Clinical aspects of narcolepsy-cataplexy across ethnic groups.
OBJECTIVE
The objectives of this study were to compare severity and clinical presentation for narcolepsy-cataplexy across various ethnic groups. A large sample of narcoleptic patients was also used to further describe symptomatology and natural history for this sleep disorder.


METHODS
Retrospective review of clinical data ascertained from the Stanford Sleep Inventory, polysomnography and MSLT data, as well as clinical notes. Ethnicity was narrowly defined as African (Black) Americans, Caucasians, Asians, and Latinos when both parents and the subject identified with a given ethnic group.


METHODS
N/A.


METHODS
We compared the severity and clinical presentation of narcolepsy in 64 African Americans, 353 Caucasians, 32 Asians, 26 Latinos, and 9 subjects of mixed ethnicity. Subjects were recruited through the Stanford center for narcolepsy research.


METHODS
N/A.


RESULTS
A striking similarity in symptomatology, age of onset, and disease severity was found across ethnic groups. Mean age of onset for sleepiness, hypnagogic hallucinations, sleep paralysis and cataplexy were 19.20, 19.50, 20.11 and 23.02 years old. We also found that narcoleptic patients have slightly but significantly elevated body mass index relative to normative data (106.6% of matched controls, p<0.005) and are born slightly more frequently during the month of March. A tight correlation between our previously validated cataplexy scale and DQB1*0602 positivity was observed. Two thirds of patients reported having cataplexy with laughing, 92% of those being DQB1*0602 positive independent of ethnicity.


CONCLUSIONS
These results confirm the similarities in clinical presentation and natural history of narcolepsy-cataplexy in a large number of patients of various ethnic groups and cultural backgrounds.
Okun
Michele L
ML
Center For Narcolepsy, Stanford University, Department of Psychiatry and Behavioral Sciences, Palo Alto, CA 94304-5742, USA.
Lin
Ling
L
Pelin
Zerrin
Z
Hong
Sungchul
S
Mignot
Emmanuel
E
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D017668:Age of Onset; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers / Q000235:genetics; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D006683:HLA-DQ Antigens / Q000235:genetics; D059866:HLA-DQ beta-Chains; D006212:Hallucinations / Q000175:diagnosis / Q000453:epidemiology; D006630:Hispanic or Latino / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D017286:Polysomnography / Q000379:methods; D012720:Severity of Illness Index; D020188:Sleep Paralysis / Q000175:diagnosis / Q000453:epidemiology; D012895:Sleep, REM / Q000502:physiology*; D044465:White People / Q000706:statistics & numerical data*
D017931:DNA Primers; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D008562:Membrane Glycoproteins