GDAP1 and Charcot-Marie-Tooth disease: Mutations in the GDAP1 gene show phenotypic and Mendelian heterogeneity in CMT patients and lead to several forms of CMT including recessive demyelinating (CMT4A)3, recessive axonal (AR-CMT2K)4, recessive with intermediate clinical features (CMTRIA)5 and a dominant inheritance pattern and axonal features (CMT2K)6, 7.