Narcolepsy 5, Susceptibility To
For a phenotypic description and a discussion of genetic heterogeneity of narcolepsy, see 161400.
MappingHallmayer et al. (2009) performed genomewide association studies on 807 patients with narcolepsy and 1,074 controls of mixed European ancestry. All cases were HLA-DQB1*0602 positive and all had clear-cut cataplexy. Among the 23% with hypocretin-1 (HCRT; 602358) measurements, all were found to be deficient. The authors identified significant association with 3 SNPs in linkage disequilibrium on chromosome 14q11.2: rs1154155 (p = 1.9 x 10(-13)), rs12587781 (p = 3.03 x 10(-13)), and rs1263646 (p = 4.86 x 10(-12)). All SNPs were located within an 18-kb segment in the TCRA locus containing the joining (J) segment subregion (see 615443) to intron 1 of the constant region (TRAC; 186880). The findings were replicated in a cohort of 1,057 cases and 1,104 controls. The 1,057 cases including 259 Caucasian, 104 European, 433 Japanese, 128 Korean, and 133 African American patients. The combined results showed an average odds ratio of 1.69 for the minor C allele of rs1154155 (p less than 10(-21)).