THE HLA ASSOCIATION WITH GRAVES-DISEASE IS SEX-SPECIFIC IN HONG-KONG CHINESE SUBJECTS

OBJECTIVE Graves' disease is associated with different HLA genes in Ca ucasians and the Chinese, in whom the HLA associations may be stronger in males than females. Common HLA-associated susceptibility in both r aces may occur at the HLA-DQ loci. The aims of this study were to exam ine the HLA-A, B, DR and DQ associations with Graves' disease in a Hon g Kong Chinese population and to determine whether the HLA association s differ between the sexes and between subjects with and without thyro toxic periodic paralysis. DESIGN HLA-A, B and DR types were determined by serological typing and DQA1 and DQB1 alleles by oligonucleotide pr obing of the respective enzymatically amplified gene. PATIENTS Ninety- seven Chinese patients with Graves' disease (31 males with, 35 males w ithout and 31 females without thyrotoxic periodic paralysis) and 105 r acially matched healthy controls. MEASUREMENTS Frequencies of HLA type s/alleles at each locus were compared between patients and controls an d between the Graves' subgroups using the chi(2)-test. RESULTS HLA-B46 , DR9 and DQB10303 were associated with Graves' disease in mates only ; these associations were weaker in males with thyrotoxic periodic par alysis. DR12, DQA10401 and DQB1*0301 were protective, regardless of s ex or the presence of thyrotoxic periodic paralysis. The positive HLA associations in the Hong Kong Chinese were distinct from those in Cauc asians whereas the protective haplotype was similar to that described in Caucasians. CONCLUSIONS These findings call in question the role of HLA genes in disease susceptibility but suggest a role for HLA in pro tection from Graves' disease.