How Genetic Defects Cause Microcephaly (VIDEO) Columbia University Irving Medical Center This video is under embargo. Please login to access this video. Caption Youtube link: https://www.youtube.com/watch?v=X9ysnvUrU6g In a very severe, genetic form of microcephaly, stem cells in the brain fail to divide, according to a new study that may provide important clues to understanding how the Zika virus affects the developing brain. Credit Columbia University Medical Center Usage Restrictions No restrictions License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.