Within the last decade, numerous methods have been applied to detect the most common mutation in patients affected with Charcot-Marie-Tooth (CMT) disease, i.e. submicroscopic duplication in the 17p11.2-p12 region. In 1993, another neuropathy ? known as hereditary neuropathy with liability to pressure palsies (HNPP) -has been shown to be caused by a 17p11.2-p12 deletion. Historically, Southern blot analysis was the first approach to identify CMT1A duplication or HNPP deletion. This time- and labor-consuming method requires prior selection of DNA samples. In fact, only CMT patients affected with the demyelinating form of CMT1 have been screened for CMT1A duplication. After the 17p11.2-p12 duplication was identified in the CMT1 families, subsequent studies revealed additional axonal features in the patients harboring the 17p11.2-p12 duplication. Thus it seems reasonable to test all patients affected with CMT for the presence of the 17p11.2-p12 duplication. To evaluate the utility of real-time polymerase chain reaction (Q-PCR) and restriction fragment length polymorphism PCR (RFLP-PCR), we screened a large group of 179 families with the diagnosis of CMT/HNPP for the presence of the 17p11.2-p12 duplication/deletion. Due to a high frequency of CMT1A duplication in familial cases of CMT, we propose (in contrast to the previous studies) to perform Q-PCR analysis in all patients diagnosed with CMT.