Acamprosate in C9orf72 Hexanucleotide Repeat Expansion Amyotrophic Lateral Sclerosis (ACALS)

Background: Amyotrophic lateral sclerosis (ALS) is a disorder that damages nerve cells in the brain and spinal cord. It can cause muscle weakness, paralysis, and loss of movement. The symptoms grow worse over time. Half of all people with ALS live only 3 to 5 years after diagnosis. Current drug treatments can slow the progress of the disease, but they cannot stop or reverse it. Objective: To test a study drug (acamprosate) in people with ALS with a mutation in the C9orf72 gene. Eligibility: People aged 18 years and older with ALS. They must have a mutation in the C9orf72 gene. Design: Participants will have 13 visits over 32 weeks. Five visits will be at the clinic, and 8 visits will be by phone. Participants will have a baseline visit of up to 3 days. They will have a physical exam with blood tests. They will have imaging scans and tests of their breathing ability. Their memory, thinking, and behavior will be assessed. They will have a neurologic exam to check their reflexes, strength, balance, eyes, and coordination. They will complete questionnaires about their daily life. They will have a lumbar puncture to collect fluid from the area around the spinal cord. Acamprosate is a pill taken by mouth. Participants will take 2 pills by mouth 3 times a day with meals for 24 weeks. They will record their doses and any missed doses in a diary. Baseline tests will be repeated during follow-up clinic visits. These tests may be spread out over 3 days. During phone visits, participants will talk about how they are doing. They will review their diary with researchers.