Knowledgeable consent was waived by the Institutional Evaluate Board

Knowledgeable consent was waived by the Institutional Evaluate Board. Descriptive statistics were reported using frequencies and percentages for categorical variables and median and interquartile range (IQR) for continuous variables. Results This study included 14 patients (9 women) with a median age of 51.9?years (IQR 48C57). The most common presenting symptoms were painful paresthesia (100%), gait instability (42.9%), constitutional symptoms (42.9%), and autonomic symptoms (28.6%). Onset of symptoms was chronic (12?weeks) in eight patients (57.1%). Examination showed a distal loss of sensation to pin prick (100%), as well as impaired vibration sensation (78.6%) and proprioception (35.7%), in the distal extremities. We also observed mild weakness in the distal lower-extremities (42.9%). Three patients (21.4%) had trigeminal neuralgia, three patients (21.4%) had co-existing autoimmune disease, and one patient (7.1%) had SAR156497 a history of renal cell carcinoma. The mean titer of FGFR3 antibody was 14,285.71 (IQR 5000C16,750). All 14 patients produced normal results in the neuropathy workup. Nerve conduction study and electromyography showed sensory axonal neuropathy in four patients (28.6%), sensorimotor axonal neuropathy in seven patients (50%), and a normal result in three patients (21.4%). For those with a normal NCS/EMG, a skin biopsy showed a non-length-dependent small fiber neuropathy. Conclusions Neuropathy related to FGFR3 antibodies can potentially involve small and large fibers, sensory and motor fibers, and even the trigeminal nerve, which contributes to a highly variable clinical presentation. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-021-02090-2. Keywords: Autoimmune neuropathies, Anti-FGFR3 antibody, Sensory neuronopathies, Neuropathy Background Sensory neuronopathies (SNN) or ganglionopathies are a subgroup of peripheral nervous system diseases associated with the dysfunction of dorsal root ganglia (DRG) sensory neurons [1]. Like other types of sensory neuropathies, patient presentation of SNN depends on the type of nerve fiber that is affected, such as small or large fibers [2]. For instance, SNN results from damage to large afferent fibers and presents as sensory ataxia, but patients may also experience pain and paresthesia if there is damage to the small and medium-size neurons [3]. SNN is increasingly associated with an autoimmune pathogenesis, with common etiologies including paraneoplastic syndrome and Sjogrens syndrome [1]. Though electrophysiological studies, neuroimaging, and clinical features are typically considered when making the diagnosis of SNN, these current methods fail to distinguish etiologies from one another [4, 5]. Considering that the etiology of SNN is deemed idiopathic in nearly half of patients, these current methods also fall short in capturing the complex range of etiologies [3]. Interestingly, some patients with idiopathic SNN may later develop patterns consistent with dysimmune SSN, which may suggest an underlying autoimmune mechanism [5]. Fibroblast growth factors (FGFs) are peptides that play a physiological role in the development and regeneration in the peripheral nervous system [6]. FGFs bind to their receptors, called fibroblast growth factor receptors (FGFRs), that are present in both the peripheral and central nervous system in human adults [7]. One SAR156497 of the receptors, FGFR3, is known to be involved in nerve regeneration and axonal development [6]. The intracellular domain of FGFR3 was found to be a target of IgG antibodies in a subgroup of patients with sensory neuropathy, particularly in idiopathic or autoimmune-related cases [7]. Still, the exact role of FGFR3 antibodies in peripheral system diseases such as neuropathies SAR156497 remains unclear [8]. Though anti-FGFR3 antibodies were originally associated with purely sensory-predominant neuropathies or neuronopathies, recent studies suggest that the associated neuropathy and clinical manifestation can be rather diverse and imprecise [7C10]. The aim of the study is to report the clinical and electro diagnostic findings in a cohort of patients with sensory or sensorimotor polyneuropathy and anti-FGFR3 antibodies. Methods Study design This is a retrospective chart review of patients who presented at the University Mouse monoclonal to FGFR1 of Missouri with polyneuropathy and positive FGFR3 antibody from July 2015 to December 2017. In this timeframe, the University clinic evaluated a total of 1500 patients with sensory or sensorimotor polyneuropathy. We included length-dependent and non-length-dependent neuropathies, as well as small and large fiber SAR156497 neuropathies. Testing for FGFR3 antibody in a patient was prompted if both criteria 1 and 2 were met: (1) one or more clinical features of acute to subacute onset, fluctuating course of neuropathic symptoms, SAR156497 asymmetric non-length dependent pattern with or without sensory ataxia, or severe neuropathic pain (even if chronic and length-dependent), and (2) the following investigations for other etiologies of neuropathy were negative: HbA1c; 2-h glucose tolerance test if HbA1c was.