Daytime sleepiness and the COMT val158met polymorphism in patients with Parkinson disease.
OBJECTIVE
A preliminary study by our group suggested an association between daytime sleepiness and the catechol-O-methyltransferase (COMT) val158met polymorphism (rs4680) in patients with Parkinson disease (PD). We sought to confirm this association in a large group of patients with PD.


METHODS
Genetic association study in patients with PD.


METHODS
Movement disorder sections at 2 university hospitals.


METHODS
PD patients with and without episodes of suddenly falling asleep matched for antiparkinsonian medication, disease duration, sex, and age, who participated in a previous genetic study on dopamine-receptor polymorphisms.


METHODS
Not applicable.


RESULTS
In this study, 240 patients with PD (154 men; age 65.1 +/- 6.1 years; disease duration 9.4 +/- 6.0 years) were included. Seventy had the met-met (LL), 116 the met-val (LH), and 54 the val-val (HH) genotype. In the combined LL+LH group (featuring reduced COMT activity), the mean Epworth Sleepiness Scale (ESS) score was 9.0 +/- 5.9 versus 11.0 +/- 6.1 in the HH (high COMT activity) group (P = .047). Forty-seven percent of the LL and LH patients had sudden sleep onset compared with 61% of the HH patients (P = .07). Logistic regression, however, showed that both pathologic ESS scores (i.e., > 10) and sudden sleep onset were predicted by subjective disease severity (P < .001 each) but not by the COMT genotype.


CONCLUSIONS
Our previous finding that the L-allele may be associated with daytime sleepiness could not be confirmed in the present study. Altogether, our data do not support a clinically relevant effect of the COMT genotype on daytime sleepiness in PD.
Rissling
Ida
I
Department of Neurology, Philipps-University Marburg, Germany.
Frauscher
Birgit
B
Kronenberg
Florian
F
Tafti
Mehdi
M
Stiasny-Kolster
Karin
K
Robyr
Anne-Catherine
AC
Körner
Yvonne
Y
Oertel
Wolfgang Hermann
WH
Poewe
Werner
W
Högl
Birgit
B
Möller
Jens Carsten
JC
D000368:Aged; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002940:Circadian Rhythm; D003062:Codon; D006970:Disorders of Excessive Somnolence / Q000453:epidemiology* / Q000235:genetics*; D004298:Dopamine / Q000235:genetics*; D018491:Dopamine Agonists / Q000627:therapeutic use; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy / Q000453:epidemiology*; D011110:Polymorphism, Genetic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D003062:Codon; D018491:Dopamine Agonists; D002394:Catechol O-Methyltransferase; D004298:Dopamine