[1] Natl Specialized Childrens Hosp Okhmatdyt, Kiev, Ukraine
[2] Natl Univ PL Shupik, Dept Med & Lab Genet, Kiev, Ukraine
[3] Univ Oxford, MDUK Oxford Neuromuscular Ctr, Oxford OX3 9DU, England
[4] Univ Oxford, NIHR Oxford Biomed Res Ctr, Oxford OX3 9DU, England
[5] Univ Hosp Liege, Neuromuscular Reference Ctr, Dept Paediat, Liege, Belgium
[6] Univ La Citadelle, Liege, Belgium