"The data further demonstrate the potential of ZFN-mediated genome editing to achieve unique biological outcomes which may have significant medical and therapeutic value," stated Philip Gregory, D. Phil., Sangamo's vice president, research and chief scientific officer. "In these studies, Sangamo's ZFN technology was used to insert a 17Kb DNA sequence containing a copy of the XIST gene into a pre-defined location in a particular chromosome. This is a substantially larger DNA sequence than is commonly used for genome editing and demonstrates the precision and efficiency of the ZFN-mediated process."The paper entitled " Translating Dosage Compensation to Trisomy 21" described the highly specific and efficient ZFN-mediated insertion of copy of a large gene called XIST, into chromosome 21 in cultured iPSCs derived from DS patients. XIST encodes an RNA which normally functions in early development to shut down one of the two X chromosomes present in females, a process called dosage compensation. The XIST gene product functions by coating the chromosome from which it is expressed resulting in the silencing of the majority of the genes on that chromosome. In the study described by Jiang et al. in Nature, the silencing was observed on the extra, or third, copy of chromosome 21 in cells modified using the ZFNs. By comparing unmodified cells with cells in which the extra chromosome had been silenced by ZFN-mediate XIST addition, the authors showed that XIST helps correct defects in cell growth and neural differentiation found in DS-derived cells. The strategy can be used to help define the cellular and molecular changes underpinning DS and other trisomy disorders, as well as provide a model to study human chromosome inactivation. About Sangamo Sangamo BioSciences, Inc. is focused on research and development of novel DNA-binding proteins for therapeutic gene regulation and genome editing. The Company has ongoing Phase 2 and Phase 1 /2 clinical trials to evaluate the safety and efficacy of a novel ZFP Therapeutic ® for the treatment of HIV/AIDS. Sangamo's other therapeutic programs are focused on monogenic diseases, including hemophilia, Huntington's disease and hemoglobinopathies such as beta-thalassemia and sickle cell anemia. Sangamo's core competencies enable the engineering of a class of DNA-binding proteins known as zinc finger DNA-binding proteins (ZFPs). Engineering of ZFPs that recognize a specific DNA sequence enables the creation of sequence-specific ZFP Nucleases (ZFNs) for gene modification and ZFP transcription factors (ZFP TFs) that can control gene expression and, consequently, cell function. Sangamo has entered into a strategic collaboration with Shire AG to develop therapeutics for hemophilia, Huntington's disease and other monogenic diseases and has established strategic partnerships with companies in non-therapeutic applications of its technology including Dow AgroSciences and Sigma-Aldrich Corporation. For more information about Sangamo, visit the company's website at www.sangamo.com. ZFP Therapeutic ® is a registered trademark of Sangamo BioSciences, Inc. This press release may contain forward-looking statements based on Sangamo's current expectations. These forward-looking statements include, without limitation, the potential of ZFNs to advance the studies and understanding of Down syndrome and human chromosome inactivation , research and development of novel ZFP TFs and ZFNs and therapeutic applications of Sangamo's ZFP technology platform. Actual results may differ materially from these forward-looking statements due to a number of factors, including uncertainties relating to the initiation and completion of stages of our clinical trials, whether the clinical trials will validate and support the tolerability and efficacy of ZFNs, technological challenges, Sangamo's ability to develop commercially viable products and technological developments by our competitors. For a more detailed discussion of these and other risks, please see Sangamo's SEC filings, including the risk factors described in its Annual Report on Form 10-K and its most recent Quarterly Report on Form 10-Q. Sangamo assumes no obligation to update the forward-looking information contained in this press release. SOURCE Sangamo BioSciences, Inc.