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Olfactory Assays for Mouse Models of Neurodegenerative Disease
Published on: August 25, 2014
Olfactory dysfunction in sporadic Parkinson's Disease and LRRK2 carriers
K K Johansen1, B J Warø, J O Aasly
1Department of Neurology, St Olavs University Hospital, Norwegian University of Science and Technology, Trondheim, Norway; Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
Acta Neurologica Scandinavica
|August 14, 2013
Summary
Smell dysfunction is prominent in sporadic Parkinson's disease (sPD) at diagnosis. However, LRRK2 mutation carriers, including those with Parkinson's disease, show preserved or less severe olfactory deficits.
Area of Science:
- Neurology
- Genetics
- Olfactory Neuroscience
Background:
- Parkinson's disease (PD) is a neurodegenerative disorder with diverse etiologies, including genetic (LRRK2 mutations) and sporadic forms.
- Olfactory dysfunction (hyposmia) is a common non-motor symptom in PD, potentially appearing years before motor symptoms.
- The role of LRRK2 mutations in PD pathogenesis and their impact on olfactory function remain areas of active investigation.
Purpose of the Study:
- To investigate and compare olfactory sense between patients with sporadic PD (sPD) and individuals carrying LRRK2 mutations.
- To evaluate olfactory function in healthy LRRK2 mutation carriers and their family members as controls.
Main Methods:
- A cohort of 343 individuals was studied, including sPD patients (de novo and medicated), LRRK2-associated PD patients, and healthy controls (LRRK2 mutation carriers and non-carriers).
- Neurologic examinations and olfactory testing using the Brief Smell Identification Test (B-SIT) were performed on all participants.
- Linear regression models were employed to analyze the relationship between B-SIT scores and participant groups, adjusting for age.
Main Results:
- Sporadic PD patients exhibited significantly lower B-SIT scores compared to LRRK2-associated PD patients (P < 0.001).
- Olfactory scores were lowest in medicated sPD patients and higher in de novo sPD patients.
- LRRK2-PD patients demonstrated olfactory function comparable to healthy LRRK2 mutation carriers and non-carrier family members after age adjustment.
Conclusions:
- Pronounced hyposmia is evident at diagnosis in sPD, suggesting smell testing as a potential preclinical marker for sporadic PD.
- Healthy LRRK2 mutation carriers did not present with hyposmia, and LRRK2-PD patients showed less severe olfactory deficits than sporadic PD cases.
- Olfactory testing may not be a suitable diagnostic or preclinical marker for LRRK2-related Parkinson's disease.
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