Molecular analysis of three cases with hereditary motor and sensory neuropathy with myelin outfolding.

We describe three patients affected by a congenital motor and sensory neuropathy with excessive myelin outfoldings (MOs) [15]. Clinical and electrophysiological features supported the diagnosis of hereditary motor and sensory neuropathy. We previously reported a genetic study on these three patients, which failed to demonstrate either the duplication in chromosome 17p11.2 or the mutations at exons 1 and 2 of the peripheral myelin protein gene (PMP-22) and suggested an autosomal recessive (AR) inheritance. In this study we described the absence of the most common mutations, which characterized other forms of hereditary motor and sensory neuropathy (HMSN). In particular the absence of molecular changes in the PMP-22 gene definitively sets HMSN with MOs apart from the more common CMT1A, hereditary neuropathy with liability to pressure palsies (HNPP) and progressive sensory-motor polyneuropathy with tomaculous changes at sural nerve biopsy.