We excluded from our study children with a suspected genetic, metabolic, or neurodegenerative disorder (including 10 children with initial diagnosis of CIDP and final diagnosis of leukodystrophy, concurring CMT1a, CMTx, and mitochondrial neurogastrointestinal encephalomyopathy syndrome, and mutation of actin α1 gene (ACTA1). This evidence concerns the gene PMP22 and leukodystrophy.