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Aims/Introduction We compared the results of testing for glutamic acid decarboxylase antibodies (GADAb) using a radioimmunoassay (RIA) and an enzyme‐linked immunosorbent assay (ELISA) in individuals with childhood‐onset type 1 diabetes mellitus. Materials and Methods Serum specimens were collected from 1,024 Japanese children (426 boys and 598 girls) in 2013. The median age at diagnosis was 7 years (0–18 years). The blood specimens were obtained at a median age of 13 years (2–22 years). Results Among the 628 children whose serum specimens were collected within 5 years after diagnosis, the rate of GADAb positivity was 47.9% using RIA and 69.4% using ELISA. The participants were divided into four groups according to their RIA and ELISA results for GADAb as follows: group I (RIA+/ELISA+), group II (RIA+/ELISA−), group III (RIA−/ELISA+) and group IV (RIA−/ELISA−). The clinical and genetic characteristics of group I and group III were quite similar in terms of age at diagnosis, male/female ratio, relatively high positive rates for both autoantibody to protein tyrosine phosphatase IA‐2 and autoantibody to the cation efflux transporter zinc transporter 8, and human leukocyte antigen genotype. Group II contained just five patients, and was characterized by a younger age at diagnosis, low positive rates for both autoantibody to protein tyrosine phosphatase IA‐2 and autoantibody to the cation efflux transporter zinc transporter 8, and a unique human leukocyte antigen genotype. If the positive rates of either autoantibody to protein tyrosine phosphatase IA‐2 or autoantibody to the cation efflux transporter zinc transporter 8 or both were added to the GADAb results using RIA, the percentage of autoimmune type 1 diabetes increased from 47.9% to 78.5%. Conclusions The diagnosis of autoimmune childhood‐onset Japanese type 1 diabetes increased when GADAb results were obtained using a new ELISA method, compared with a previously utilized RIA method., The diagnosis of autoimmune childhood‐onset Japanese type 1 diabetes was increased by the glutamic acid decarboxylase antibodies using a new enzyme‐linked immunosorbent assay in comparison with a previous radioimmunoassay.

Aims To evaluate comprehensively the use of the glycated albumin to HbA1c ratio for estimation of glycaemic control in the previous month. Methods A total of 306 children with Type 1 diabetes mellitus underwent ≥10 simultaneous measurements of glycated albumin and HbA1c . Correlation and concordance rates were examined between HbA1c measurements taken 1 month apart (ΔHbA1c ) and glycated albumin/HbA1c ratio fluctuations were calculated as Z-scores from the cohort value at enrolment of this study cohort (method A) or the percent difference from the individual mean over time (method B). Results Fluctuations in glycated albumin/HbA1c ratio (using both methods) were weakly but significantly correlated with ΔHbA1c , whereas concordance rates were significant for glycaemic deterioration but not for glycaemic improvement. Concordance rates were higher using method B than method A. Conclusions The glycated albumin/HbA1c ratio was able to estimate glycaemic deterioration in the previous month, while estimation of glycaemic improvement in the preceding month was limited. Because method B provided a better estimate of recent glycaemic control than method A, the individual mean of several measurements of the glycated albumin/HbA1c ratio over time may also identify individuals with high or low haemoglobin glycation phenotypes in a given population, such as Japanese children with Type 1 diabetes, thereby allowing more effective diabetes management.

Aims The aim of this study was to clarify the significance of previously reported susceptibility variants in the development of autoimmune Type 1 diabetes in non-white children. Tested variants included rs2290400, which has been linked to Type 1 diabetes only in one study on white people. Haplotypes at 17q12-q21 encompassing rs2290400 are known to determine the susceptibility of early-onset asthma by affecting the expression of flanking genes. Methods We genotyped 63 variants in 428 Japanese people with childhood-onset autoimmune Type 1 diabetes and 457 individuals without diabetes. Possible association between variants and age at diabetes onset was examined using age-specific quantitative trait locus analysis and ordered-subset regression analysis. Results Ten variants, including rs2290400 in GSDMB, were more frequent among the people with Type 1 diabetes than those without diabetes. Of these, rs689 in INS and rs231775 in CTLA4 yielded particularly high odds ratios of 5.58 (corrected P value 0.001; 95% CI 2.15–14.47) and 1.64 (corrected P value 5.3 × 10-5; 95% CI 1.34–2.01), respectively. Age-specific effects on diabetes susceptibility were suggested for rs2290400; heterozygosity of the risk alleles was associated with relatively early onset of diabetes, and the allele was linked to the phenotype exclusively in the subgroup of age at onset ≤ 5.0 years. Conclusions The results indicate that rs2290400 in GSDMB and polymorphisms in INS and CTLA4 are associated with the risk of Type 1 diabetes in Japanese children. Importantly, cis-regulatory haplotypes at 17q12-q21 encompassing rs2290400 probably determine the risk of autoimmune Type 1 diabetes predominantly in early childhood.

OBJECTIVE: The aim of this study was to examine plasma adiponectin concentrations during perinatal the period and their correlations with fetal anthropometric parameters and other hormones. DESIGN: Venous cord blood samples were obtained from 59 full-term healthy newborns (36 males and 23 females, gestational age 37.0-41.4 weeks, birth weight 2,146-4,326 g, birth length 44.0-54.5 cm). The blood samples were also obtained from 15 neonates (postnatal day 3-7) whose cord blood had already been collected and the changes in adiponectin concentrations were examined. MEASUREMENTS: The adiponectin concentration was determined by enzyme-linked immunosorbent assay. The leptin concentration was determined by radioimmunoassay. Insulin, GH and IGF-1 concentrations were determined by immunoradiometric assays. RESULTS: The plasma adiponectin concentrations in cord blood ranged from 6.0 to 55.8 microg/ml (median 22.4 microg/ml), which were much higher than those in normal-weight adults (P < 0.0001). In contrast to the findings in adults, these values were positively correlated with birth weight (r = 0.43, P = 0.0005), body mass index (r = 0.44, P = 0.0005), birth weight/birth length ratio (r = 0.46, P = 0.0002) and the leptin concentrations (r = 0.39, P = 0.004). When the effects of fat mass-related anthropometric parameters such as the birth weight/birth length ratio were controlled, plasma adiponectin concentrations had a significant inverse correlation with insulin concentrations (r = -0.35, P = 0.01). There was no significant gender difference in adiponectin concentrations among newborns. The adiponectin concentrations in neonates (postnatal day 3-7) did not change significantly compared with those in cord blood. CONCLUSIONS: In contrast to the findings in adults, these results suggest that the adiponectin concentration increases with the mass of fetal fat.

The twitcher mouse is well known as a naturally occurring authentic mouse model of human globoid cell leukodystrophy (GLD; Krabbe disease) due to genetic deficiency of lysosomal galactosylceramidase. The twitcher mice used most commonly are on the C57BL/6J background. We generated twitcher mice that were on the mixed background of C57BL/6J and 129SvEv, the standard strain for production of targeted mutations. Twitcher mice on the mixed background were smaller and had a shorter lifespan than were those on the C57BL/6J background. Many twitcher mice on the mixed background developed generalized seizures around 30 days that were never seen in twitcher mice on the C57BL/6J background. Neuropathologically, although the degree of the typical demyelination with infiltration of macrophages was similar in the central and peripheral nervous systems, in both strains, marked neuronal cell death was observed only in twitcher mice on the mixed background. In the hippocampus, the neuronal cell death occurred prominently in the CA3 region in contrast to the relatively well-preserved CA1 and CA2 areas. This neuropathology has never been seen in twitcher mice on the C57BL/6J background. Biochemically, the brain of twitcher mice on the mixed background showed much greater accumulation of lactosylceramide. Genetic background must be carefully taken into consideration when phenotype of mutant mice is evaluated, particularly because most targeted mutants are initially on a mixed genetic background and gradually moved to a pure background. These findings also suggest an intriguing possibility of important function of some sphingolipids in the hippocampal neuronal organization and maintenance.

Type II citrullinaemia (CTLN2) is an adult- or late childhood-onset liver disease characterized by a liver-specific defect in argininosuccinate synthetase protein. The enzyme abnormality is caused by deficiency of the protein citrin, which is encoded by the SLC25A 13 gene. Until now, however, few cases with SLC25A13 mutations have been reported in children with liver disease. We describe an infant who presented with neonatal hepatitis in association with hypergalactosaemia detected by neonatal mass screening. DNA analysis of SLC25A13 revealed that the patient was homozygous for a IVS11+1GA mutation. This case suggests that SLC25A13 mutant should be suspected in neonatal patients with hypergalactosaemia of unknown cause.

The diagnosis of pyruvate dehydrogenase (PDH) E1 alpha deficiency, which is an X-linked inborn error of metabolism, is usually established by the measurement of PDH complex activity in cultured cells. However, heterozygous female patients with PDH E1 alpha deficiency may be misdiagnosed when the normal X chromosome is predominantly expressed in the cultured cells. Therefore, in female patients with convincing clinical presentations of PDH E1 alpha deficiency and the normal enzyme activity, the X-inactivation pattern should be analysed and the PDH E1 alpha gene screened for mutations. For this screening, we applied the method of single-strand conformational polymorphism (SSCP) and DNA sequencing and examined 11 female patients with congenital lactic acidaemia whose PDH complex activity was normal in cultured cells. In 2 of the 11 female patients, we found distinct pathogenic missense mutations in the PDH E1 alpha gene (G89S and G291R). Both affected patients showed a similar clinical presentation and had been diagnosed as West syndrome. In 3 of the 11 patients, we found a polymorphic base-pair substitution in exon 9 of the PDH E1 alpha gene which resulted in a changed amino acid residue (M282L). We conclude that PCR-SSCP analysis of the PDH E1 alpha gene, followed by DNA sequencing, is a useful method to screen for mutations of the PDH E1 alpha gene in female patients with congenital lactic acidaemia who have normal enzyme activities in available samples, normal ratio of lactate to pyruvate, and predominantly raised lactate concentration in cerebrospinal fluid.

Vitamin D-dependent rickets type II is a rare disease caused by a disorder of the receptor for 1, 25-dihydroxyvitamin D (1, 25(OH)2D). Several parameters of this receptor-effector system were investigated to obtain biochemical information on the presumed heterozygotes of vitamin D-dependent rickets type II in parents of five patients and in their age-matched controls. It was found that the serum concentrations of 1, 25-(OH)2D and 24,25-dihydroxy-vitamin D (24,25(OH)2D), and the ratio of 1,25-(OH)2D/24,25-(OH)2D differed significantly in the parents from those of the patients and the respective control groups. In the parents' cultured skin fibroblasts, the activity of 25-hydroxyvitamin D-24-hydroxylase induced by 10(-8) mol/L 1, 25-(OH)2D3 ranged from 50 to 82% of that of their controls (versus 1-13% of controls for the patients). The binding capacity of the parents' [3H]1, 25-(OH)2D3 to the nucleus was 38-54% of that of their control subjects (versus 7-27% of controls for the patients). The parents' values were thus in a range between those of the patients and the control groups. These findings suggest that, in the parents, a partial impairment of the receptor system for 1, 25-(OH)2D led to an imbalance of vitamin D metabolism, thus confirming that vitamin D-dependent rickets type II is an autosomal recessive inherited disease. Serum concentrations of 1, 25-(OH)2D and 24, 25-(OH)2D may provide useful parameters for detecting heterozygotes of this disease.

To explore the relationship between ribonucleotide reductase and immunodysfunction in adenosine deaminase deficiency, the effects of deoxyadenosine on ribonucleotide reductase in ADA-deficient lymphocytes was investigated. An assay system for ribonucleotide reductase in intact permeabilized lymphocytes was developed to approximate physiological conditions. The activity of cytidine diphosphate (CDP) reductase in resting but not in proliferating lymphocytes in culture was inhibited by 1 to 10 mumol/L deoxyadenosine. The resting cells were protected from the toxicity of 1 mumol/L deoxyadenosine by 5 mmol/L nicotinamide or 30 mumol/L deoxycytidine and from that of 10 mumol/L deoxyadenosine by 30 mumol/L deoxycytidine. These findings suggest that depletion of nicotinamide adenine dinucleotide might be the principal cause of death in resting lymphocytes with ADA deficiency. It is concluded that the mechanism of deoxyadenosine toxicity on non-replicating lymphocytes, which may not be mediated by ribonucleotide reductase inhibition, is closely related to the mechanism of immunodysfunction in patients with ADA deficiency.