[1] Gothenburg Univ, Dept Pediat, S-41124 Gothenburg, Sweden
[2] Gothenburg Univ, Dept Pathol, S-41124 Gothenburg, Sweden
[3] Malmo Univ Hosp, Dept Paediat, Malmo, Sweden
[4] Univ Lund, Dept Mol & Cell Biol, Lund, Sweden
[5] Karolinska Hosp, Dept Neurol, S-10401 Stockholm, Sweden