Screening of the 17p11.2--p12 region in a large cohort of patients with Charcot-Marie-Tooth (CMT) disease or hereditary neuropathy with liability to pressure palsies (HNPP)

Abstract

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.