Olfactory Dysfunction in Parkinson’s Disease Patients with the LRRK2 G2385R Variant

Abstract

Olfactory dysfunction has been reported in Parkinson's disease (PD) patients carrying the LRRK2 G2019S variant in Caucasians but rarely in those with the LRRK2 G2385R variant. In this study, we performed genotyping for the LRRK2 G2385R variant in PD patients recruited from the Movement Disorder Clinic of Xuanwu Hospital in Beijing and in healthy controls randomly selected from the Beijing Longitudinal Study on Aging cohort. The ''five-odor olfactory detection array'', an olfactory threshold test, was used to assess olfactory function. One hundred and eighty-six participants were enrolled, comprising 43 PD patients without (iPD) and 25 with (LRRK2-PD) the LRRK2 G2385R variant, and 118 healthy controls. Our results showed that the threshold of olfactory identification was significantly worse in PD patients than in controls, but not significantly different between the iPD and LRRK2-PD groups. These findings suggested that although olfactory function in LRRK2-PD patients is impaired, it is similar to that in iPD patients.

RETRACTED ARTICLE: Alpha-synuclein overexpression in the olfactory bulb initiates prodromal symptoms and pathology of Parkinson’s disease

“…Significant dysfunctions in the central nervous system in PD are thought to persist for several years before the onset of the classical motor syndrome, defining the prodromal phase. The prodromal phase in PD is a crucial period in the disease progression and is characterized by non-motor symptoms such as autonomic disturbances, depression, sleep disorders and, interestingly, olfactory dysfunction [ 5 , 6 ].…”

Spotlight on olfactory dysfunction in Parkinson's disease

“…Olfactory impairment is not present in healthy LRRK2 carriers, while only very mild hyposmia is found in LRRK2 PD patients. [84][85][86][87] Smell testing may be useful as a supportive marker for differentiating LRRK2 PD from idiopathic PD in the absence of genetic testing.…”

Age-Dependent Alpha-Synuclein Accumulation and Phosphorylation in the Enteric Nervous System in a Transgenic Mouse Model of Parkinson’s Disease

“…Clinically, patients with PD exhibit typical motor symptoms, such as resting tremor, bradykinesia, and rigidity. At early stages of the disease, PD patients often exhibit non-motor symptoms, such as olfactory malfunction, constipation, depression, and dementia, which severely affect their quality of life [2][3][4][5]. To date, the mechanisms underlying these non-motor symptoms have yet to be fully understood.…”