Autism is defined by behavioral patterns and delays in language development, but chronic gastrointestinal (GI) problems are also seen, like abdominal pain, diarrhea, constipation, esophagitis, and gaseousness. The central hypothesis of this proposal is that altered handling of intracellular calcium ion by GI nerve and muscle causes some of these GI disorders. To study these disorders, we will use a genetically altered mouse that exhibits the rare disorder of Timothy Syndrome (TS). Individuals with TS have a genetic mutation in a cell membrane calcium ion channel, known as Cav1.2. Strikingly, over 80% of patients carrying this mutation have also been diagnosed with autism. No other human mutation shows this high degree of correlation. We hypothesize that this mutation in TS mice will cause nerve and muscle cells to be overloaded with calcium ion. Specifically, we will examine intestinal smooth muscle in TS mice to determine if intracellular calcium ion overload alters its ability to propel food. We will also determine if nerves of the intestine abnormally regulate the absorption processes. Next, we will use molecular biological techniques to identify mutant Cav1.2 channels in intestinal smooth muscle and nerves of TS mice and electro-physiological techniques to determine the mechanisms that lead to altered function of these channels. Study of this unique mouse will provide key insights into the cellular basis of autism and its relationship to GI disorders and will provide a model for testing new therapies.