Aim:In Japan, the government and media have become aware of the issues of early onset dementia (EOD), but policies for EOD have not yet been established and support systems are inadequate. To provide practical data about EOD, a two-step postal survey was performed.Methods: A questionnaire requesting information on EOD cases was sent to target institutions in five catchment areas in Japan. According to the answers from the institutions, we estimated the prevalence of EOD using census data and determined the illnesses causing EOD. As a quality control study, the authors reviewed every diagnosis in a quarter of the reported cases using the medical and psychiatric records and neuroimaging data. This study was conducted from 2006 to 2007. Results:Information from 2469 patients was collected from 12 747 institutions, and 2059 subjects with EOD were identified. The estimated prevalence of EOD was 47.6 per 100 000 (95% confidence interval, 47.1-48.1) for all of Japan. Of the illnesses causing EOD, vascular dementia (VaD) was the most frequent (39.8%), followed by Alzheimer's disease. Conclusions:The prevalence of EOD in Japan appeared to be similar to that in Western countries. However, unlike previously reported international experience, VaD was the most frequent cause of EOD in all catchment areas in Japan.

No abstract

No abstract

HLA phenotypes of 54 patients with tuberculoid leprosy were compared with those of 167 healthy controls. Frequencies of HLA-A, -B and -C antigens did not differ significantly between the leprosy patients and the controls. However, an increase in the frequencies of DR1, DR2, DRW8 and MT1 antigens and a decrease in the frequencies of DR4 and MT3 antigens were observed in the leprosy patients. Statistical evidence was presented that MT1 antigens were primarily associated with tuberculoid leprosy in Japanese patients rather than DR2.

Four patients with mental illness were found to be deficient in plasma α1,3-fucosyltransferase for the first time in Japan [Exp Clin Immunogenet 1999;16:125–130]. Complete sequencing of FUT6 genes in these individuals revealed the presence of two point mutations, i.e., G739 to A (Glu→247 to Lys) and C945 to A (Tyr→315 to stop). In addition to two reported alleles having G739 to A (pf1) and G739 to A and C945 to A (pf3), a new mutated allele having C945 to A (pf2) was found to be present and all the individuals who lack α1,3-fucosyltransferase activity in plasma were found to possess pf genes homozygously (pf/pf). In order to detect such lethal mutations in FUT6 genes easily, PCR-RFLP methods have also been developed and applied for the screening of FUT6 deficiency in a large number of samples which resulted in the demonstration of three additional FUT6-deficient individuals. The absence of α1,3-fucosylated molecules on α₁-acid glycoprotein in plasma from all the 7 individuals was confirmed to result from the plasma α1,3-fucosyltransferase deficiency.