Credit: Ulf Sirborn The causes of the serious muscle disease ALS still remain unknown. Now, researchers at Karolinska Institutet and KTH Royal Institute of Technology, among others, have examined a type of cell in the brain blood vessels that could explain the unpredictable disease origins and dynamics. The results indicate a hitherto unknown connection between the nervous and vascular systems. The study, which is published in Nature Medicine, has potential implications for earlier diagnoses and future treatments. ALS (amyotrophic lateral sclerosis) is a neurodegenerative disease of the motor neurons that eventually causes muscular atrophy, paralysis and death. There is currently no cure.