Our lab uses mouse models to identify the molecular pathways underlying degenerative motor neuron diseases and degenerative muscle diseases that affect people. One interest relates to spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease). We cloned the gene for neuromuscular degeneration to create a mouse model for a lethal infantile form of SMA known as spinal muscular atrophy with respiratory distress and identified a modifier gene that decreases disease severity in the mice. Our studies on degenerative muscle diseases similar to muscular dystrophy in humans, have led us to identify an important mutation to the muscle-specific titin gene. This mouse strain is a novel model of progressive muscular dystrophy and may also be a model for human tibial muscular dystrophy and limb-girdle muscular dystrophy type 2J. We also identified the mutation for a new form of rostrocaudal muscular dystrophy that affects skeletal muscle tissues in a unusual front-to-back progression.