A new study has found that fragile X syndrome, the most common genetic cause of mental retardation and autism, occurs because of a mechanism that shuts off the gene associated with the disease. While researchers have known that the excess repetition of a particular segment of the genetic code is the reason behind the disease, they were unsure why a large number of these repetitions sets the disease process in motion. Using stem cells from donated human embryos that tested positive for fragile X syndrome, the study’s reasearchers found that early on in fetal development, messenger RNA begins sticking itself onto the DNA of the fragile X syndrome gene, thus making it inactive and unable to produce a protein crucial to the transmission of signals between brain cells. Read more in Science.
D Colak et al., Science, 2014. DOI: 10.1126/science.1245831