Bilir B, Yapici Z, Yalcinkaya C, Baris I, Carvalho CMB, Bartnik M, Ozes B, Eraksoy M, Lupski JR, Battaloglu E. High frequency of GJA12/GJC2 mutations in Turkish patients with Pelizaeus-Merzbacher disease. Clin Genet 2013: 83: 66-72. (C) John Wiley & Sons A/S. Published by Blackwell Publishing Ltd, 2012 Pelizaeus-Merzbacher disease is an early onset dysmyelinating leukodystrophy. About 80% of PMD cases have been associated with duplications and mutations of the proteolipid protein 1 (PLP1) gene. Pelizaeus-Merzbacher-like disease is a genetically heterogeneous autosomal recessive disease and rarely caused by mutations in gap junction protein alpha 12 (GJA12/GJC2) gene. The molecular basis of the disease was investigated in a cohort of 19 Turkish families. This study identified novel chromosomal rearrangements proximal and distal to, and exclusive of the PLP1 gene, showed equal frequencies of PLP1 and GJA12/GJC2 mutations at least in our cohort, and suggested further genetic heterogeneity.