Myelin protein zero Arg36Gly mutation with very late onset and rapidly progressive painful neuropathy.

Mutations in myelin protein zero (MPZ) protein result in a wide spectrum of peripheral neuropathies, from congenital hypomyelinating to late onset sensory and motor axonal forms. In some patients, neuropathic pain can be a prominent symptom, making the diagnosis challenging mainly in those with other risk factors for neuropathy. We describe a 77-year-old woman with impaired glucose tolerance presenting with rapidly progressive axonal neuropathy leading to excruciating pain and severe weakness of lower limbs within 2 years from the onset. Her son abruptly complained of similar painful symptoms at the age of 47 years. Molecular analysis revealed a novel heterozygous missense mutation (c.106A>G) in MPZ exon 2, causing the substitution of arginine-36 with glycine in the extracellular domain. Our observation suggests that MPZ-related neuropathy should be considered in the diagnostic work up of patients with painful axonal neuropathy even presenting with rapid progression and at a very late age of onset.