Motor neuron diseases (MNDs) are a wide group of neurodegenerative disorders characterized by the degeneration of a specific neuronal type located in the central nervous system, the motor neuron (MN). There are two main types of MNs, spinal and cortical MNs and depending on the type of MND, one or both types are affected. Cortical MNs innervate spinal MNs and these control a variety of cellular targets, being skeletal muscle their main one which is also affected in MNDs. A correct functionality of autophagy is necessary for the survival of all cellular types and it is particularly crucial for neurons, given their postmitotic and highly specialized nature. Numerous studies have identified alterations of autophagy activity in multiple MNDs. The scientific community has been particularly prolific in reporting the role that autophagy plays in the most common adult MND, amyotrophic lateral sclerosis, although many studies have started to identify physiological and pathological functions of this catabolic system in other MNDs, such as spinal muscular atrophy and spinal and bulbar muscular atrophy. The degradation of selective cargo by autophagy and how this process is altered upon the presence of MND-causing mutations is currently also a matter of intense investigation, particularly regarding the selective autophagic clearance of mitochondria. Thorough reviews on this field have been recently published. This chapter will cover the current knowledge on the functionality of autophagy and lysosomal homeostasis in the main MNDs and other autophagy-related topics in the MND field that have risen special interest in the research community.

运动神经元疾病（MND）是一大类神经退行性疾病，其特征在于位于中枢神经系统中的特定神经元类型即运动神经元（MN）的变性。MN有两种主要类型，即脊髓型和皮质型MN，根据MND的类型，一种或两种都会受到影响。皮质MNs支配着脊柱MNs，它们控制着多种细胞靶标，而骨骼肌是它们的主要靶标，骨骼肌也受到MNDs的影响。自噬的正确功能对于所有细胞类型的生存都是必需的，考虑到神经元的有丝分裂后和高度特化的性质，它对神经元尤为重要。许多研究已经确定了多种MND中自噬活性的改变。尽管许多研究已开始确定该代谢分解系统在其他MND中的生理和病理功能，例如脊髓性肌萎缩和脊髓损伤，但科学界在报道自噬在最常见的成人MND（肌萎缩性侧索硬化）中的作用方面尤为丰富。脊髓和延髓性肌萎缩。目前，自噬对选择性货物的降解作用以及在引起MND的突变后如何改变这一过程，目前也是一个深入研究的问题，特别是关于线粒体的选择性自噬清除。最近对该领域进行了详尽的评论。