Constipation is significantly associated with an increased risk of cognitive impairment, which is consistent with the findings of Poplawska-Domaszewicz et al. They discovered that GBA1 gene mutations accelerate the pathological spread of α-synuclein through the gut-brain axis, leading to the co-occurrence of autonomic dysfunction (such as constipation) and cognitive decline in PD patients. Here, GBA1 is linked to Parkinson disease.