Scottie Cramp is an episodic disorder of Scottish Terriers that produces a dramatic increase in muscle tone with excitement or exercise. The cause of the disease is unknown, although pharmacologic studies suggest that abnormal signaling between neurons plays a role. The disease is hereditary and is transmitted by an autosomal recessive trait. As a result, carriers of the disease are clinically normal, and the trait has become widespread within the breed. A genetic test for the disease would allow selective breeding to eliminate the disease. In previous work we have collected DNA from affected dogs (grant 1362-A), and performed a genome-wide association analysis using SNP data (grant 0143) and have identified two regions significantly associated with Scottie Cramp. In this project we will sequence these region using deep sequencing techniques. We will use the resulting data to identify mutations associated with the Cramp phenotype and test these mutations for sensitivity and specificity of predicting affected, carrier and clear status.