Expression of Human Leukocyte Antigen DQB1*0602 in Korean Patients with Narcolepsy

Hong, S C; Woo, Y S; Park, S A; Jeong, J H; Han, J H; Kim, L; Lee, S P

Abstract

INTRODUCTION: Narcolepsy, a sleep dosorder characterized by excessive daytime sleepiness and cataplexy, is known to be closely associated with the human leukocyte antigen (HLA) DQB1*0602. Several studies have suggested that HLA-DQB1*0602 is strongly linked with narcolepsy-cataplexy. However, no studies have yet been made on whether HLA DQB1*0602 is associated with Korean patients with narcolepsy. This study was designed to investigate the frequency of HLA-DQB1*0602 of Korean patients with narcolepsy.
METHODS
Twenty patients were selected (mean age : 28.2+/-3.0, 11 men and 9 women). The patients were confirmed to have narcolepsy by the overnight polysomnography and multiple sleep latency test (MSLT) in addition to their clinical history and symptom at St, Vincent's Hospital and Korea University Hospital Sleep Disorders Clinic. Any subjects co-morbid with other hypersomnic sleep disorders such as sleep apnea or periodic limb movements during sleep were excluded. Clinical data was collected through a semi-structured interview for narcoleptic patients. All patients and 21 control did HLA typing for the presence of DQB1*0602.
RESULTS
OBTAINED WERE AS FOLLOWS: 1) Mean sleep latency was 2.4(+/-2.0 minutes) and mean frequency of sleep-onset REM period was 3.0(+/-1.6)by MSLT. 2) Characteristic symptoms of narcolepsy investigated were as follows: excessive daytime sleepiness (100%), cataplexy (100%), sleep paralysis (60%), hypnagogic hallucination (70%) and disrupted nocturnal sleep (75%). 3) Strong emotional expression such as laughing (80%) and joking (70%) triggered cataplexy which affects the knee and leg region (80%) and jaw region (30%). 4) HLA-DR2 was found in 90% of patients and 35% in controls. The frequency of HLA-DQB1*0602 in patients and controls was 90%, and 24%, respectively.
CONCLUSIONS
These results, which exhibit high HLA-DQB1*0602 expression in Korean patients with narcolepsy, suggest that HLA-DQB1*0602 could be a strong genetic marker in narcolepsy.