Case report Immune-mediated inflammatory polyneuropathy overlapping Charcot-Marie-Tooth 1B Marcio Luiz Escorcio-Bezerra ⇑,1 , Wladimir Bocca Vieira Rezende Pinto, Denis Bernardi Bichuetti, Paulo Victor Sgobbi Souza, Richard Mady Nunes, Luiz Henrique Libardi Silva, Karlla Danielle Ferreira Lima, Gilberto Mastrocola Manzano, Acary Souza Bulle Oliveira, Alex Machado Baeta Department of Neurology, Universidade Federal de São Paulo, SP, Brazil article info Article history: Received 5 January 2020 Accepted 9 March 2020 Available online xxxx Keywords: Hereditary neuropathy CIDP Chronic inflammatory demyelinating polyneuropathy MPZ gene Myelin protein zero P0 abstract Charcot Marie Tooth (CMT) due to myelin protein zero (MPZ) mutations, may cause a wide variation of phenotypes, depending on the localization of the mutation within the gene. Among the most common phenotypes are: an infantile onset disease with extremely slow nerve conduction velocities (CMT1B) and an adult onset phenotype with nerve velocities in the axonal range (CMT2I). We reported a patient with CMT1B (MPZ p.Ser63del mutation) which developed an overlapping immune mediated polyradicu- loneuropathy with recurrent episodes of quadriparesis and cranial nerve involvement. We observed reversible conduction block on serial neurophysiologic studies, non-uniform demyelination and good clinical response to prednisone and cyclophosphamide, as evidenced by objective functional recovery. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)-like characteristics have not yet been described associated with a MPZ p.Ser63del mutation. This description adds evidence indicating that a defective structural myelin protein may predispose peripheral nerves to immune attacks. Ó 2020 Elsevier Ltd. All rights reserved. 1. Introduction Charcot-Marie-Tooth disease (CMT) is a subgroup of inherited neuropathies in which the peripheral nerve involvement is the sole or predominant feature [1]. There have been some recent reports, of the association of CMT and Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), an immune-mediated neuropathy. It is not yet completely understood whether these co-occurrences are coincidental or not, but most of the reports involve the PMP22 and X-linked CMT genes, which are key elements to the formation of compact myelin, suggesting that defective myelination may pos- sibly trigger inflammation [2–4]. Herein, we present a patient with demyelinating CMT due to mutation in the MPZ (Myelin Protein Zero) gene, who developed a severe recurrent neuropathy with clinical and neurophysiological features of CIDP and a marked response to immunotherapy. 2. Case report A 31-year-old woman had delayed motor milestones, started walking during childhood and never achieved running skills. She had the presumed diagnosis of inherited neuropathy. She was an only child and family history disclosed a deceased father with pes cavus and difficulty walking. When she was 17 years old, about a week after a chickenpox infection, she developed tingling in feet and hands, with ascending flaccid areflexic quadriparesis, which evolved over a period of 6–10 weeks. The episode was treated as an overlapping chronic inflammatory neuropathy with corticos- teroids. There was clinical functional recovery in the following months. She remained clinically stable during the following years. During this plateau period, she had mild distal weakness in the lower limbs, steppage gait, mild distal hypoesthesia, pes cavus, glo- bal absent tendon reflexes and mild bilateral global ophthalmo- paresis (Fig. 1). At 28 years old there was a marked worsening of signs and symptoms, as she developed ascending quadriparesis and hand and feet numbness over four weeks, and then progressive dyspha- gia and respiratory distress. Examination disclosed severe flaccid quadriparesis, absent tendon reflexes, worsening of ophthalmo- paresis and facial diplegia. Muscle strength was 1/5 in distal upper limbs (UL) and in lower limbs (LL); and 2/5 in proximal UL. Tendon https://doi.org/10.1016/j.jocn.2020.03.014 0967-5868/Ó 2020 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Neurology, Escola Paulista de Medic- ina, Universidade Federal São Paulo, Rua Pedro de Toledo, 650, 04039-002 São Paulo, SP, Brazil. E-mail address: marciobzrra@gmail.com (M.L. Escorcio-Bezerra). 1 0000-0002-2417-1061. Journal of Clinical Neuroscience xxx (xxxx) xxx Contents lists available at ScienceDirect Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn Please cite this article as: M. L. Escorcio-Bezerra, W. B. V. R. Pinto, D. B. Bichuetti et al., Immune-mediated inflammatory polyneuropathy overlapping Char- cot-Marie-Tooth 1B, Journal of Clinical Neuroscience, https://doi.org/10.1016/j.jocn.2020.03.014