Amyotrophic lateral sclerosis (ALS) is a late-onset neurodegenerative condition, most widely characterized by the selective vulnerability of motor neurons and the poor life expectancy of afflicted patients. Limited disease-modifying therapies currently exist, which only further attests to the substantial heterogeneity associated with this disease. In addition to established prognostic factors like genetic background, site of onset, and age at onset, wide consensus on the role of neuroinflammation as a disease exacerbator and driver has been established. In lieu of this, the emerging literature on chitinases in ALS is particularly intriguing. Individual groups have reported substantially elevated chitotriosidase (CHIT1), chitinase-3-like-1 (CHI3L1), and chitinase-3-like-2 (CHI3L2) levels in the cerebrospinal, motor cortex, and spinal cord of ALS patients with multiple-and often conflicting-lines of evidence hinting at possible links to disease severity and progression. This mini-review, while not exhaustive, will aim to discuss current evidence on the involvement of key chitinases in ALS within the wider framework of other neurodegenerative conditions. Implications for understanding disease etiology, developing immunomodulatory therapies and biomarkers, and other translational opportunities will be considered.

中文翻译：

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几丁质酶作为肌萎缩性侧索硬化症的生物标志物：来自中枢神经系统及其以外的信号。

肌萎缩性侧索硬化症（ALS）是一种迟发性神经退行性疾病，其最广泛的特征是运动神经元的选择性脆弱性和患病患者的预期寿命差。当前存在有限的疾病改良疗法，这仅进一步证明了与该疾病相关的实质异质性。除了确定的预后因素，如遗传背景，发病部位和发病年龄外，人们对于神经炎症作为疾病加重者和驱动者的作用也已达成广泛共识。取而代之的是，有关ALS中几丁质酶的新兴文献特别引人入胜。各个小组的报告均显示，脑脊髓，运动皮层中的壳三糖苷酶（CHIT1），几丁质酶3-样1（CHI3L1）和几丁质酶3-样2（CHI3L2）明显升高，ALS患者的脊髓和多条证据（通常是相互冲突的证据）暗示可能与疾病的严重程度和进展有关。这篇简短的综述虽然并不详尽，但旨在探讨在其他神经退行性疾病的更广泛框架内，ALS中关键几丁质酶参与的最新证据。将考虑了解疾病病因，开发免疫调节疗法和生物标记物以及其他转化机会的意义。