Abstract:
Thai Sudden Unexplained Death Syndrome (Thai SUDS), or Lai-Tai, is a
major health problem among rural residents of northeastern Thailand. The cause has
been identified as a genetic disease. SUDS, a disorder found in Southeast Asia, is
characterized by an abnormal electrocardiogram with ST-segment elevation in leads
V1-V3, identical to that seen in Brugada Syndrome (Brugada Sign, BS). Sudden death
due to ventricular fibrillation cardiac arrest (represents an arrhythmogenic marker that
identifies high-risk SUDS). The SUDS victims have a sleeping disorder (narcolepsy).
The HLA-DR locus is tightly associated with narcoleptic Japanese patients. HLA-DR2
and DQ1. haplotypes were also found in Oriental narcoleptic patients. These
circumstances prompted us to study the association between the disease and HLA
Class II by HLA DNA typing using a PCR-SSO method. Five Thai SUDS families
were included in this study (18 BS-positive case subjects and 27 BS-negative control
subjects). We found that the HLA-DRB1*12021 allele was significantly increased in
BS-positive subjects (P=0.02; OR=4.5), the same as the HLA-DRB1*12021-
DQB1*0301/09 haplotype (P=0.01; OR=7.95). Our data suggest that HLA-DRB1*
12021 allele is associated with BS and the HLA-DRB1*12021-DQB1*0301/09 is a
haplotype susceptible to arrhythmogenic markers that can identify a high risk of
SUDS.Only HLA-DRB1*12021 allele shows preferential transmission and association
with high risk of SUDS (P<0.01,TDT=6.37).