FOXP3/Scurfin, a member of forkhead/winged-helix proteins, is involved in the regulation of T-cell activation, and essential for normal immune homeostasis. The FOXP3/Scurfin gene is located on chromosome Xp11.23, which includes one of the type 1 diabetes susceptible loci. Therefore, we investigated whether the human FOXP3/Scurfin gene might be a new candidate gene for type 1 diabetes. We first screened the human FOXP3/Scurfin gene for microsatellite and single nucleotide polymorphisms. Next, we performed an association study between the FOXP3/Scurfin gene and type 1 diabetes. Then, the evaluation of promoter/enhancer activity of the intron with (GT)(n) polymorphism was performed by dual luciferase reporter assay. We demonstrated two regions contained microsatellite polymorphisms; one was (GT)(n), located on intron zero and the other (TC)(n) on intron 5, which were under linkage-disequilibrium. The (GT)(15) allele showed a significantly higher frequency in patients with type 1 diabetes than in controls (43.1% vs 32.6%, P=0.0027). The genotype frequencies of (GT)(15)/(GT)(15) in female patients and of (GT)(15) in male patients tended to be higher than those in female ( P=0.064) and male ( P=0.061) controls, respectively. A significant difference in the enhancer activity between (GT)(15) and (GT)(16) dinucleotide repeats was detected. In conclusion, the FOXP3/Scurfin gene appears to confer a significant susceptibility to type 1 diabetes in the Japanese population.

GH has many effects on metabolism in addition to promoting growth. We studied changes in body composition and lipid profiles during and after GH treatment in 94 children with GH deficiency. Sixty-two subjects (46 boys and 16 girls) were evaluated at the beginning and during 36 months of GH treatment. The other 32 (21 boys and 11 girls) who had already been treated with GH were examined after the discontinuation of GH for a 6-month period. The height SD scores at the beginning and the discontinuation of GH treatment were -2.81 and -1.34 in boys and -3.14 and -1.38 in girls, respectively. The percent body fat (BF) significantly decreased from 16.5% to 11.7% in boys and from 16.7% to 11.6% in girls during the first 6 months of GH treatment (P < 0.01). BF subsequently remained constant in boys, but started to increase in girls from the 18th month of treatment. Lean body mass (kilograms) increased linearly throughout the treatment in both sexes (P < 0.01). Mean total cholesterol (TC) values decreased as a result of marked declines in low density lipoprotein cholesterol in both sexes, although statistical significance was detected only in boys (P < 0.01). High density lipoprotein cholesterol (HDLC) and apolipoprotein AI (Apo-AI) rapidly increased only in boys (P < 0.01). Triglyceride, Apo-AII, Apo-B, Apo-CII, Apo-CIII, Apo-E, and lipoprotein(a) showed no significant changes compared with baseline levels. Mean TC/HDLC and Apo-B/Apo-AI ratios decreased during treatment in both sexes, but the difference from baseline was significant only in boys (P < 0.01). After discontinuation of GH treatment, BF increased, and lean body mass decreased in boys (P < 0.01), whereas these variables did not change in girls. TC and low density lipoprotein cholesterol increased in boys within 6 months of discontinuing GH (P < 0.05). Other lipoproteins did not change in either sex, except for lipoprotein(a), which decreased significantly 6 months after the cessation of GH treatment in boys (P < 0.01). The mean TC/HDLC and Apo-B/Apo-AI ratios increased in boys slightly, but insignificantly. We concluded that GH treatment has beneficial effects on body composition and lipid profiles in both boys and girls with GH deficiency, although there are considerable gender differences. These beneficial effects of GH were reversed after the discontinuation of GH treatment, suggesting an important role of GH for GH-deficient children in the maintenance of normal metabolism even after the completion of linear growth.

Co-stimulatory molecules of CD28, cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and the newly identified inducible co-stimulator (ICOS) are expressed on cell surfaces and provide regulatory signals for T-cell activation. Their genes are candidate susceptibility genes for type 1 diabetes because they co-localize to Chromosome 2q33 with the IDDM12 locus. After determining the genomic structure and screening for polymorphisms of the ICOS gene, we performed association studies between newly identified polymorphisms of the ICOS gene, together with known polymorphisms of CD28 and CTLA-4 genes, and type 1 diabetes. The 49A/G dimorphism in exon 1 and the (AT)n in the 3' untranslated region of the CTLA-4 gene were significantly associated with type 1 diabetes. Evaluation of the CTLA-4 49A-3'(AT)n 86-bp haplotype frequency in patients and controls confirmed the results from the analysis of each polymorphic site. Dimorphism in intron 3 of the CD28 gene was associated with type 1 diabetes only in the early-onset group. In contrast, there was no association with the microsatellite polymorphisms in the ICOS gene or dimorphisms in the promotor region of CTLA-4. Of the three genes encoding co-stimulatory molecules, the CTLA-4 gene appears to confer risks for the development of type 1 diabetes.

Interaction between Programmed cell death-1 (PD-1), a member of costimulatory molecules, and its receptors Programmed cell Death-1 Ligand 1 (PD-L1) and Programmed cell Death-1 Ligand 2 (PD-L2), play an important role in the negative regulation of immune reactions. It was shown that a polymorphism in a regulatory site of the PD-1 gene was associated with susceptibility to several autoimmune diseases in various ethnic groups, whereas the contribution of the PD-1 gene or its ligand genes to the onset of type 1 diabetes (T1D) mellitus in the Japanese population remains unknown. We first screened PD-1, PD-L1, and PD-L2 genes for polymorphisms in the Japanese population, and then investigated the frequencies of polymorphisms in patients with T1D mellitus in comparison with healthy controls. In total, we identified 26 polymorphic sites within these genes, and then 23 polymorphisms with minor allele frequencies greater than 5% were intensively analyzed for genotyping in the patients and the controls. As a result, allele and genotype frequencies of the polymorphism numbers 2, 3, 4, 5, 6, and 8 in the PD-1 gene were different to some extent between the patients and the controls with P < 0.05, which did not reach statistical significance after the correction of multiple comparisons. Allele or genotype frequencies of any SNPs in the PD-L1 or PD-L2 gene did not show differences between the patients and the controls. The frequencies of the estimated haplotypes, those of which consisted of polymorphism numbers 2, 3, 4, 5, 6, and 8 in the PD-1, were significantly different between the patients and the controls (P = 0.00095). The in vitro assessment for a transcription activity of each haplotype of the PD-1 gene by luciferase assay did not demonstrate a functional difference between the haplotypes. In conclusion, the genetic evaluation by association study demonstrated that the PD-1 gene was a predisposing gene to the development of T1D mellitus in the Japanese population.

Infants with higher birthweight and/or greater weight gain during the first month of life may have a risk of being overweight at 3 years of age.