Study on the Effects of Single Nucleotide Polymorphisms in Aquaporin-4 (AQP4) Gene on the Clinical Phenotype in Patients With Idiopathic and Familial Parkinson's Disease.

Parkinson's Disease (PD) is a progressive neurodegenerative disease characterized by the abnormal deposition in the brain of aggregates called Lewy Bodies, packed with a protein called α-synuclein. The mechanisms why this protein accumulates in the brain of patients with PD, as well as its relationship with clinical symptoms, is unknown.

Recently, an internal mechanism of drainage of waste proteins called glymphatic system has been identified and characterized. This system is silent during wakefulness and works during sleep. When it is active, a virtual space between the blood capillaries and cells of the brain called astrocytes opens and lets out waste products from the brain. This process is mediated by a protein of the astrocytes called Aquaporin-4 (AQP4). Preclinical studies have shown that the function of this system could be critical for the clearance of β-amyloid, a protein linked with the development of Alzheimer's Disease. Studies in humans have shown that genetic variations some parts of the AQP4 gene, defined as single nucleotide polymorphisms, may increase the likelihood to develop an aggressive form of Alzheimer's Disease. However, no studies in humans have ever been performed in Parkinson's disease and α-synuclein.

In this study, the investigators aim to elucidate whether genetic variations in the AQP4 gene contribute to variations in the clinical presentation and progression of sporadic and genetic forms of Parkinson's disease. To do so, the genetic profile of patients will be determined through a small venous blood sample collection. This will be coupled with clinical and sleep assessment.