S68 Abstracts / Neuromuscular Disorders 29 (2019) S37–S208 independent variable to capture how the mOBFRS score changed over time. Since study initiation, 150 ALS subjects have been enrolled and 66 subjects have completed the study. The mOBFRS score was negatively correlated with the BRS total score, ALSFRS-R total score, and ALSFRS-R bulbar sub-score at all three visits (p<0.0001). Subject’s mOBFRS score changed by 2.53 points from baseline to month 6 (p<0.0001), showing increased sensitivity compared to the decrease in the BRS score from 1.00 points from baseline to month 6 (p<0.021). The ALSFRS-R swallow ability question was compared to the mOBFRS timed swallow test which showed a significant moderate correlation. Patients tended to underscore their dysphagia when compared to the objective score measured by the mOBFRS. Preliminary results show that the mOBFRS is a sensitive measure and has the potential to be a useful tool in evaluating dysphagia in ALS. http://dx.doi.org/10.1016/j.nmd.2019.06.121 P.93 Small fiber neuropathy underlying autoinflammatory syndromes in children I. Shinkarevsy 1 , I. Nevo 1 , L. Harel 1 , G. Amarilyo 1 , A. Dori 2 , N. Agmon- Levin 2 , L. Kachko 1 , R. Dabby 3 , M. Rabie 1 , S. Aharoni 1 1 Schneider Children’s hospital, Petach-Tikva, Israel; 2 Chaim Sheba Medical Center, Tel Hashomer, Israel; 3 Wolfson Medical Center, Holon, Israel Small fiber neuropathy affecting the small A δ and C fibers is rare in children. Few data have been published on the etiology of small fiber neuropathy in the pediatric population. Metabolic, infectious, and toxic causes were described. It has been associated with several autoimmune disorders such as Sjogren disease, fibromyalgia and celiac disease, but there are no reports of an autoinflammatory etiology. The aim of the present study was to highlight the potential etiologic role of autoinflammatory syndromes, particularly familial Mediterranean fever, in small fiber neuropathy and erythromelalgia in the pediatric population. The data of four children presenting with erythromelalgia and neuropathic pain were collected retrospectively from the electronic database of a pediatric medical center. Clinical and electrophysiologic evaluation excluded large nerve fiber involvement. Skin biopsies confirmed small-fiber neuropathy. On genetic analysis, 2 children were homozygous and one was heterozygous for familial Mediterranean fever-associated MEFV mutations. The fourth child was diagnosed with Behcet disease. Treatment with anti-interleukin- 1, intravenous immunoglobulin, and glucocorticoid was beneficial. The diagnosis of small- fiber neuropathy should be considered in children presenting with erythromelalgia. A thorough investigation is needed to reveal the underlying disorder. Clinicians should be alert to the peripheral neurological manifestations of autoinflammatory syndromes because effective treatments are available. http://dx.doi.org/10.1016/j.nmd.2019.06.122 P.94 Peripheral myelin protein 2 - a novel mutation causing Charcot- Marie-Tooth neuropathy in a Bulgarian family T. Chamova 1 , P. Palaima 2 , V. Mitev 1 , C. Van Broeckhoven 2 , K. Peeters 2 , A. Jordanova 2 , I. Tournev 1 1 Medical University-Sofia, Sofia, Bulgaria; 2 University of Antwerp, Antwerp, Belgium Recently, the gene encoding peripheral myelin protein 2 (PMP2) was identified as a novel cause for demyelinating Charcot-Marie-Tooth neuropathy (CMT) with three mutations that structurally cluster together (p.Ile43Asn, p.Thr51Pro and p.Ile52Thr) reported in five families. Using whole exome sequencing and screening of a cohort of 241 patients diagnosed with demyelinating CMT we identified a novel missense mutations in PMP2 in a Bulgarian family with two affected patients from two consecutive generations (c.341C>T, p.Met114Thr). It affects highly conserved residues. The clinical and electrophysiological features in our family were consistent with a demyelinating polyneuropathy with onset in the first 2 years of life with delayed motor milestones in one of the patients. Foot deformities have been observed since the age of 2-3 years. Proximal muscle weakness in the lower limbs appeared in the second decade. Involvement of the upper limbs in terms of weakness and paresthesia became apparent in the third decade. Despite the early age at onset the clinical course was slowly progressive in both affected with preserved independent ambulation until the 7th decade. The conduction velocities of the median and ulnar nerves, obtained in the fourth decade were between 6-12 m/s. The MRI of the muscles of the lower limbs in one of the patients was consistent with most severe involvement of the peroneal muscles. Our findings expand the genetic and phenotypic spectrum of PMP2-related neuropathy. http://dx.doi.org/10.1016/j.nmd.2019.06.123 P.95 Walking speed in Charcot-Marie-Tooth disease: a marker of disease progression during childhood and adolescence G. Acsadi 1 , T. Wren 2 , K. Pierz 3 , S. Ounpuu 3 1 University of Connecticut, Farmington, USA; 2 Children’s Hosp. Los Angeles, Los Angeles, USA; 3 Connecticut Childrens, Farmington, USA The purpose of this study was to examine differences in walking speed as a measure of motor function in youth with CMT. The preferred walking speed of 22 youth with CMT1 (age 12.2 ± 3.1 years), 12 youth with CMT2 (age 9.8 ± 4.6 years), and 54 age matched healthy peers (9.6 ± 3.4 years) was measured using computerized gait analysis. Some patients were tested more than once resulting in 29 total CMT1 and 22 total CMT2 observations. Changes in walking speed with age were compared among groups using linear mixed effect models including a random intercept term to model the repeated measures for some participants. Walking speed increased with age in healthy controls (2.2 cm/sec/year; 95% CI: 0.7 to 3.6; p=0.004), however, it changed at a significantly lower rate and appeared to decrease with age in CMT1 (-2.2 cm/sec/year; 95% CI: -4.9 to 0.4; p=0.097) and CMT2 (- 2.4 cm/sec/year; 95% CI: -5.0 to 0.3; p=0.085). The differences in walking speed among groups were primarily due to change in stride length, which normally increased with age in control peers (4.4 cm per year; 95% CI: 3.5 to 5.4; p<0.001) but decreased with age in CMT1 (-2.1 cm/year; 95% CI: -3.8 to -0.3; p=0.02) and CMT2 (-1.8 cm/year; 95% CI: -3.4 to -0.1, p=0.38). Youth with CMT show a decline in walking speed with age compared to control peers. This appears to be a more severe and starts earlier for those with CMT2 vs. CMT1. The decline in walking speed was likely caused by reduced plantar flexor strength and increased ankle instability. Treatments that increase step length such as plantar flexor strengthening and bracing, which can also improve ankle stability in stance, are likely to improve walking speed and associated function such as keeping up with peers. Walking speed measurements might serve as an outcome measure in emerging therapeutic trials for CMT. http://dx.doi.org/10.1016/j.nmd.2019.06.124 P.96 Clinical and genetic aspects in Korean patients with hereditary spastic paraplegia H. Kim 1 , Y. Choi 2 , H. Park 3 1 Asan Medical Center, Seoul, Korea; 2 Gangnam Severance Hospital, Seoul, Korea; 3 Gangneung Asan Hospital, Gangneung, Korea Hereditary spastic paraplegia (HSP) is a genetically and clinically heterogeneous genetic disorder characterized by spastic paraparesis.