2013) and whole genome studies (Gonzaga-Jauregui et al. 2012) may be useful in identifying new genetic etiologies for CMT phenotypes, but our study supports that targeted sequencing is likely to yield interpretable genetic results in at least 18.5% of CMT patients. The results of our study in a population in over 17,000 individuals support the initial genetic testing of four genes (PMP22, GJB1, MPZ, and MFN2) followed by an evaluation of rarer genetic causes in the diagnostic evaluation of CMT. This evidence concerns the gene MPZ and Charcot-Marie-Tooth disease.