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Mutations in Genes That Modify DNA Packaging Result in Facioscapulohumeral Muscular Dystrophy (FSHD)
A recent finding by medical geneticists sheds new light on how facioscapulohumeral muscular dystrophy develops and how it might be treated. More commonly known as FSHD, the devastating disease affects both men and women. FSHD is usually an inherited genetic disorder, yet sometimes appears spontaneously via new mutations in individuals with no family history of the condition. "People with the condition experience progressive muscle weakness and about 1 in 5 require wheelchair assistance by age 40," said Dr. Daniel G. Miller, University of Washington (UW) associate professor of pediatrics in the Division of Genetic Medicine. Dr. Miller and his worldwide collaborators study the molecular events leading to symptoms of FSHD in the hopes of designing therapies to prevent the emergence of symptoms or reduce their severity. In the November 11, 2012 online issue of Nature Genetics, Dr. Miller and Dr. Silvere M. van der Maarel of Leiden University in The Netherlands, along with an international team, report their latest findings on the role of epigenetic modifications in causing the disease. In Seattle, Dr. Stephen Tapscott of the Fred Hutchinson Cancer Research Center was also a major contributor to the project. He is a UW professor of neurology and a researcher at the UW Center for Human Development and Disability. Epigenetics refers to mechanisms that influence how the genome is regulated and how, where, and when genes act -- all without altering the underlying DNA sequence. The flexibility of DNA packaging – its wrapping, which can be tightened and loosened, and its chemical tags – is one of the epigenetic forces on the genome. This packaging is called the chromatin structure and is one way specialized cells such as those in our muscles allow groups of genes to be shut off, or be available for expression.