[1] Mayo Clin, Dept Neurol, Coll Med, Rochester, MN 55905 USA
[2] Mayo Clin, Dept Med Genet, Coll Med, Rochester, MN 55905 USA
[3] Mayo Clin, Dept Lab Med & Pathol, Coll Med, Rochester, MN 55905 USA
[4] Mayo Clin, Dept Bioinformat & Stat, Coll Med, Rochester, MN 55905 USA