OBJECTIVE Sensory neuropathies (SNs) are often classified as idiopathic even if immunological mechanisms can be suspected. Antibodies against the intracellular domain of the fibroblast growth factor receptor 3 (FGFR3) possibly identify a subgroup of SN affecting mostly the dorsal root ganglion (DRG). The aim of this study was to identify the frequency of anti-FGFR3 antibodies and the associated clinical pattern in a large cohort of patients with SN. METHODS A prospective, multicentric, European and Brazilian study included adults with pure SN. Serum anti-FGRF3 antibodies were analysed by ELISA. Detailed clinical and paraclinical data were collected for each anti-FGFR3-positive patient and as control for anti-FGFR3-negative patients from the same centres ('center-matched'). RESULTS Sixty-five patients out of 426 (15%) had anti-FGFR3 antibodies, which were the only identified autoimmune markers in 43 patients (66%). The neuropathy was non-length dependent in 89% and classified as sensory neuronopathy in 64%, non-length-dependent small fibre neuropathy in 17% and other neuropathy in 19%. Specific clinical features occurred after 5-6 years of evolution including frequent paresthesia, predominant clinical and electrophysiological involvement of the lower limbs, and a less frequent mixed large and small fibre involvement. Brazilians had a higher frequency of anti-FGFR3 antibodies than Europeans (36% vs 13%, p<0.001), and a more frequent asymmetrical distribution of symptoms (OR 169, 95% CI 3.4 to 8424). CONCLUSIONS Anti-FGFR3 antibodies occur in a subgroup of SN probably predominantly affecting the DRG. Differences between Europeans and Brazilians could suggest involvement of genetic or environmental factors.

中文翻译：

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抗FGFR3自身抗体对感觉神经病的临床表征。

目的感觉神经病（SNs）通常被归类为特发性病，即使可以怀疑免疫机制。针对成纤维细胞生长因子受体3（FGFR3）胞内结构域的抗体可能确定了一个SN亚型，主要影响背根神经节（DRG）。这项研究的目的是确定大量SN患者中抗FGFR3抗体的频率以及相关的临床模式。方法一项前瞻性，多中心，欧洲和巴西的研究纳入了纯SN成年人。通过ELISA分析血清抗FGRF3抗体。从同一中心（“中心匹配”）收集每位抗FGFR3阳性患者的详细临床和副临床数据，并作为抗FGFR3阴性患者的对照。结果426例患者中有65例（15％）具有抗FGFR3抗体，这是43例患者（66％）中唯一鉴定出的自身免疫标志物。神经病是89％的非长度依赖性，分类为64％的感觉神经病，17％的非长度依赖性小纤维神经病和19％的其他神经病。在经过5-6年的进化后，出现了特定的临床特征，包括频繁的感觉异常，下肢的主要临床和电生理学受累以及较少的混合大，小纤维受累。巴西人的抗FGFR3抗体频率比欧洲人高（36％比13％，p <0.001），并且症状的不对称分布更为频繁（OR 169，95％CI 3.4至8424）。结论抗FGFR3抗体存在于SN的亚组中，可能主要影响DRG。