Olfactory dysfunction in sporadic Parkinson's Disease and LRRK2 carriers.
OBJECTIVE
The aim of the study was to examine the sense of smell in LRRK2 mutation carriers and in patients with sporadic PD (sPD).


METHODS
A total of 343 individuals were included: 275 sPD of whom 90 were de novo patients with sPD, 17 LRRK2 PD, 36 healthy LRRK2 mutation carriers, and 15 healthy family members without mutation. All subjects underwent neurologic examination and olfactory sense testing with B-SIT (a 12-item test). Linear regression analysis was applied to build different models with B-SIT as dependent variable.


RESULTS
Sporadic PD had significantly lower scores in olfaction compared with LRRK2 PD (P < 0.001). B-SIT scores were lowest in medicated sPD, and higher scores were found in de novo patients. LRRK2 PD had similar sense of smell to healthy LRRK2 mutation carriers and to healthy family members without mutation when adjusting for age.


CONCLUSIONS
Hyposmia was pronounced already at time of diagnosis in the sPD cases but was not present in healthy LRRK2 mutation carriers and less pronounced in LRRK2 PD compared with sporadic cases. Smell testing may be a preclinical marker in sporadic PD but does not seem applicable in LRRK2 cases.
Department 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.
K K
KK
Johansen
B J
BJ
Warø
J O
JO
Aasly
D000367:Age Factors; D003430:Cross-Sectional Studies; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D008297:Male; D008875:Middle Aged; D009154:Mutation; D000857:Olfaction Disorders / Q000150:complications* / Q000235:genetics*; D010300:Parkinson Disease / Q000150:complications* / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012737:Sex Factors
C495280:LRRK2 protein, human; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D017346:Protein Serine-Threonine Kinases
B-SIT; LRRK2; Parkinson's disease; de novo; hyposmia; preclinical