GAA and disorder of glycogen metabolism: Pompe disease (PD), as a type II autosomal recessive glycogen storage disorder, its core cause is the mutation of the gene encoding lysosomal GAA, which leads to the deficiency of GAA, blocking the degradation steps of glycogen by lysosomes during the process of autophagy (rather than the fusion disorder of autophagosomes and lysosomes), ultimately resulting in abnormal accumulation of glycogen in lysosomes[99–102].