Duchenne muscular dystrophy (DMD) is a fatal, x-linked disease that affects 1 in every 3,500 live born males. DMD is caused by the loss of the protein dystrophin due to genetic mutation. Dystrophin is abundant at the cell membrane of muscle cells, where its function is to stabilize the plasma membrane against contraction-induced membrane damage by binding to cytoskeletal f-actin filaments and the transmembrane protein dystroglycan. A small percentage of DMD cases are caused by missense mutations where the change in a single amino acid can cause severe disease. This disease can be caused by dystrophin not being able to bind its intracellular partners or by misfolding of the dystrophin protein, which can lead to degradation or insoluble aggregates. I investigated this aggregation as a possible mechanism for the pathogenesis of DMD missense mutations. I specifically worked with five missense mutations: K18N, L54R, L172H, Y231N, and T279A. These particular mutations are located in the actin-binding domain on the N-terminus of dystrophin. Of the fifteen known missense mutations in DMD patients, nine of them are found in this region. The missense mutations in this area can cause disease in one of two ways. The mutations can cause the protein to fold improperly, which leads to the aggregation and the loss of its localization to the membrane. The mutations can also render the protein unable to bind actin properly, despite normal folding and transportation of the protein to the membrane. For this project, I compared the levels of insoluble protein for various types of mutant dystrophin to the levels of wild type (WT) dystrophin (data provided by D.M. Henderson) to determine whether the mutations cause misfolding. I hypothesized that disease-causing missense mutations in the N-terminal actin binding domain of dystrophin cause misfolding and increase the level of insoluble dystrophin in vivo.