Treatment of FUS-Related ALS With Betamethasone - The TRANSLATE Study

By doing this study the investigator hopes to learn more about a potential cause of amyotrophic lateral sclerosis (ALS) called "oxidative stress". Oxidative stress is essentially an imbalance between the production of certain chemicals in the body called "free radicals" and the ability of the body to counteract or detoxify their harmful effects through neutralization by antioxidants. It is thought that factors such as environmental exposure (chemicals and lead), diet, smoking,alcohol consumption, physical activity and psychological stress cause oxidative stress to occur inside the body. By doing this study, the investigator hopes to learn whether the FDA-approved steroid medication called Betamethasone will restore overall antioxidant activity fALS patients with mutations in the Fused in Sarcoma gene (FUS gene). Participants who agree to take part in this research study, agree to the following responsibilities: * Attend all scheduled visits * Notify the study doctor of any illnesses, unexpected or troublesome side effects, or any other medical problems that occur during the study * Be completely honest with their answers to all questions * Check with the study doctor before taking any new medications, whether prescribed or "over the counter," even vitamins and herbal supplements.