ANALYSIS OF A CHINESE POPULATION SUGGESTS THAT THE TNFB GENE IS NOT ASUSCEPTIBILITY GENE FOR GRAVES-DISEASE

Graves' disease is associated with different HLA genes in different ra ces. The TNFB gene lies between the class I and class II HLA genes and has two alleles, TNFB1 and TNFB*2. Studies in Caucasians have sugges ted that the TNFB gene might be a susceptibility gene for Graves' dise ase. To investigate further the role of TNFB in predisposition to Grav es' disease, we determined whether the TNFB disease associations in th e Chinese were similar to those in Caucasians. A total of 57 patients with Graves' disease (32 male) were studied. A TNFB gene fragment was amplified from genomic DNA by using the polymerase chain reaction and digested with Nco I to distinguish the TNFB alleles (TNFB1 and TNFB*2 ). Genotype frequencies were compared with those in a racially matched group of 32 controls. TNFB1 homozygosity occurred in 15 (26%) Graves ' and 22 (24%) control subjects. TNFB1/TNFB*2 heterozygosity occurred in 29 (51%) and 48 (52%) and TNFB2 homozygosity in 13 (23%) and 22 ( 24%), respectively (NS). There were gender differences in the frequenc ies of TNFB1 homozygosity (13 male [41%], 2 female [8%]) TNFB*1/TNFB* 2 heterozygosity (13 male [41%], 16 female [64%]) (x(2) = 7.3, p = 0.0 2), and TNFB2 frequency (19 male [53%], 23 female [92%]; p(c) = 0.04) in Graves' patients. We conclude that the TNFB associations with Grav es' disease in the Hong Kong Chinese differ between the genders and fr om those described in Caucasians. The TNFB gene is not a susceptibilit y gene for Graves' disease.