Childhood Disorder Rett Syndrome Recreated in Adult Animal Model

An International Rett Syndrome Foundation-funded study published online on June 2, 2011, in the journal Science has shown that the childhood disorder Rett syndrome (RTT), can be reestablished in adult animals by "switching off" a critical disease-causing gene in healthy adult animals. The gene was "switched off" in adult mice by use of a sophisticated genetic trick, resulting in the appearance of behaviors typically seen in RTT. The leading author Christopher McGraw, MD/PhD student, carried out the study in the laboratory of Dr. Huda Zoghbi, a renowned neuroscientist based at Baylor College of Medicine, and director of the Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital in Houston, Texas. In 1999, Dr. Zoghbi's laboratory made a central discovery, identifying the causative link between mutations in the gene methyl-CpG-binding protein 2 (MeCP2) and RTT. This work led to other studies showing that MeCP2 protein is critical for the proper functioning of nerve cells during development and into adulthood. In 2007, a further study conducted by Dr. Adrian Bird, at Edinburgh University in the UK, showed the neurological symptoms of RTT can be reversed by reactivating MeCP2 in an adult mouse where the disease is already established. This work provided a critical proof of concept that symptoms of the disorder may be reversible in humans; however, to date it was not known whether the early developmental period was important in establishing the course of the disease. This new study argues that early expression of the gene does not protect against the development of symptoms if the disease gene is later inactivated. Commenting on the study, Dr.