HLA-DR types in Japanese schizophrenics: analysis by group-specific PCR amplification

An association of HLA-DR8 and DR1 with DSM-III schizophrenia has been reported in Japan (Miyanaga et al. (1984) Biol. Psychiatr. 19, 121-129). To further investigate this preliminary finding, we compared HLA-DR types in 44 unrelated Japanese schizophrenics (DSM-III-R) with those in 51 unrelated, healthy Japanese volunteers. Group-specific PCR amplification was used in the determination of HLA-DR in the patients. No significant difference was observed in the frequency of any DR types between patients and controls, after statistical correction for multiple testing. However, the frequency of DR1 in our patients (23%) and controls (10%) was almost the same as those in the previous report (22% vs. 10%), which means that there is a suggestive trend which could become significant if numbers were larger. It is argued that an exact determination of HLA-DR by DNA typing is important in current HLA studies of schizophrenia.