Incidence of childhood type 1 diabetes mellitus in Yamanashi Prefecture, Japan, 1986-2018

Introduction

Several studies have examined the incidence of childhood T1DM in Japan from the 1970s onwards, but none have been long-term studies using registration data. We estimate the incidence of childhood type 1 diabetes mellitus (T1DM) from 1986 to 2018 in Yamanashi Prefecture, Japan.

Methods

We began a population-based, long-term study of childhood T1DM in 1986 involving every hospital paediatrics department in Yamanashi Prefecture. In the Prefecture, every child newly diagnosed with T1DM is referred to a hospital, and therefore, almost 100% of new patients aged <15 years are registered. We calculated the incidence of T1DM among children aged <15 years from 1986 to 2018. All cases met the Japan Diabetes Society diagnostic criteria and were tested for T1DM-related autoantibodies whenever possible.

Results

Ninety-nine patients (44 boys and 55 girls) were newly diagnosed with T1DM. The annual incidence among 5- to 9-year-olds increased by 5.35% over the study period (95% confidence interval 2.34%-8.35%, p = .0005), and there was a trend towards increasing 3-year incidence (15.52% increase, p = .0516). There were also trends towards increasing annual and 3-year incidence among 0- to 14-year-olds. However, there were no changes over time in annual or 3-year incidence in the 0-4 year or 10-14 year age groups.

Conclusions

The incidence of T1DM in Yamanashi Prefecture increased among children aged 0-14 years over the study period, with the most significant increase occurring among 5- to 9-year-olds. These data suggest that the number of children aged <15 years with T1DM is gradually increasing in one of the local prefectures in Japan, Yamanashi Prefecture and that the age of onset is decreasing.

Residual endogenous insulin secretion in Japanese children with type 1A diabetes

We investigated serum C-peptide immunoreactivity (CPR) levels in registered data from a multi-center collaborative nationwide type 1 diabetes study. The CPR levels were obtained from 576 and 409 children during the early registration (2013/2014) and late observation (2016/2017) periods, respectively. The percentages of children with a CPR < 0.1 or < 0.3 ng/mL increased according to the duration since diagnosis. Among patients with 5 or more years since diagnosis, 69% had a CPR < 0.1 and 95% had a CPR < 0.3 in the early registration period. A significant negative correlation was observed between the HbA1c and the CPR levels, and the HbA1c levels were significantly higher among children with a CPR < 0.1 or < 0.3 than among those with a CPR ≥ 0.6 ng/mL. During the late observation period, the prevalence of a CPR < 0.1 ng/mL was 88% among long-standing patients and 77% among patients aged 18–20 yr. Regarding the characteristics of “Responders” with a sustained CPR ≥ 0.6 ng/mL at 5 or more years since diagnosis, six of the seven were adolescent females; five of the seven had an HLA DR4-DQ4 haplotype. When type 1A diabetes mellitus (T1AD) children transit to adult care centers, most of them may have some difficulty in glycemic control because of the depleted endogenous insulin.

Low prevalence of maternal microchimerism in peripheral blood of Japanese children with type 1 diabetes

AIM

To clarify the prevalence and degree of maternal microchimerism in Japanese children with type 1 diabetes, as well as its effect on phenotypic variation.

METHODS

We studied 153 Japanese children with type 1 diabetes, including 124 children positive for β-cell autoantibodies, and their 71 unaffected siblings. The number of circulating microchimeric cells per 10⁵ host cells was estimated by the use of quantitative-polymerase chain reaction targeting non-transmitted maternal human leukocyte antigen alleles. The results were compared to previous data from white European people. Phenotypic comparison was performed between maternal microchimerism carriers and non-carriers with diabetes.

RESULTS

Maternal microchimerism was detected in 15% of children with autoantibody-positive type 1 diabetes, 28% of children with autoantibody-negative type 1 diabetes, and 16% of unaffected siblings. There were no differences in the prevalence or levels of maternal microchimerism among the three groups or between the children with type 1 diabetes and their unaffected siblings. Furthermore, maternal microchimerism carriers and non-carriers exhibited similar phenotypes.

CONCLUSIONS

Maternal microchimerism appears to be less common in Japanese children with type 1 diabetes than in white European people. Our data indicate that maternal microchimerism is unlikely to be a major trigger or a phenotypic determinant of type 1 diabetes in Japanese children and that the biological significance of maternal microchimerism in type 1 diabetes may differ among ethnic groups.

Increasing secular trends in height and obesity in children with type 1 diabetes: JSGIT cohort

BACKGROUND

Recently, anthropometric indices in children with type 1 diabetes mellitus (T1DM) have begun to change.

OBJECTIVE

To examine secular trends in patients' anthropometric indices.

SUBJECTS

Japanese children with T1DM from the 1995, 2000, 2008 and 2013 cohorts of The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes.

METHODS

We analysed serum haemoglobin A1c (HbA1c) levels, the incidence of severe hypoglycaemic events, the types and doses of insulin, height standard deviation scores (SDS), body mass index (BMI) percentiles compared with healthy Japanese children and obesity prevalence over time. We also stratified the patients according to glycaemic control levels of <58 mmol/mol (optimal), 58-75 mmol/mol (suboptimal) and ≥75 mmol/mol (high-risk).

RESULTS

Data for 513-978 patients from each of the cohorts were analysed. The incidence of severe hypoglycaemic events decreased over time (from 21 to 4.8/100 patient-years), while the proportion of insulin analogue doses increased (14.6% to 98.6%). In addition, patient height SDS (-0.22 to +0.17), BMI percentile (52.1 to 58.7) and obesity prevalence (2.1% to 5.1%) increased. Height SDS increased in all of the glycaemic control subgroups, while BMI percentile and obesity prevalence increased in the suboptimal and high-risk groups.

CONCLUSIONS

Since 1995, the average height of children with T1DM has increased in parallel with increasing insulin doses. Clinicians should be aware of increased BMI in these patients and the associated risk of developing cardiovascular disease in the future.

MRI Findings of Immune Checkpoint Inhibitor-Induced Hypophysitis: Possible Association with Fibrosis

BACKGROUND AND PURPOSE

Hypophysitis is one of the well-known adverse effects of immune checkpoint inhibitors. Immune checkpoint inhibitor-induced hypophysitis frequently causes irreversible hypopituitarism, which requires long-term hormone replacement. Despite the high frequency and clinical significance, characteristic MR imaging findings of immune checkpoint inhibitor-induced hypophysitis have not been established. In the present study, we aimed to review and extract the MR imaging features of immune checkpoint inhibitor-induced hypophysitis.

MATERIALS AND METHODS

This retrospective international multicenter study comprised 20 patients with melanoma who were being treated with immune checkpoint inhibitors and clinically diagnosed with immune checkpoint inhibitor-induced hypophysitis. Three radiologists evaluated the following MR imaging findings: enlargement of the pituitary gland and stalk; homogeneity of enhancement of the pituitary gland; presence/absence of a well-defined poorly enhanced area and, if present, its location, shape, and signal intensity in T2WI; and enhancement pattern in contrast-enhanced dynamic MR imaging. Clinical symptoms and hormone levels were also recorded.

RESULTS

Enlargement of the pituitary gland and stalk was observed in 12 and 20 patients, respectively. Nineteen patients showed poorly enhanced lesions (geographic hypoenhancing lesions) in the anterior lobe, and 11 of these lesions showed hypointensity on T2WI. Thyrotropin deficiency and corticotropin deficiency were observed in 19/20 and 12/17 patients, respectively, which persisted in 12/19 and 10/12 patients, respectively, throughout the study period.

CONCLUSIONS

Pituitary geographic hypoenhancing lesions in the anterior lobe of the pituitary gland are characteristic and frequent MR imaging findings of immune checkpoint inhibitor-induced hypophysitis. They reflect fibrosis and are useful in distinguishing immune checkpoint inhibitor-induced hypophysitis from other types of hypophysitis/tumors.

Increased diagnosis of autoimmune childhood-onset Japanese type 1 diabetes using a new glutamic acid decarboxylase antibody enzyme-linked immunosorbent assay kit, compared with a previously used glutamic acid decarboxylase antibody radioimmunoassay kit

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.

Status and trends in the use of insulin analogs, insulin delivery systems and their association with glycemic control: comparison of the two consecutive recent cohorts of Japanese children and adolescents with type 1 diabetes mellitus

Background Treatment for type 1 diabetes mellitus (T1DM) has greatly changed by the general use of insulin analogs and continuous subcutaneous insulin infusion (CSII). To investigate whether these advances have been translated into continued improvement in glycemic control in Japanese children and adolescents, we analyzed the registration data of the two consecutive recent cohorts of Japanese childhood-onset T1DM patients. Methods The registration data including hemoglobin A1c (HbA1c), hypoglycemia and insulin regimen were compared between the two cohorts (862 patients in the 2008 cohort and 1090 in the 2013 cohort). Results The proportion of subjects with multiple daily insulin injection therapy (MDI) and CSII significantly increased (p<0.0001) from 67.4% and 9.7% to 71.8% and 23.4%, respectively. In the 2013 cohort, almost all patients were treated with basal-bolus treatment using insulin analogs. The use of CSII increased in all age groups, especially in the age group 0-5 years. The rates of overall, moderate and severe hypoglycemia significantly declined from 10.24, 10.18 and 0.056 events/100 persons/period in the 2008 cohort to 0.66, 0.62 and 0.033 in the 2013 cohort (p<0.0001, <0.0001, 0.04), respectively. Contrarily, there were no significant changes in HbA1c values between the two cohorts. Conclusions The popularization of the basal-bolus treatment using insulin analogs hascontributed to a significant decrease in hypoglycemia. In contrast, the intensive insulin treatment may not be enough for the satisfactory improvement of glycemic control in Japanese children and adolescents with T1DM. Considerable points remain, such as diabetic education and support to motivate patients.

Fulminant type 1 diabetes mellitus in Japanese children and adolescents: multi-institutional joint research of the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes

Fulminant type 1 diabetes mellitus (FT1DM) is a subtype of type 1 diabetes mellitus characterized by a remarkably abrupt onset. In Japan, FT1DM accounts for approximately 20% of acute-onset adult type 1 diabetes mellitus cases; however, reports of pediatric-onset FT1DM are rare. We aimed to determine the frequency and clinical characteristics of FT1DM in Japanese children and adolescents by conducting a 2-phase questionnaire survey among the members of the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) regarding their clinical experience with FT1DM. Responses were obtained from 54 of the 79 participating hospitals (68.4%). Of these, 8 hospitals managed a total of 15 pediatric patients with FT1DM (4 patients in each of 2 hospitals, 2 patients in 1 hospital, and 1 patient in each of 5 hospitals). The distribution of patient age was biphasic, with peaks in children younger than 5 years and older than 8 years of age. The clinical characteristics of FT1DM in this population (such as the duration from onset of symptoms to diagnosis, severity of symptoms, preceding flu-like episodes, and abnormal laboratory data) did not differ from those of patients with adult-onset FT1DM. The frequency of pediatric-onset FT1DM is low compared with that of adult-onset FT1DM. The genetic background and susceptibility patterns of pediatric patients with FT1DM may differ from those typical of adults with FT1DM, but both age groups share similar clinical characteristics.

Estimation of glycaemic control in the past month using ratio of glycated albumin to HbA1c

AIMS

To evaluate comprehensively the use of the glycated albumin to HbA_1c 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 HbA_1c . Correlation and concordance rates were examined between HbA_1c measurements taken 1 month apart (ΔHbA_1c ) and glycated albumin/HbA_1c 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/HbA_1c ratio (using both methods) were weakly but significantly correlated with ΔHbA_1c , 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/HbA_1c 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/HbA_1c 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.

Protein-altering variants of PTPN2 in childhood-onset Type 1A diabetes

AIM

To examine the contribution of PTPN2 coding variants to the risk of childhood-onset Type 1A diabetes.

METHODS

PTPN2 mutation analysis was carried out for 169 unrelated Japanese people with childhood-onset Type 1A diabetes. We searched for coding variants that were absent or extremely rare in the general population and were scored as damaging by multiple in silico programs. We performed mRNA analysis and three-dimensional structural prediction of the detected variants, when possible. We also examined possible physical links between these variants and previously reported risk SNPs as well as clinical information from variant-positive children.

RESULTS

One frameshift variant (p.Q286Yfs*24) and two probably damaging missense substitutions (p.C232W and p.R350Q) were identified in one child each. Of these, p.Q286Yfs*24 and p.C232W were hitherto unreported, while p.R350Q accounted for 2/121,122 alleles of the exome datasets. The p.Q286Yfs*24 variant did not encode stable mRNA, and p.C232W appeared to affect the structure of the tyrosine-protein phosphatase domain. The three variants were physically unrelated to known risk SNPs. The variant-positive children manifested Type 1A diabetes without additional clinical features and invariably carried risk human leukocyte antigen alleles.

CONCLUSIONS

The results provide the first indication that PTPN2 variants contribute to the risk of Type 1A diabetes, independently of known risk SNPs. PTPN2 coding variants possibly induce non-specific Type 1A diabetes phenotypes in individuals with human leukocyte antigen-mediated disease susceptibility. Our findings warrant further validation.

Comprehensive screening for monogenic diabetes in 89 Japanese children with insulin-requiring antibody-negative type 1 diabetes

BACKGROUND

Mutations in causative genes for neonatal diabetes or maturity-onset diabetes of the young have been identified in multiple patients with autoantibody-negative type 1 diabetes (T1D).

OBJECTIVES

We aimed to clarify the prevalence and phenotypic characteristics of monogenic abnormalities among 89 children with autoantibody-negative insulin-requiring T1D.

METHODS

Mutations in 30 genes were screened using next-generation sequencing, and copy-number alterations of 4 major causative genes were examined using multiplex-ligation-dependent probe amplification. We compared the clinical characteristics between mutation carriers and non-carriers.

RESULTS

We identified 11 probable pathogenic substitutions (6 in INS , 2 in HNF1A , 2 in HNF4A , and 1 in HNF1B ) in 11 cases, but no copy-number abnormalities. Only 2 mutation carriers had affected parents. De novo occurrence was confirmed for 3 mutations. The non-carrier group, but not the carrier group, was enriched with susceptible HLA alleles. Mutation carriers exhibited comparable phenotypes to those of non-carriers, except for a relatively normal body mass index (BMI) at diagnosis.

CONCLUSIONS

This study demonstrated significant genetic overlap between autoantibody-negative T1D and monogenic diabetes. Mutations in INS and HNF genes, but not those in GCK and other monogenic diabetes genes, likely play critical roles in children with insulin-requiring T1D. This study also suggests the relatively high de novo rates of INS and HNF mutations, and the etiological link between autoimmune abnormalities and T1D in the non-carrier group. Carriers of monogenic mutations show non-specific phenotypes among all T1D cases, although they are more likely to have a normal BMI at diagnosis than non-carriers.

Improvement in glycemic control through changes in insulin regimens: findings from a Japanese cohort of children and adolescents with type 1 diabetes

OBJECTIVE

Although insulin analogs have dramatically changed diabetes treatment, scarce evidence is available on those effects. We aimed to explore whether glycemic control had improved, the use of insulin analogs had been increased, and hypoglycemic events had decreased over time in Japanese pediatric patients with type 1 diabetes (T1D).

METHODS

Glycated hemoglobin A1c (HbA1c) values, proportion of insulin regimens, incidence of severe hypoglycemic events, and pubertal increase in HbA1c were compared in three cohorts of childhood-onset Japanese T1D patients (567 subjects in the 1995 cohort, 754 subjects in the 2000 cohort, and 806 subjects in the 2008 cohort).

RESULTS

Mean HbA1c values tended to decrease [78.5 mmol/mol (9.33%) in the 1995 cohort, 68.2 mmol/mol (8.39%) in the 2000 cohort, and 61.2 mmol/mol (7.75%) in the 2008 cohort; P < .0001]. The proportion of patients who received basal-bolus treatment tended to increase with statistical significance, as did the proportion on insulin analogs. The incidence of severe hypoglycemic events (events/100 patients/y) had decreased (19.1 in the 2000 cohort and 8.7 in the 2008 cohort; P = .02). The pubertal increase in HbA1c tended to decrease [males, 12.0 mmol/mol (1.10%) in 1995, 9.4 mmol/mol (0.85%) in 2008, and 9.4 mmol/mol (0.86%) in 2008; P = .55; females, 14.0 mmol/mol (1.28%) in 1995, 10.3 mmol/mol (0.94%) in 2000, and 4.2 mmol/mol (0.38%) in 2008; P = .0003].

CONCLUSIONS

Glycemic control and incidence of severe hypoglycemic events were chronologically improved, especially in female adolescents.

FUT2 non-secretor status is associated with Type 1 diabetes susceptibility in Japanese children

AIM

To examine the contribution of the FUT2 gene and ABO blood type to the development of Type 1 diabetes in Japanese children.

METHODS

We analysed FUT2 variants and ABO genotypes in a total of 531 Japanese children diagnosed with Type 1 diabetes and 448 control subjects. The possible association of FUT2 variants and ABO genotypes with the onset of Type 1 diabetes was statistically examined.

RESULTS

The se2 genotype (c.385A>T) of the FUT2 gene was found to confer susceptibility to Type 1A diabetes in a recessive effects model [odds ratio for se2/se2, 1.68 (95% CI 1.20-2.35); corrected P value = 0.0075].

CONCLUSIONS

The FUT2 gene contributed to the development of Type 1 diabetes in the present cohort of Japanese children.

High-dose Cepharanthin for pediatric chronic immune thrombocytopenia in Japan

BACKGROUND

A nationwide, multicenter and observational study was retrospectively conducted to evaluate the clinical utility of Cepharanthin (CEP) for pediatric patients with chronic immune thrombocytopenia (ITP).

METHODS

Clinical and laboratory data for 46 Japanese patients aged <16 years who were diagnosed as having chronic ITP in 14 hospitals during 2001-2011, and were treated with CEP for >12 months, were analyzed.

RESULTS

Median daily CEP dose was 1 mg/kg (range, 0.12-2 mg/kg). Median platelet count prior to CEP was 20.5 × 10⁹ /L (IQR, 8.3-53.0 × 10⁹ /L), and then significantly increased to 58.5 × 10⁹ /L (IQR, 22.8-115.0 × 10⁹ /L) and 69.0 × 10⁹ /L (IQR, 23.0-134.0 × 10⁹ /L) at 12 and 24 months of treatment, respectively. No life-threatening bleeds or moderate-severe adverse events were reported. Of 38 patients who received both corticosteroids (CS) and CEP, 17 patients (45%) were weaned from CS, and 15 patients (39%) attained the reduced dose of CS. The duration from the start of CEP to the stopping of CS was a median of 413 days (range, 49-1734 days) in patients who were weaned from CS.

CONCLUSIONS

CEP alone or combined with CS was useful for the management of pediatric chronic ITPs.

Variants associated with autoimmune Type 1 diabetes in Japanese children: implications for age-specific effects of cis-regulatory haplotypes at 17q12-q21

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.

Nucleotide substitutions in CD101, the human homolog of a diabetes susceptibility gene in non-obese diabetic mouse, in patients with type 1 diabetes

Aims/Introduction

Although genome‐wide association studies have identified more than 50 susceptibility genes for type 1 diabetes, low‐frequency risk variants could remain unrecognized. The present study aimed to identify novel type 1 diabetes susceptibility genes by newly established methods.

Materials and Methods

We carried out whole‐exome sequencing and genome‐wide copy‐number analysis for a Japanese family consisting of two patients with type 1 diabetes and three unaffected relatives. Further mutation screening was carried out for 127 sporadic cases. The functional consequences of identified substitutions were evaluated by in silico analyses and fluorescence‐activated cell sorting of blood samples.

Results

Whole‐exome sequencing and genome‐wide copy‐number analysis of familial cases showed co‐segregation of the p.V863L substitution in CD101, the human homolog of an autoimmune diabetes gene in the non‐obese diabetic mouse, with type 1 diabetes. Mutation screening of CD101 in 127 sporadic cases detected the p.V678L and p.T944R substitutions in two patients. The p.V863L, p.V678L and p.T944R substitutions were absent or extremely rare in the general population, and were assessed as ‘probably/possibly damaging’ by in silico analyses. CD101 expression on monocytes, granulocytes and myeloid dendritic cells of mutation‐positive patients was weaker than that of control individuals.

Conclusions

These results raise the possibility that CD101 is a susceptibility gene for type 1 diabetes.

Identification of monogenic gene mutations in Japanese subjects diagnosed with type 1B diabetes between >5 and 15.1 years of age

BACKGROUND

Monogenic mutations, such as those in the potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11) and insulin (INS) genes, are identified in young patients with type 1B diabetes (non-autoimmune-mediated). We recently reported the results of a test for monogenic forms of diabetes in Japanese children who were diagnosed with type 1B diabetes at <5 years of age. In this study, we tested for monogenic forms of diabetes in Japanese children aged >5 to ≤15.1 years at the diagnosis of type 1B diabetes.

METHODS

Thirty-two Japanese children (eight males, 24 females) with type 1 diabetes negative for glutamate decarboxylase (GAD) 65 and/or IA-2A autoantibodies and who were aged >5 to 15.1 years at diagnosis were recruited from 16 independent hospitals participating in the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT). We performed mutational analyses of genes with a high frequency of mutation [INS, KCNJ11, hepatocyte nuclear factor 1 alpha (HNF1α) and hepatocyte nuclear factor 4 alpha (HNF4α)].

RESULTS

We identified one missense mutation (G32S) in the INS gene and two mutations (R131Q and R203S) in the HNF1α gene that could be associated with diabetes. No missense change was found in the KCNJ11 gene.

CONCLUSIONS

Our results suggest that although mutations in the INS gene can be detected in Japanese patients aged >5 years at diagnosis, the frequency of mutations decrease in older age groups. Conversely, the frequency of the mutation in the HNF1α gene increased in patients diagnosed at age 5 or older. Clinicians should consider the possibility of maturity onset diabetes of the young (MODY) in children diagnosed with type 1B diabetes.

[Childhood and adolescent diabetes in Japan]

The glycemic control in Japanese children and adolescents with type 1 diabetes has been improved with emphasis on increase in target level of HbA1c<7.5% and decrease in risk level ≥ 9%. It may be due to increase the basal-bolus insulin therapy in almost all patients across ages, especially pubertal ages, following the use of rapid acting insulin analogues and long-acting analogues. Regarding to type 2 diabetes, little improvement has been observed because of the lack of enough skill to guide. The interruption of therapy or visiting medical resources may be a big burden. Monogenic diabetes has been more frequently found from previously diagnosed type 1B diabetes and type 2 diabetes. MODY genes can be noticed in children from urine-screening program, with the history of low-birth weight, even not having family history of diabetes and so on.

Treatment situation of male hypogonadotropic hypogonadism in pediatrics and proposal of testosterone and gonadotropins replacement therapy protocols

Male hypogonadotropic hypogonadism (MHH), a disorder associated with infertility, is treated with testosterone replacement therapy (TRT) and/or gonadotropins replacement therapy (GRT) (TRT and GRT, together with HRT hormone replacement therapy). In Japan, guidelines have been set for treatment during adolescence. Due to the risk of rapid maturation of bone age, low doses of testosterone or gonadotropins have been used. However, the optimal timing and methods of therapeutic intervention have not yet been established. The objective of this study was to investigate the current situation of treatment for children with MHH in Japan and to review a primary survey involving councilors of the Japanese Society for Pediatric Endocrinology and a secondary survey obtained from 26 facilities conducting HRT. The subjects were 55 patients with MHH who reached their adult height after HRT. The breakdown of the patients is as follows: 7 patients with Kallmann syndrome, 6 patients with isolated gonadotropin deficiency, 18 patients with acquired hypopituitarism due to intracranial and pituitary tumor, 22 patients with classical idiopathic hypopituitarism due to breech delivery, and 2 patients with CHARGE syndrome. The mean age at the start of HRT was 15.7 yrs and mean height was 157.2 cm. The mean age at reaching adult height was 19.4 yrs, and the mean adult height was 171.0 cm. The starting age of HRT was later than the normal pubertal age and showed a significant negative correlation with pubertal height gain, but it showed no correlation with adult height. As for spermatogenesis, 76% of the above patients treated with hCG-rFSH combined therapy showed positive results, though ranging in levels; impaired spermatogenesis was observed in some with congenital MHH, and favorable spermatogenesis was observed in all with acquired MHH. From the above, we propose the establishment of a treatment protocol for the start low-dose testosterone or low-dose gonadotropins by dividing subjects into two groups to determine different treatment protocols, acquired and congenital MHH, and to conduct them at a timing closer to the onset of puberty, namely, at a timing near entrance to junior high school. We also propose a new HRT protocol using preemptive FSH therapy prior to GRT aimed at achieving future fertility in patients with congenital MHH.

The ratio of glycated albumin to hemoglobin A1c measured in IFCC units accurately represents the glycation gap

The glycation gap (G-gap: difference between measured hemoglobin A1c [A1C] and the value predicted by its regression on the fructosamine level) is stable and associated with diabetic complications. Measuring A1C level in International Federation of Clinical Chemistry (IFCC) units (A1C-SI; mmol/mol) and National Glycohemoglobin Standardization Program units (A1C-NGSP; %) and using glycated albumin (GA) level instead of fructosamine level for calculating the G-gap, we investigated whether the G-gap is better represented by GA/A1C ratio if expressed in SI units (GA/A1C-SI ratio) rather than in NGSP units (GA/A1C-% ratio). We examined 749 Japanese children with type 1 diabetes using simultaneous GA and A1C measurements. Of these, 369 patients were examined more than five times to assess the consistency of the G-gap and the GA/A1C ratio within individuals. The relationship of GA/A1C-% ratio to the corresponding A1C-NGSP was stronger than that of GA/A1C-SI ratio to A1C-IFCC. At enrollment, the inverse relationship between the GA/A1C-SI ratio and G-gap was highly significant (R(2) = 0.95) compared with that between the GA/A1C-% ratio and G-gap (R(2) = 0.69). A highly significant inverse relationship was also observed between the mean GA/A1C-SI ratio and the mean G-gaps obtained individually over time (R(2) = 0.95) compared with that using the corresponding A1C-NGSP (R(2) = 0.67). We conclude that the G-gap is better represented by the GA/A1C-SI ratio. We propose the use of mean GA/A1C-SI ratios easily obtained individually over time as reference values in Japanese children with type 1 diabetes (6.75 ± 0.60 [means ± SD]).

Molecular diagnosis of mitochondrial respiratory chain disorders in Japan: focusing on mitochondrial DNA depletion syndrome

BACKGROUND

Although mitochondrial respiratory chain disorders (MRCD) are one of the most common congenital metabolic diseases, there is no cumulative data on enzymatic diagnosis and clinical manifestation for MRCD in Japan and Asia.

METHODS

We evaluated 675 Japanese patients having profound lactic acidemia, or patients having symptoms or signs of multiple-organ origin simultaneously without lactic acidemia on respiratory chain enzyme activity assay and blue native polyacrylamide gel electrophoresis. Quantitative polymerase chain reaction was used to diagnose mitochondrial DNA depletion syndrome (MTDPS). Mutation analysis of several genes responsible for MTDPS was also performed.

RESULTS

A total of 232 patients were diagnosed with a probable or definite MRCD. MRCD are common, afflicting one in every several thousand people in Japan. More than one in 10 of the patients diagnosed lacked lactic acidemia. A subsequent analysis of the causative genes of MTDPS identified novel mutations in six of the patients. A 335 bp deletion in deoxyguanosine kinase (DGUOK; g.11692_12026del335 (p.A48fsX90)) was noted in two unrelated families, and may therefore be a common mutation in Japanese people. The proportion of all patients with MTDPS, and particularly those with recessive DNA polymerase γ (POLG) mutations, appears to be lower in Japan than in other studies. This is most likely due to the relatively high prevalence of ancient European POLG mutations in Caucasian populations. No other significant differences were identified in a comparison of the enzymatic diagnoses, disease classifications or prognoses in Japanese and Caucasian patients with MRCD.

CONCLUSION

MTDPS and other MRCD are common, but serious, diseases that occur across all races.

Noradrenergic modulation of vicarious trial-and-error behavior during a spatial decision-making task in rats

Deliberation between possible options before making a decision is crucial to responding with an optimal choice. However, the neural mechanisms regulating this deliberative decision-making process are still unclear. Recent studies have proposed that the locus coeruleus-noradrenaline (LC-NA) system plays a role in attention, behavioral flexibility, and exploration, which contribute to the search for an optimal choice under uncertain situations. In the present study, we examined whether the LC-NA system relates to the deliberative process in a T-maze spatial decision-making task in rats. To quantify deliberation in rats, we recorded vicarious trial-and-error behavior (VTE), which is considered to reflect a deliberative process exploring optimal choices. In experiment 1, we manipulated the difficulty of choice by varying the amount of reward pellets between the two maze arms (0 vs. 4, 1 vs. 3, 2 vs. 2). A difficulty-dependent increase in VTE was accompanied by a reduction of choice bias toward the high reward arm and an increase in time required to select one of the two arms in the more difficult manipulation. In addition, the increase of c-Fos-positive NA neurons in the LC depended on the task difficulty and the amount of c-Fos expression in LC-NA neurons positively correlated with the occurrence of VTE. In experiment 2, we inhibited LC-NA activity by injection of clonidine, an agonist of the alpha2 autoreceptor, during a decision-making task (1 vs. 3). The clonidine injection suppressed occurrence of VTE in the early phase of the task and subsequently impaired a valuable choice later in the task. These results suggest that the LC-NA system regulates the deliberative process during decision-making.

[The worldwide standardization of hemoglobin A1c measurement: the current statement from the Japan Diabetes Society and the issues to be solved]

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) have recently decided to use both units in the hemoglobin A1c (HbA1c) measurement based on the NGSP (previously called the National Glycohemoglobin Standardization Program) and the IFCC (International Federation of Clinical Chemistry) in articles and scientific meetings, whereas each country or region may use either NGSP units (conventional %) or IFCC units (SI; mmol/mol) in common practice. This is expressed as "a new twist on the path to harmony" in the measurement of HbA1c. Accordingly, the Japan Diabetes Society has used only NGSP units as of April 1, 2013, whereas the previous JDS units will be used for the high reproducibility of the JDS Standardization System but not in the clinical setting. JDS units are converted to NGSP units using JDS lots in Japan. Unfortunately however, there are significant differences between NGSP values obtained by the previously reported IFCC-JDS equations and those currently available in Japan. Therefore, this paper argues that IFCC units as the only valid anchor for scientific standardization should seek robust master equations for NGSP and JDS units. Furthermore, the biological variability of HbAlc, such as the Hemoglobin Glycation Index and the Glycation Gap, may be accurately evaluated by IFCC units because the values do not include additional factors such as non-glycated Hb in JDS and NGSP units.

Identification of INS and KCNJ11 gene mutations in type 1B diabetes in Japanese children with onset of diabetes before 5 years of age

BACKGROUND

The etiology of type 1 diabetes (T1D) is heterogeneous and is according to presence or absence of pancreatic autoantibodies divided into two subtypes: type 1A (autoimmune-mediated) and type 1B (non-autoimmune-mediated). Although several genes have been linked to type 1A diabetes, the genetic cause of type 1B diabetes in Japanese individuals is far from understood.

OBJECTIVE

The aim of this study was to test for monogenic forms of diabetes in auto antibody-negative Japanese children with T1D.

METHODS

Thirty four (19 males and 15 female) unrelated Japanese children with glutamate decarboxylase (GAD) 65 antibodies and/or IA-2A-negative T1D and diabetes diagnosed at < 5 yr of age were recruited from 17 unrelated hospitals participating in the Japanese Study Group of Insulin Therapy for children and adolescent diabetes (JSGIT). We screened the INS gene and the KCNJ11 gene which encode the ATP-sensitive potassium cannel by direct sequencing in 34 Japanese children with T1D.

RESULTS

We identified three novel (C31Y, C96R, and C109F) mutations and one previously reported mutation (R89C) in the INS gene in five children, in addition to one mutation in the KCNJ11 gene (H46R) in one child. These mutations are most likely pathogenic and therefore the cause of diabetes in carriers.

CONCLUSION

Our results suggest that monogenic forms of diabetes, particularly INS gene mutations, can be detected in Japanese patients classified with type 1B. Mutation screening, at least of the INS gene, is recommended for Japanese patients diagnosed as autoantibody negative at <5 yr of age.

Usefulness of insulin detemir in Japanese children with type 1 diabetes

BACKGROUND

This multicenter observational study was conducted to investigate the efficacy and safety of insulin detemir (detemir) for diabetes management in Japanese children and adolescents.

METHODS

Data from the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes database were analyzed. Ninety children (32 boys, 58 girls; mean age, 11.9 ± 3.8 years) who transferred from a neutral protamine Hagedorn insulin or insulin glargine basal-bolus regimen to detemir basal-bolus therapy and who were observed for at least 12 months were identified. Clinical data obtained at 0, 3, 6, and 12 months were analyzed to determine the type of bolus insulin used, number and timing of detemir injections, detemir dose as a proportion of the total insulin dose, hemoglobin A1c (HbA1c), fasting blood glucose (FBG) and frequency of severe hypoglycemia.

RESULTS

Twelve months after switching to detemir, the detemir dose represented 39.8% of the total insulin dose, and 37.8% of patients were being treated with twice-daily injections. HbA1c and FBG were significantly reduced from baseline at 3 and 6 months but not at 12 months. Considering the seasonal HbA1c variation in the Japanese population, a separate analysis was performed using data for 65 children (21 boys, 44 girls; mean age, 11.6 ± 2.9 years) who switched to detemir during the winter. Subset analysis showed significant HbA1c reductions from baseline at all specified times. The incidence of severe hypoglycemia during detemir treatment was 4.4 episodes per 100 patient-years.

CONCLUSIONS

Detemir is an effective and safe basal insulin for diabetes management in Japanese children and adolescents.

Screening and treatment of childhood type 1 and type 2 diabetes mellitus in Japan

A large number of children with type 2 diabetes mellitus (T2DM) and a small number with a slowly progressive form of type 1 diabetes mellitus (SPT1DM) have been detected by a urine glucose screening program conducted at Japanese schools since 1974. The incidence of T2DM in children has increased over the last 3 decades and is estimated to be approximately 3.0/100,000/year, which is twice as that of T1DM. In contrast, SPT1DM in children is more prevalent in Asians, particularly Japanese, and exhibits unique clinical features that differ from those of the rapid onset form of T1DM, usually seen in Caucasians. In the first part of this review, we summarize the urine glucose screening program conducted at Japanese schools and clinical characteristics of the 2 diabetic subtypes in Japanese children. In recent years, concerns regarding childhood diabetes in Asian countries, including Japan, have risen, and medical care for the same is exceedingly developing. Intensive insulin therapy such as basal-bolus therapy by multiple daily insulin injections and pump therapy, both using insulin analogs, has been increasing in pediatric patients with T1DM. In addition, various antidiabetic medications have been introduced for children with T2DM. In the second part of this review, we describe treatment of Japanese children with T1DM and T2DM and changes in glycemic control as a result of development of the treatment.

A Dual Reporter Splicing Assay Using HaloTag-containing Proteins

To evaluate the effects of genetic variations on mRNA splicing, we developed a minigene-based splicing assay using reporter genes encoding luciferase and the multifunctional HaloTag protein. In addition to conventional RT-PCR analysis, splicing events can be monitored in this system using two parameters: luciferase activity and signals derived from HaloTag-containing proteins bound to a fluorescent ligand following SDS-PAGE. The luciferase activity reflects the accumulated amounts of successfully spliced HaloTag-luciferase fusion products, whereas the amounts and sizes of HaloTag-containing proteins provide quantitative insights into precursor, correctly spliced, and aberrantly spliced mRNA species. Preliminary experiments confirmed that the dual reporter minigene assay can provide estimates of overall splicing efficiency based on the levels of protein products. We then used the minigene assay to analyze a case of chronic granulomatous disease that was caused by a G>C mutation at position +5 in the 5'-splice donor site of intron 5 of the CYBB gene. We found that the G>C mutation affected CYBB mRNA splicing by changing a delicate balance of splicing efficiencies of introns 4, 5, and 6.

HLA-class II and class I genotypes among Japanese children with Type 1A diabetes and their families

OBJECTIVE

To determine the HLA-DRB1, DQB1, DPB1, A, C, and B genotypes among Japanese children with autoimmune type 1 diabetes.

METHODS

Four hundred and thirty patients who were GADAb and/or IA-2Ab-positive (Type 1A) were recruited from 37 medical centers as part of a nationwide multicenter collaborative study. DNA samples from 83 siblings of the children with Type 1A diabetes and 149 parent-child trios were also analyzed. A case-control study and a transmission disequilibrium test (TDT) were then performed.

RESULTS

The susceptible and protective DRB1 and DQB1 alleles and haplotypes were confirmed. DPB1 alleles unique to the Japanese population and those common to multiple ethnic groups were also present. A linkage disequilibrium (LD) analysis showed both susceptible and protective haplotypes. The TDT did not reveal any alleles that were transmitted preferentially from the mother or father to children with Type 1A. Homozygosity for DRB1-09:01-DQB1-03:03 and heterozygosity for DRB1-04:05-DQB1-04:01 and DRB1-08:02-DQB1-03:02 were associated with an extremely high risk of Type 1A. A comparison of children with Type 1A and their parents and siblings suggested a dose effect of susceptible DRB1-DQB1 haplotypes and an effect of protective alleles on immunological pathogenesis. DRB1-09:01 appeared to be strongly associated with an early onset in preschool children with Type 1A diabetes.

CONCLUSIONS

This study demonstrated the characteristic association of HLA-class II and class I genes with Type 1A diabetes among Japanese children. A TDT did not reveal the genomic imprinting of HLA-class II and class I genes in Type 1A diabetes.

Nocturnal blood glucose and IGFBP-1 changes in type 1 diabetes: Differences in the dawn phenomenon between insulin regimens

OBJECTIVE

Insulin-like growth factor binding protein-1 (IGFBP-1) is known to regulate the bioavailability of insulin-like growth factor (IGF) and the levels of IGFBP-1 are increased in the morning in patients with type 1 diabetes mellitus. We investigated the nocturnal fluctuations of glucose, IGFBP-1, and free IGF-1 levels with three insulin regimens.

RESEARCH DESIGN AND METHODS

Forty-eight type 1 diabetes patients were divided into three groups according to their basal insulin therapy (continuous subcutaneous insulin infusion [CSII], insulin glargine, NPH insulin). Blood samples were obtained every 2 h between 2 300 h and 0700 h to measure plasma glucose, IGFBP-1 and free IGF-1 levels.

RESULTS

The dawn phenomenon was more frequent with NPH (62.1%) than with glargine (16.6%, p<0.05) and CSII (14.3%, p<0.05). In the NPH group, the serum IGFBP-1 levels were markedly increased from 21.0+/-3.6 ng/ml at 2 300 h to 200.3+/-21.8 ng/ml at 0700 h and free IGF-1 levels were inversely decreased; these changes were partially suppressed in the CSII and glargine groups.

CONCLUSIONS

The use of insulin regimens that provide sufficient insulin levels in the early morning can suppress the dawn phenomenon, leading to improved glycemic control. The increase in circulating IGFBP-1 in the morning, as a result of waning of insulin action, lowers free IGF-1 levels and may cause insulin resistance.

OTX2 loss of function mutation causes anophthalmia and combined pituitary hormone deficiency with a small anterior and ectopic posterior pituitary

CONTEXT

Orthodenticle homeobox 2 (OTX2) is a transcription factor necessary for ocular and forebrain development. In humans, heterozygous mutations of OTX2 cause severe ocular malformations. However, whether mutations of OTX2 cause pituitary structural abnormalities or combined pituitary hormone deficiency (CPHD) has not been clarified.

OBJECTIVES

We surveyed the functional consequences of a novel OTX2 mutation that was detected in a patient with anophthalmia and CPHD.

PATIENT

We examined a Japanese patient with growth disturbance, anophthalamia, and severe developmental delay. He showed deficiencies in GH, TSH, LH, FSH, and ACTH. Brain magnetic resonance imaging revealed a small anterior pituitary gland, invisible stalk, ectopic posterior lobe, and Chiari malformation.

RESULTS

Sequence analysis of OTX2 demonstrated a heterozygous two bases insertion [S136fsX178 (c.576-577insCT)] in exon 3. The mutant Otx2 protein localized to the nucleus, but did not activate the promoter of the HESX1 and POU1F1 gene, indicating a loss of function mutation. No dominant negative effect in the presence of wild-type Otx2 was observed.

CONCLUSION

This case indicates that the OTX2 mutation is a cause of CPHD. Further study of more patients with OTX2 defects is necessary to clarify the clinical phenotypes and endocrine defects caused by OTX2 mutations.

Analysis of weight at birth and at diagnosis of childhood-onset type 2 diabetes mellitus in Japan

BACKGROUND

The prevalence of childhood-onset type 2 diabetes mellitus (T2DM) has increased dramatically over the past two to three decades in Japan, but epidemiological and clinical data remain limited. Several epidemiological studies stress the importance of elucidating the pathophysiology of prenatal nutrition and other intra-uterine environmental factors and the risk of T2DM in each of the different populations. We examined the associations of weight at birth, weight at diagnosis of T2DM, and clinical characteristics of childhood-onset T2DM.

METHODS

Clinical data sheets were sent to councillors of the Japanese Society for Pediatric Endocrinology (JSPE) and members of the Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) in June 2003. Clinical data on 259 children (9-17 yr of age) categorized as T2DM by pediatric endocrinologists, who are members of the JSPE and/or JSGIT, using 1999 Japan Diabetes Society criteria were analyzed. Degree of overweight was assessed by percent overweight and standard deviation score-body mass index.

RESULTS

The age (mean +/- SD) of the 259 patients recruited (121 boys and 138 girls) was 11.9 +/- 2.1 yr at diagnosis and 14.4 +/- 2.0 yr at the time of the survey. Sixty-nine percent of all patients were obese (percent overweight >or=20%) at the time of diagnosis. Obese patients were older at the time of diagnosis and had a higher level of hemoglobin A1c (HbA1c) at diagnosis than non-obese patients (p < 0.05), and there were fewer girls than boys. Twenty two (11.3%) of 195 patients had low birth weights (<2500 g) and 19 (9.7%) had high birth weights (>or=4000 g). The frequencies of low and high birth weights were higher among patients with T2DM than among a control group, producing a U-shaped distribution (p < 0.05). The frequency of a family history of diabetes was lower among low-birth weight patients. In contrast, high-birth weight patients had a higher prevalence of diabetic mothers and medication including insulin therapy (p < 0.05).

CONCLUSIONS

Obesity was shown to be a major risk factor for childhood-onset T2DM in Japan. The frequencies of low and high birth weights were higher among patients with T2DM, and differences in clinical characteristics, such as family history of diabetes, were recognized among patients with T2DM with low, normal, and high birth weights.

Short-term plasticity of central benzodiazepine receptors in status epilepticus: case report

(123)I-iomazenil SPECT is of value in determining an epileptogenic focus, however, transient uptake change has been rarely reported in epileptic disorders. A 78-year-old woman diagnosed as status epilepticus (SE) showed transient reduction in (123)I-iomazenil uptake within the epileptic foci on SPECT images during a couple of weeks. It suggests a seizure-related 'short-term' plasticity in the central benzodiazepine receptors and dynamic change in the regulatory mechanisms of inhibitory neurotransmitter system within the epileptic foci in patients with SE.

Metabolic syndrome in youths

The metabolic syndrome (MetS), characterized by a clustering of cardiovascular disease and type 2 diabetes (T2DM) risk factors, has become prevalent in children and adolescents in recent years. However, the reported prevalence data on the MetS in youths has varied markedly, in large part, because of the disagreement among the variously proposed definitions of the MetS. Obesity is defined by using body mass index, waist circumference, or percent overweight, pointing to the need for standardized use of anthropometric variables to define obesity with a well-defined reference year for each ethnic population. In addition, slightly different cutoff values are used for triglycerides, high-density lipoprotein cholesterol, blood pressure, and fasting plasma glucose. Therefore, International Diabetes Federation recently proposed unified, easy-to-use criteria for diagnosing the MetS in youths. To provide insight into the mechanisms underlying the MetS in youths, the degree of insulin sensitivity/resistance and its correlation with the serum lipid and blood pressure levels have been evaluated. In addition, the serum levels of adipocytokines, such as adiponectin, leptin, tumor necrosis factor-alpha, resistin, interleukin-6, plasminogen activator inhibitor-1, and their correlation with childhood obesity have been extensively investigated. Recommendations for future research include exploring ways to assess visceral adiposity, to identify better biochemical markers for prediction of T2DM and disease progression, and to effectively intervene to prevent the MetS in youths.

Relatively small birth size and accelerated early growth of Japanese type 1 diabetic children with younger onset

We investigated the changes of anthropometrical parameters in Japanese children with type 1 diabetes (T1DM) from birth to the onset of diabetes. One-hundred ninety-nine children (79 males and 120 females) diagnosed between 0-16 yr of age during the period between 1990 and 2003 were the subjects of this study. The subjects were categorized into 3 groups according to onset age (0-5 yr; n=74, 5-10 yr; n=61, 10-16 yr; n=64). At birth, the younger onset (<5) group had significant lower height and weight standard deviation score (SDS) compared with the older onset (5≤) group (p=0.01 and p=0.02, respectively). When the changes in height SDS from birth to onset were compared, height SDS at onset were significantly greater than those at birth in the younger onset group (p<0.001). However, no significant difference was observed in the other groups (p=0.95 and p=0.39). These results suggest that relatively small size at birth and accelerated growth after birth until the onset of diabetes may be a characteristic of Japanese T1DM children with younger onset and may further support the hypothesis that emphasizes accelerated growth and subsequent insulin resistance as a cause of earlier onset of T1DM.

The association of CTLA4 polymorphism with type 1 diabetes is concentrated in patients complicated with autoimmune thyroid disease: a multicenter collaborative study in Japan

CONTEXT

Transracial studies are a powerful tool for genetic association studies of multifactorial diseases, such as type 1 diabetes. The low incidence of type 1 diabetes in Asian countries, however, makes it difficult to perform large-scale studies in Asia.

OBJECTIVE

To overcome this, we have assembled a multicenter study group in Japan and studied the association of CTLA4 polymorphisms with type 1 diabetes relative to autoimmune thyroid disease (AITD) phenotypes.

SUBJECTS

Subjects included a total of 1837 samples, including 1114 cases (769 with type 1 diabetes and 345 with AITD) and 723 control subjects.

METHODS

The +6230G>A and +49G>A polymorphisms of CTLA4 as well as HLA-DRB1 and -DQB1 were genotyped.

RESULTS

The +6230G>A polymorphism was significantly associated with type 1 diabetes complicated with AITD (odds ratio, 1.54; P = 0.027) and with AITD alone (odds ratio, 1.31; P = 0.045) but not with type 1 diabetes without AITD. The association with type 1 diabetes positive for autoantibodies to both pancreatic islets and thyroid was particularly strong (odds ratio, 1.87; P = 0.001). Type 1 diabetic patients with the disease-associated GG genotype were characterized by a significantly higher frequency of AITD (P = 0.013), of positivity for both AITD and antiislet autoantibody (P = 0.00086), and of high-risk HLA genotypes (P = 0.034).

CONCLUSIONS

Given the high frequency of AITD in patients with type 1 diabetes, these data suggest the possibility that the association of CTLA4 with type 1 diabetes in previous studies may have been secondary to AITD, suggesting the importance of subclassification of type 1 diabetes relative to AITD in genetic studies.

Survey of current medical treatments for childhood-onset type 2 diabetes mellitus in Japan

The prevalence of childhood-onset type 2 diabetes mellitus has increased dramatically over the past two or three decades in Japan, but epidemiological and clinical data remain limited. This survey was conducted to elucidate the current use of antidiabetic medications and the efficacy, safety and problems associated with the use of these agents. Clinical data on 259 children (younger than 18 yr of age; 121 boys and 138 girls) with type 2 diabetes treated at 42 medical centers throughout Japan between June and September 2003 were analyzed. Sixty-nine percent of all the type 2 diabetic patients (78% of the boys, 63% of the girls) were obese (percent overweight ≥ 20%) at the time of diagnosis. Overall, 172 subjects (66%) were treated using anti-hyperglycemic agents, including α-glucosidase inhibitors (α-GI), insulin, metformin and sulfonylureas (SUs). Many patients who were initially treated with a single medication eventually required insulin alone or in combination with an additional agent, suggesting that their diabetic control had deteriorated during the course of treatment. The HbA1c level of the 14 subjects who received only metformin decreased significantly without an improvement in obesity. Three cases with adverse events were reported, but causal relations with anti-hyperglycemic agents were not clear. In conclusion, mainly α-GI, insulin and metformin have been prescribed for childhood-onset type 2 diabetes patients in Japan. The results of this survey suggest that metformin is safe and effective for the treatment of type 2 diabetes with obesity in children and adolescents.

Malignant transformation of endometriosis and genetic alterations of K-ras and microsatellite instability

OBJECTIVES

To clarify the role of specific genetic alterations in the multi-step process of malignant transformation of endometriosis.

METHODS

In cases of ovarian endometrioid carcinoma, we separated regions of normal endometriosis, atypical endometriosis and ovarian endometrioid carcinoma by laser microdissection, and examined K-ras mutation and microsatellite instability in each separated tissue sample.

RESULTS

We detected K-ras mutation and microsatellite instability in endometrioid carcinoma tissue, but not in normal or atypical endometriosis bordering the cancerous region.

CONCLUSIONS

The present findings suggest that K-ras mutation and microsatellite instability are associated with malignant transformation from atypical endometriosis to ovarian endometrioid carcinoma.

Past 10-year status of insulin therapy for preschool-age Japanese children with type 1 diabetes

The aim of this study was to evaluate the past 10-year status of insulin therapy for preschool-age children with type 1 diabetes in Japan. One-hundred and forty-two patients who had been diagnosed at less than 5 years of age within the past 10 years (1993-2002) at 36 hospitals were registered in this study on April 2003. The methods of daily insulin therapy and episodes of severe hypoglycemia during the preschool period were investigated. Eighty-six (60.6%) children were treated with a pen-type device and 56 (39.4%) were treated with a syringe-type device. The once-a-day insulin regimen was used for 2, a twice-a-day regimen for 104, a three-times-a-day for 28 and a four-times-a-day for 8. Episodes of severe hypoglycemia were recorded in nearly half of the subjects, and one-fourth of the subjects had repeated episodes. One hundred and eleven of their parents were questioned regarding the degree of psychosocial stress experienced during the care of their children. Most parents worried about the glycosylated hemoglobin value at each hospital visit. They were next very afraid of nocturnal severe hypoglycemia, independent of any actual experience. These results suggest that although insulin therapy can involve various methods, the important point is to simultaneously provide good glycemic control and prevent severe hypoglycemia, especially during this age.

Detection of p53 mutations in the plasma DNA of patients with ovarian cancer

Mutation of p53 is one of the most common genetic abnormalities detected in up to 81% of cases of ovarian cancer. To evaluate the use of plasma DNA analysis as a method for somatic mutation screening, we measured the presence of p53 mutations in DNA isolated from plasma and cancer tissue from patients with ovarian cancer. We analyzed the plasma DNA for the presence of p53 mutations (exons 5-8). Of 27 cases of ovarian cancer, 12 cases (44%) had mutations of p53 in cancer tissue. In two of the 12 cases (16.7%), identical mutations were detected in DNA of their preoperative plasma. In our follow-up of the two patients with p53 mutations in their plasma, mutant DNA was undetectable in their plasma after surgery. In one case, the p53 mutation re-surfaced in their plasma 16 months after surgery, and the patient died 2 months later. We have shown that tumor-derived DNA can be detected in the plasma of some patients with ovarian cancer, particularly in those with more advanced stage.