1 Department of Neurology (MGS, JG), Hospital Universitario Miguel Servet; Department of Clinical Biochemistry (SI), Hospital Universitario Miguel Servet, Section of Genetics, Zaragoza; NIMGenetics (SA), Madrid; Department of Internal Medicine (REBA), Hospital Universitario Miguel Servet, Zaragoza; Department of Neurology (JB), Hospital Universitario Marqués de Valdecilla, Santander, Spain.