HARLINGEN - Tortillas made with contaminated corn may have caused a rash of newborns with missing or rudimentary brains in the Rio Grande Valley in the 1990s, new data suggest. According to the February issue of the journal Environmental Health Perspectives, researchers now have human studies linking a toxin in corn mold called fumonisin with babies' neural tube defects. Scientists have been searching more than a decade for answers to the surge of anencephalic babies - babies born without brains or with underdeveloped brains - in the Rio Grande Valley from 1990-92. There were six such cases in six weeks...