Hereditary sensory autonomic neuropathy (HSAN) type II is a rare, autosomal recessive, and early onset sensory neuropathy, characterized by severe and progressive sensation impairment, leading to ulcero‐mutilating complications. FAM134B gene, also known as RETREG1 gene, mutations have been reported to be associated to HSAN‐IIB. We report four patients from two unrelated families who developed during childhood a sensory axonal neuropathy with variable severity and pronounced nociception impairment. Complications such as recurrent ulcerations, osteomyelitis, and osteonecrosis leading to distal amputation were noticed. Dysautonomia was mild or even absent in our group of patients. Additionally, either clinical or neurophysiological motor impairment was not uncommon. Presence of upper motor neuron signs was also a distinctive feature in two related patients. After extensive workup, two novel homozygous mutations in the FAM134B gene were identified. This report expands the clinical and genetic spectrum of HSAN type II and emphasizes the phenotype variability even within the same family.

中文翻译：

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遗传性感觉自主神经病II型：FAM134B基因中两个新突变的报道。

II型遗传性感觉自主神经病（HSAN）是一种罕见的常染色体隐性遗传和早期发作的感觉神经病，其特征是严重和进行性感觉受损，导致致残残的并发症。FAM134B基因，也称为RETREG1基因，据报道突变与HSAN-IIB有关。我们报告了来自两个无关家庭的四名患者，这些患者在儿童时期发展为感觉轴突神经病，病情轻重不一，明显伤害感受明显。注意到并发症如复发性溃疡，骨髓炎和坏死导致远端截肢。在我们的患者组中，自主神经异常轻度甚至不存在。此外，临床或神经生理学上的运动障碍并不少见。上运动神经元体征的存在也是两名相关患者的显着特征。经过大量检查后，FAM134B中出现了两个新的纯合突变基因被鉴定。该报告扩展了HSAN II型的临床和遗传谱，并强调了即使在同一家族中的表型变异性。