development of the conditions. Here we discuss the indivisible role the molecular environment plays in cellular function, particularly the pivotal position which the transcription factor and adhesion molecule, β-catenin, occupies in cellular growth. In addition, the learning environment is not only integral to postnatal plasticity, but the prenatal environment plays a vital role during corticogenesis (organization of the cells during development), neuritogenesis (development of nerve tissues), and synaptogenesis (development of cell communication junctions). To illustrate these points in the case of autism, we review important findings in genetics studies and known environmental factors (valproic acid, estrogen, immune system, ultrasound) which may predispose towards the minicolumnar and connectivity patterns seen in the conditions, showing how one-gene mutational syndromes and exposure to certain central nervous system teratogens (agents which disturb fetal development) may ultimately lead to comparable phenotypes. This in turn may shed greater light on how environment and complex genetics combine to give rise to a heterogenetic group of conditions such as autism.
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