Keisuke Nagasaki

Usefulness of Serum Adiponectin Level as a Diagnostic Marker of Metabolic Syndrome in Obese Japanese Children

This study aimed 1) to investigate the relationship between serum adiponectin levels and metabolic disorders and 2) to clarify the usefulness of serum adiponectin level as a diagnostic marker of metabolic syndrome in obese Japanese children. One hundred obese boys aged 8 to 13 years were examined. Serum adiponectin levels were measured by radioimmunoassay using a commercial kit. Abdominal fat thickness (maximum preperitoneal fat thickness: Pmax; minimum subcutaneous fat thickness: Smin) was measured by ultrasonography. The relationships between adiponectin and clinical characteristics were analyzed by simple regression. The relationships between anthropometric measurements and metabolic disorders were analyzed among three groups divided according to adiponectin percentile. The prevalence of metabolic syndrome was also analyzed, with metabolic syndrome defined as the presence of three or more complications of obesity. The criteria for metabolic syndrome by adiponectin were subjected to a receiver operating characteristic (ROC) analysis. Body weight, waist circumference, Pmax, alanine aminotransferase and fasting serum insulin were all inversely correlated with adiponectin. There were significant differences in the prevalence of severe obesity, the accumulation of visceral adipose tissue, hyperinsulinemia, high serum low density lipoprotein-cholesterol, the number of complications of obesity and the prevalence of metabolic syndrome among the three groups. The area under the ROC curve for adiponectin was 0.672±0.055 and the cut-off value was 6.65 μg/ml. Hypoadiponectinemia was associated with visceral fat accumulation and metabolic syndrome in obese Japanese boys. Evaluation of adiponectin might contribute to an early intervention for obese children with metabolic syndrome.

Obese Japanese children have low bone mineral density after puberty

The purpose of this study was to determine the relationship between BMD and childhood obesity. We examined 1070 obese children (722 boys and 348 girls) aged 7 to 15 years. Their mean relative weight, as a percentage of the standard weight for age, height, and sex, was 152.9 ± 14%. BMD was assessed, by a digital image processing method, in the second metacarpal bone of the left hand. We compared our results with those of healthy nonobese Japanese children based on both chronological and bone age. Mean BMD values for bone age in the obese children were significantly higher than those in control groups in boys aged 11 years and under and girls 9 years and under. On the other hand, in boys over 12 years old, BMD values for bone age were lower than those in the control groups. In girls over 11 years old, BMD values tended to be lower than those in the control groups. In conclusion, we studied the BMD of obese children from the point of view of advanced bone age. Our results showed that BMD was higher than in prepubertal obese children, but a low BMD value was found after puberty, due to poor gain of BMD during puberty. It is important to prevent obesity in childhood in order to prevent the low BMD after puberty.

PRKAR1A Mutation Affecting cAMP-Mediated G Protein-Coupled Receptor Signaling in a Patient with Acrodysostosis and Hormone Resistance

CONTEXT Acrodysostosis is a rare autosomal dominant disorder characterized by short stature, peculiar facial appearance with nasal hypoplasia, and short metacarpotarsals and phalanges with cone-shaped epiphyses. Recently, mutations of PRKAR1A and PDE4D downstream of GNAS on the cAMP-mediated G protein-coupled receptor (GPCR) signaling cascade have been identified in acrodysostosis with and without hormone resistance, although functional studies have been performed only for p.R368X of PRKAR1A. OBJECTIVE Our objective was to report a novel PRKAR1A mutation and its functional consequence in a Japanese female patient with acrodysostosis and hormone resistance. PATIENT This patient had acrodysostosis-compatible clinical features such as short stature and brachydactyly and mildly elevated serum PTH and TSH values. RESULTS Although no abnormality was detected in GNAS and PDE4D, a novel de novo heterozygous missense mutation (p.T239A) was identified at the cAMP-binding domain A of PRKAR1A. Western blot analysis using primary antibodies for the phosphorylated cAMP-responsive element (CRE)-binding protein showed markedly reduced CRE-binding protein phosphorylation in the forskolin-stimulated lymphoblastoid cell lines of this patient. CRE-luciferase reporter assays indicated significantly impaired response of protein kinase A to cAMP in the HEK293 cells expressing the mutant p.T239A protein. CONCLUSIONS The results indicate that acrodysostosis with hormone resistance is caused by a heterozygous mutation at the cAMP-binding domain A of PRKAR1A because of impaired cAMP-mediated GPCR signaling. Because GNAS, PRKAR1A, and PDE4D are involved in the GPCR signal transduction cascade and have some different characters, this would explain the phenotypic similarity and difference in patients with GNAS, PRKAR1A, and PDE4D mutations.

Lower Birth Weight and Visceral Fat Accumulation Are Related to Hyperinsulinemia and Insulin Resistance in Obese Japanese Children

This study aimed to reveal the relation of birth weight (or the birth weight standard deviation score [BWSDS]) and visceral fat accumulation to hyperinsulinemia and insulin resistance. We examined obese Japanese children (650 boys and 317 girls) with a mean age of 10.3 years (range, 6–15 years). The mean percentage of overweight to the standard body weight of Japanese children was 52.1% in boys and 51.4% in girls. Abdominal fat thickness (maximum preperitoneal fat thickness; Pmax) was measured using ultrasonography. The fasting serum insulin and plasma glucose levels were measured, and the homeostasis model assessment-insulin resistance (HOMA-R) and quantitative insulin sensitivity check index (QUICKI) were calculated. We divided the subjects into four groups according to their birth weight or BWSDS, and compared anthropometric measurements, Pmax, blood pressure, serum insulin levels, HOMA-R and QUICKI among the quartiles. The relationships of both birth weight (or BWSDS) and Pmax to serum insulin levels (or HOMA-R, QUICKI) were examined with multiple regression analyses. The fasting serum insulin level and HOMA-R were highest in the quartile with the lowest birth weight or BWSDS. The birth weight and BWSDS were inversely related to the serum insulin levels and HOMA-R, positively related to QUICKI, and independent of Pmax. Our findings suggest that both lower birth weight and visceral fat accumulation may be independently related to hyperinsulinemia and insulin resistance in obese Japanese children.

West syndrome associated with mosaic duplication of FOXG1 in a patient with maternal uniparental disomy of chromosome 14

FOXG1 on chromosome 14 has recently been suggested as a dosage‐sensitive gene. Duplication of this gene could cause severe epilepsy and developmental delay, including infantile spasms. Here, we report on a female patient diagnosed with maternal uniparental disomy of chromosome 14 and West syndrome who carried a small supernumerary marker chromosome. A chromosomal analysis revealed mosaicism of 47,XX, + mar[8]/46,XX[18]. Spectral karyotyping multicolor fluorescence in situ hybridization analysis confirmed that the marker chromosome was derived from chromosome 14. A DNA methylation test at MEG3 in 14q32.2 and microsatellite analysis using polymorphic markers on chromosome 14 confirmed that the patient had maternal uniparental disomy 14 as well as a mosaic small marker chromosome of paternal origin containing the proximal long arm of chromosome 14. Microarray‐based comparative genomic hybridization analysis conclusively defined the region of the gain of genomic copy numbers at 14q11.2‐q12, encompassing FOXG1. The results of the analyses of our patient provide further evidence that not only duplication but also a small increase in the dosage of FOXG1 could cause infantile spasms.

Nonclassic TSH resistance: TSHR mutation carriers with discrepantly high thyroidal iodine uptake

CONTEXT Inactivating mutations in the TSH receptor gene (TSHR) cause TSH resistance. Most patients with TSH resistance have low to normal thyroidal radioiodine uptake (RAIU), which is consistent with the physiological knowledge that TSH stimulates iodine uptake. To date, only one TSHR mutation-carrying family with discrepantly high RAIU has been reported. OBJECTIVE We aimed to test whether TSHR mutation carriers with high RAIU are observed in a cohort of Japanese patients with congenital hypothyroidism (CH). SUBJECTS AND METHODS Twenty-four Japanese CH patients with high RAIU were screened for TSHR mutations. The capacities of mutant TSHR to activate Gs- and Gq-coupled signaling pathways were evaluated in vitro. RESULTS Two patients were found to have biallelic TSHR mutations: p.[T145I]+[R450H] in one and p.[R450H]+[I661fs] in the other. The two subjects had permanent CH with slightly high RAIU (41.8 and 43.0%, reference 8-40) but did not have goiter. One had a slightly high perchlorate discharge rate (10%, reference <10). Expression experiments revealed that T145I-TSHR retained partial ability to transduce both Gs- and Gq-coupled pathways, whereas I661fs-TSHR could transduce neither of them. R450H-TSHR had partial ability to transduce Gs-coupled signaling but had abrogated ability to transduce Gq-coupled signaling, indicating that coupling to Gq was dominantly affected. CONCLUSIONS We show that 8% of Japanese CH patients with high RAIU (two in 24) has inactivating TSHR mutations. Expression of this apparently discrepant phenotype, which we term nonclassic TSH resistance, is presumably associated with the characteristic signaling property of the mutant TSHR, namely the Gq-dominant coupling defect.

Lower Birth Weight Associated with Current Overweight Status Is Related with the Metabolic Syndrome in Obese Japanese Children

The purpose of this study was to clarify the relationship between lower birth weight and current overweight status and to examine the involvement of these factors in the development of the metabolic syndrome (MS) in obese Japanese children. We examined 97 obese boys (mean age 11.3 years; mean percentage overweight [POW] 52.4%) and 29 obese girls (mean age 11.1 years; mean POW 58.3%). The anthropometric measurements, blood pressure, fasting serum insulin and blood glucose, liver enzymes, lipids and lipoproteins were measured. Birth weight and gestational weeks were also recorded. The subjects were divided into either an MS group or a Non-MS group using criteria proposed for Japanese children. We compared the weight parameters (birth weight, current weight and current weight–to−birth weight ratio [WBWR]) between the two groups and analyzed the relationships between the weight parameters and metabolic derangements. There were no significant differences in age or anthropometric measurements between the two groups. However, birth weight in the MS group was lower than that in the Non-MS group, while WBWR of the MS group was higher than that in the Non-MS group. Blood pressure and serum insulin correlated positively with WBWR. These findings suggested that lower birth weight with current overweight status was associated with the MS in obese Japanese children. We were unable to clarify whether subjects with lower birth weight who achieved proper weight gains had the same risk as subjects with appropriate birth weight. However, they should be assisted to grow adequately to prevent future metabolic derangements.

Rare pseudoautosomal copy-number variations involving SHOX and/or its flanking regions in individuals with and without short stature

Pseudoautosomal region 1 (PAR1) contains SHOX, in addition to seven highly conserved non-coding DNA elements (CNEs) with cis-regulatory activity. Microdeletions involving SHOX exons 1–6a and/or the CNEs result in idiopathic short stature (ISS) and Leri–Weill dyschondrosteosis (LWD). Here, we report six rare copy-number variations (CNVs) in PAR1 identified through copy-number analyzes of 245 ISS/LWD patients and 15 unaffected individuals. The six CNVs consisted of three microduplications encompassing SHOX and some of the CNEs, two microduplications in the SHOX 3′-region affecting one or four of the downstream CNEs, and a microdeletion involving SHOX exon 6b and its neighboring CNE. The amplified DNA fragments of two SHOX-containing duplications were detected at chromosomal regions adjacent to the original positions. The breakpoints of a SHOX-containing duplication resided within Alu repeats. A microduplication encompassing four downstream CNEs was identified in an unaffected father–daughter pair, whereas the other five CNVs were detected in ISS patients. These results suggest that microduplications involving SHOX cause ISS by disrupting the cis-regulatory machinery of this gene and that at least some of microduplications in PAR1 arise from Alu-mediated non-allelic homologous recombination. The pathogenicity of other rare PAR1-linked CNVs, such as CNE-containing microduplications and exon 6b-flanking microdeletions, merits further investigation.

A family of pseudohypoparathyroidism type Ia with an 850-kb submicroscopic deletion encompassing the whole GNAS locus†

A Family of Pseudohypoparathyroidism Type Ia With an 850-kb Submicroscopic Deletion Encompassing the Whole GNAS Locus Toshikatsu Mitsui, Keisuke Nagasaki, Masaki Takagi, Satoshi Narumi, Tomohiro Ishii, and Tomonobu Hasegawa* Department of Pediatrics, Keio University School of Medicine, Tokyo Japan Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medicine and Dental Sciences, Niigata, Japan

Molecular basis of non-syndromic hypospadias: systematic mutation screening and genome-wide copy-number analysis of 62 patients

STUDY QUESTION What percentage of cases with non-syndromic hypospadias can be ascribed to mutations in known causative/candidate/susceptibility genes or submicroscopic copy-number variations (CNVs) in the genome? SUMMARY ANSWER Monogenic and digenic mutations in known causative genes and cryptic CNVs account for >10% of cases with non-syndromic hypospadias. While known susceptibility polymorphisms appear to play a minor role in the development of this condition, further studies are required to validate this observation. WHAT IS KNOWN ALREADY Fifteen causative, three candidate, and 14 susceptible genes, and a few submicroscopic CNVs have been implicated in non-syndromic hypospadias. STUDY DESIGN, SIZE, DURATION Systematic mutation screening and genome-wide copy-number analysis of 62 patients. PARTICIPANTS/MATERIALS, SETTING, METHODS The study group consisted of 57 Japanese and five Vietnamese patients with non-syndromic hypospadias. Systematic mutation screening was performed for 25 known causative/candidate/susceptibility genes using a next-generation sequencer. Functional consequences of nucleotide alterations were assessed by in silico assays. The frequencies of polymorphisms in the patient group were compared with those in the male general population. CNVs were analyzed by array-based comparative genomic hybridization and characterized by fluorescence in situ hybridization. MAIN RESULTS AND THE ROLE OF CHANCE Seven of 62 patients with anterior or posterior hypospadias carried putative pathogenic mutations, such as hemizygous mutations in AR, a heterozygous mutation in BNC2, and homozygous mutations in SRD5A2 and HSD3B2. Two of the seven patients had mutations in multiple genes. We did not find any rare polymorphisms that were abundant specifically in the patient group. One patient carried mosaic dicentric Y chromosome. LIMITATIONS, REASONS FOR CAUTION The patient group consisted solely of Japanese and Vietnamese individuals and clinical and hormonal information of the patients remained rather fragmentary. In addition, mutation analysis focused on protein-altering substitutions. WIDER IMPLICATIONS OF THE FINDINGS Our data provide evidence that pathogenic mutations can underlie both mild and severe hypospadias and that HSD3B2 mutations cause non-syndromic hypospadias as a sole clinical manifestation. Most importantly, this is the first report documenting possible oligogenicity of non-syndromic hypospadias. STUDY FUNDING/COMPETING INTERESTS This study was funded by the Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology; by the Grant-in-Aid from the Japan Society for the Promotion of Science; by the Grants from the Ministry of Health, Labour and Welfare, from the National Center for Child Health and Development and from the Takeda Foundation. The authors have no competing interests to disclose. TRIAL REGISTRATION NUMBER Not applicable.