Molecular genetic tools are key for research aimed at understanding the mechanisms underlying brain development and neurological disorders. In our laboratory we use two approaches to get a handle on genes mediating key neuronal functions and brain health. The first approach involves studying human patients that suffer from an inherited neurological disease in order to identify the responsible gene. We use genetic mapping studies to localize and identify the gene, and eventually we study the function of the disease-causing gene and the consequences of the mutations in mouse models. The other approach involves the identification of genes essential for normal neuronal function and brain development in lower organisms (such as the fruit fly) and studying their mammalian homologues. We have used both approaches to study two genes, SCA1 and Math1. The use of mouse models has proven key in providing insight about the roles of these genes in balance, hearing, and breathing, and about ways to test potential therapies for neurodegenerative disorders.