Inclusion Criteria - Patient with ALS, ALS-FTD or Similar Neurodegenerative Disease:  Clinical diagnosis of possible, laboratory-supported probable, probable or definite ALS according to modified eL Escorial criteria, suspected ALS according to original el Escorial criteria, or diagnosis of a similar neurodegenerative disorder. Willing to provide consent, or assent, if physically unable to consent owing to disease-related muscle weakness.  Inclusion Criteria - Spouse/Domestic Partner of Patients with ALS/ALS-FTD and Similar Neurodegenerative Disorder or Subject with Family History of ALS, ALS-FTD or Similar Neurodegenerative Disease:  No personal history of ALS, ALS-FTD or other motor neuron disease. Subjects with family history of ALS, ALS-FTD the affected family member needs to be a first, second, or third degree blood relative. Willing to provide consent.  Exclusion Criteria - Subject with ALS/ALS-FTD or Similar Neurodegenerative Disease:  History of medical disorder that leaves in question whether neurological signs and symptoms potentially related to a neurodegenerative disease may be caused by another unrelated disorder. Limited mental capacity rendering the subject unable to comply with lumbar puncture or standard phlebotomy procedures. For lumbar puncture, an increased risk of bleeding complications or allergy to local anesthetic administered or skin antiseptic used for lumbar puncture.  Exclusion Criteria - Spouse/Domestic Partner of Patients with ALS/ALS-FTD and Similar Neurodegenerative Disorder or Subject with Family History of ALS, ALS-FTD or Similar Neurodegenerative Disease:  Limited mental capacity rendering the subject unable to comply with lumbar puncture or standard phlebotomy procedures. For lumbar puncture, an increased risk of bleeding complications or allergy to local anesthetic administered or skin antiseptic used for lumbar puncture.