Aspartic acid at position 57 of the HLA-DQ beta chain is not protective against insulin-dependent diabetes mellitus in Japanese people.
Insulin-dependent diabetes mellitus (IDDM) in Caucasians is closely associated with the HLA-DQ gene, especially the residue 57 of the DQ beta chain. Aspartic acid at this position provides protection against IDDM, and substitution of this residue by alanine, valine or serine increases susceptibility to IDDM. To determine whether this is a common feature of IDDM in different ethnic groups, we studied DQB1 DNA in Japanese patients with IDDM by polymerase chain reaction and non-radioactive restriction site analysis. In contrast to Caucasian patients with IDDM, most Japanese patients with IDDM possessed at least one aspartic acid at position 57 of DQ beta. This finding strongly suggests that aspartic acid at position 57 of DQ beta does not protect the Japanese from IDDM.
Ikegami
H
H
Department of Geriatric Medicine, Osaka University Medical School, Japan.
Tahara
Y
Y
Cha
T
T
Yamato
E
E
Ogihara
T
T
Noma
Y
Y
Shima
K
K
D000596:Amino Acids / Q000032:analysis; D001224:Aspartic Acid; D001483:Base Sequence; D003922:Diabetes Mellitus, Type 1 / Q000208:ethnology* / Q000235:genetics / Q000276:immunology; D006683:HLA-DQ Antigens / Q000235:genetics*; D006801:Humans; D007564:Japan; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
D000596:Amino Acids; D006683:HLA-DQ Antigens; D001224:Aspartic Acid