Genotype-Phenotype Correlations in Thirty Japanese Patients with Congenital Hypothyroidism Attributable to TG Defects.

CONTEXT: Thyroglobulin (Tg), encoded by TG, is essential for thyroid hormone synthesis. TG defects result in congenital hypothyroidism (CH). Most reported patients were born before the introduction of newborn screening (NBS). OBJECTIVE: We aimed to clarify the phenotypic features of patients with TG defects diagnosed and treated since the neonatal period. SUBJECTS AND METHODS: We screened 1061 patients with CH for thirteen CH-related genes and identified thirty patients with TG defects. One patient was diagnosed due to hypothyroidism-related symptoms and the rest were diagnosed via NBS. Patients were divided into two groups according to their genotypes, and clinical characteristics were compared. We evaluated the functionality of the seven missense variants using HEK293 cells. RESULTS: Twenty-seven rare TG variants were detected, including fifteen nonsense, three frameshift, two splice-site, and seven missense variants. Patients were divided into two groups: thirteen patients with biallelic truncating variants and seventeen patients with monoallelic/biallelic missense variants. Patients with missense variants were more likely to develop thyroid enlargement with TSH stimulation than patients with biallelic truncating variants. Patients with biallelic truncating variants invariably required full hormone replacement, whereas patients with missense variants required variable doses of levothyroxine. Loss of function of the seven missense variants was confirmed in vitro. CONCLUSION: To our knowledge, this is the largest investigation on the clinical presentation of TG defects diagnosed in the neonatal period. Patients with missense variants showed relatively mild hypothyroidism with compensative goiter. Patients with only truncating variants showed minimal or no compensative goiter and required full hormone replacement.

A Pediatric Case of Graves' Hyperthyroidism with Associated Glucose Intolerance Detected by a Urine Glucose Screening Program at School.

We report here a 13-year-old female with Graves' disease, whose diagnostic clue was glycosuria, which was detected by a urine glucose screening program at school. She had had mild general malaise, and a physical examination revealed a slightly enlarged thyroid gland. Hyperthyroidism (thyroid-stimulating hormone (TSH) < 0.01 µU/ml, free triiodothyronine (fT3) 23.57 pg/ml, free thyroxine (fT4) 3.38 ng/dl) and anti-thyroid autoantibodies (TRAb 43.6%) were detected in laboratory tests, and her plasma glucose at 120 minutes was 142 mg/dl in a 75 g oral glucose tolerance test. She was diagnosed as having borderline diabetes. These findings revealed a diagnosis of Graves' hyperthyroidism with associated impaired glucose tolerance. Although it is reported that many adults with hyperthyroidism develop disorders of glucose metabolism, pediatric patients rarely have complications of glucose intolerance or diabetes mellitus, and there are no previous reports of Graves' disease diagnosed by a urine glucose screening program at school. This case suggests a possibility of abnormalities in glucose metabolism even in pediatric cases of Graves' disease. To avoid overlooking the diagnosis of glucose intolerance associated with hyperthyroidism, a careful medical interview and examination should be performed even if the clinical features are mild.

[Evaluation of Clinical Features and Growth Hormone Deficiency in Short Children Born Small For Gestational Age].

Growth hormone (GH) therapy for short children born small for gestational age (SGA) has been approved in Japan. It is important to evaluate GH secretion ability before the initiation of GH therapy because there are some differences in dose and medical expenses between short children born SGA and GH deficiency (GHD). This study was designed to elucidate the incidence of GHD and to find a useful marker for detecting it in short SGA children. We retrospectively reviewed medical records to analyze the clinical features of short children born SGA and with GHD who had started GH therapy before the age of 6 in the University Hospital of Occupational and Environmental Health and Kyushu Rousai Hospital. Nine of 22 SGA subjects (41%) had GHD. There were no significant differences between two groups of short SGA children (GHD, non-GHD) in the median of height and serum insulin-like growth factors (IGF)-1 levels at birth or at the start of GH therapy. The probability of GHD was higher if the height standard deviation scores (SD) of the SGA children were lower than -3.2 (odds ratio, 11.6; 95% confidence interval, 1.52 - 89.1, P = 0.013). This study showed that there is an approximately 40% incidence of GHD in short SGA children needing GH treatment. We should do GH stimulation tests for short SGA children whose height SD is lower than -3 to determine the appropriate GH therapy.

Plasma but not serum brain-derived neurotrophic factor concentration is decreased by oral glucose tolerance test-induced hyperglycemia in children.

BACKGROUND: Little is known regarding the relationships among circulating brain-derived neurotrophic factor (BDNF) levels and glucose or insulin in children and adolescents. The objective of this study was to investigate whether circulating BDNF levels would change during the oral glucose tolerance test (OGTT). METHODS: We performed the OGTT and measured the serial changes in BDNF levels in both plasma and serum. RESULTS: There were 22 subjects in the normal type (N) group and 20 in the borderline/diabetic type (B/D) group, defined by the results of the OGTT. Serum levels of BDNF were almost five times higher and plasma levels gradually decreased during the OGTT, whereas serum levels showed no significant change. The reduction of plasma BDNF level changes from baseline to 120 min were significantly different between the N and B/D groups (36.3% vs. 20.8%, p=0.023). CONCLUSIONS: Our results showed that plasma levels of BDNF are more sensitive to acute changes in glucose or insulin levels than serum.

Sporadic pseudohypoparathyroidism type-1b with asymptomatic hypocalcemia.

Pseudohypoparathyroidism type 1b (PHP-1b) is usually diagnosed on various symptoms of hypocalcemia. Previous studies reported a few cases of autosomal dominant pattern PHP-1b identified on familial analysis with asymptomatic hypocalcemia. Herein we report the case of a 6-year-old male patient with sporadic PHP-1b incidentally detected on preoperative examination. He had neither characteristic findings of Albright hereditary osteodystrophy nor evidence of tetany. Sporadic PHP-1b was diagnosed on the basis of clinical observation and laboratory examination. In addition, genetic testing using methylation-specific multiplex ligation-dependent probe amplification indicated broad methylation abnormalities and confirmed the sporadic form of PHP-1b. Sporadic PHP-1b might often be overlooked when diagnosis is done simply on definitive clinical features. To avoid this, DNA sequencing and methylation analysis should be performed even in the absence of definitive clinical features.

Tamoxifen treatment for pubertal gynecomastia in two siblings with partial androgen insensitivity syndrome.

BACKGROUND: Although tamoxifen has been shown to be fairly safe and effective for idiopathic pubertal gynecomastia, it remains unknown whether it is also beneficial for gynecomastia associated with endocrine disorders. Here, we report the effect of tamoxifen on pubertal gynecomastia in 2 siblings with partial androgen insensitivity syndrome (PAIS). CASE REPORTS: Cases 1 and 2 presented with persistent pubertal gynecomastia at 13 and 16 years of age, respectively. Physical examinations revealed breast of Tanner stage 3 and normal male-type external genitalia in both cases. Clinical features such as female-type pubic hair and borderline small testis indicated mildly impaired masculinization. RESULTS: Molecular analysis identified a previously reported p.Arg789Ser mutation in the androgen receptor gene (AR) in the 2 cases. Two months of oral administration of tamoxifen ameliorated gynecomastia to Tanner stage 2 with no adverse events. Additional treatment with testosterone enanthate showed negligible effects on body hair and penile length. Hormone values of the 2 cases during tamoxifen treatment remained similar to those in previously reported untreated patients with PAIS. CONCLUSION: The results indicate that tamoxifen was effective in treating pubertal gynecomastia in these 2 patients with PAIS and may be considered as a therapeutic option in this situation pending further studies.

An Infantile Case of Transient, Severe Hypercholesterolemia with Normalization after Complete Weaning from Breast-feeding.

A 20-d-old boy was referred to our department because of hyperthyrotropinemia at neonatal mass screening and diagnosed with neonatal transient hyperthyrotropinemia. A follow-up examination when the patient was 5 mo old revealed severe hypercholesterolemia. Familial hypercholesterolemia was first suspected because of the patient's significantly high levels of total and low-density lipoprotein cholesterol. The parent's serum lipid profiles were examined and found to be normal. He was completely breast-fed until 6 mo of age. Breast milk was still the main source of food for a period following weaning. At 14 mo old, the patient was weaned completely from breast milk, and his serum cholesterol levels decreased dramatically. According to the normal lipid profiles of the patient's parents and the spontaneous normalization of serum cholesterol levels after complete weaning from breast milk, breast-feeding was suggested to be responsible for his transient severe hypercholesterolemia. It is well documented that breast-fed infants have higher serum cholesterol levels than formula-fed infants. However, there is no reported case with severe hypercholesterolemia equivalent to or higher than the levels observed in the case of familial hypercholesterolemia. Although the exact mechanism is unknown, it is necessary to consider that a small number of cases develop severe hypercholesterolemia related to breast-feeding.

[Prevalence of 'obesity disease' and 'metabolic syndrome' in obese pediatric outpatients at the University Hospital of Occupational and Environmental Health, Japan].

'Obesity Disease for Japanese Children' was defined in 2002, and very recently 'Metabolic Syndrome (MS) for Japanese Children' was also defined. We therefore aimed to determine the prevalence of these two among the obese pediatric outpatients at our university hospital. The subjects were 97 children, 58 boys and 39 girls, ranging in age from 5 to 15 years. A child was considered to be obese when the body weight exceeded 120% of the standard body weight. All the subjects exceeded 120% overweight, and 58 children (35 boys and 23 girls) were over 150% overweight. Eighty five children (53 boys and 32 girls) were diagnosed with obesity disease (87.6%). Sixteen children (12 boys and 4 girls) were diagnosed with metabolic syndrome, which was 16.5% of all the subjects and 18.8% of the children with obesity disease. Fourteen of the 16 children with MS were over 10 years old. Obesity disease is diagnosed when the child has an obesity disease score of more than 6. The obesity disease score was significantly correlated with the waist circumference and the visceral adipose tissue area measured by computed tomography. The mean score of the children with MS was significantly higher than that of the non-MS group (30.2 vs. 12.3 points). In this study, it was clear that about 90% of our clinic patients are in the obesity disease group, and need therapeutic interventions. The prevalence of MS in the pediatric age is very low compared with that of adults, but MS is a high-risk category of obesity disease.

Plasma visfatin concentration as a surrogate marker for visceral fat accumulation in obese children.

OBJECTIVE: This study was designed to elucidate whether the plasma visfatin level reflects visceral or subcutaneous fat accumulation and metabolic derangement in obese children. METHODS AND PROCEDURES: Fifty-six obese Japanese children, including 37 boys and 19 girls were enrolled in the study. The age of the subjects ranged from 5 to 15 (10.2 +/- 0.3; mean +/- s.e.m.) years. The age-matched control group for measuring visfatin consisted of 20 non-obese children. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas were measured by computed tomography. The plasma concentrations for visfatin and leptin were assayed by enzyme-linked immunosorbent assay kits. RESULTS: The plasma visfatin level was higher in the obese (14.7 +/- 0.9 ng/ml) than in the control children (8.6 +/- 0.6 ng/ml). In a univariate analysis, the visfatin correlated significantly with age, height, body weight, waist circumference, VAT and SAT area, triglyceride (TG), insulin, and the homeostasis model assessment for insulin resistance (HOMA-R). After being adjusted for age and sex, only the VAT area retained significant partial correlation with visfatin, and in contrast the body weight, BMI-s.d., and SAT area with leptin. The plasma visfatin concentration was not correlated with leptin. The plasma visfatin levels in the control, non-metabolic syndrome (MS) (n = 49), and MS groups (n = 7) were significantly different from each other. DISCUSSION: These results suggest that plasma visfatin level is a specific marker for visceral fat accumulation in obese children. As a good surrogate marker, plasma visfatin level can predict the VAT area in obese children.

Inhibition of peroxisomal functions due to oxidative imbalance induced by mistargeting of catalase to cytoplasm is restored by vitamin E treatment in skin fibroblasts from Zellweger syndrome-like patients.

Many of the peroxisomal diseases exhibit excessive oxidative stress leading to neurological alterations and dysfunction. The role of peroxisomal oxidative stress in cellular function was highlighted by the loss of metabolic functions in peroxisomes of mutant cell lines, where catalase is mistargeted to the cytoplasm, but restored to peroxisomes by genetic manipulation (Sheikh et al. [Proc. Natl. Acad. Sci. USA 95 (1998) 2961)]. We report here that two human skin fibroblast cell lines from Zellweger syndrome-like patients are defective in the import of catalase into peroxisomes, causing impairment of metabolic function of this organelle. However, by lowering the cell culturing temperature (30 degrees C) the targeting of catalase to peroxisomes was restored, and with it the metabolic functions. Furthermore, mislocalization of catalase induces an oxidative imbalance in the cells which on treatment with a natural antioxidant, alpha-tocopherol (vitamin E), resulted in reduction of the oxidative levels and restoration of metabolic function (peroxisomal beta-oxidation and levels of very long chain fatty acids and plasmalogen as well as alpha-oxidation of branched-chain fatty acids). However, restoration of peroxisomal functions was not associated with the targeting of catalase to peroxisomes. Therefore, our finding suggests that correction of mistargeted catalase to peroxisomes is a temperature sensitive event and supports the hypotheses that its location outside peroxisomes induces an oxidative imbalance that results in metabolic dysfunction. The imbalance can be reversed by treatment with vitamin E, leading to normalization of peroxisomal functions. These findings open a novel approach for therapeutic treatment of certain peroxisomal disorders where gene or hypothermic therapies are not an option.

Plasma levels of orexin-a and leptin in obese children.

The present study was designed to determine the plasma level of orexin and its relationship with other metabolic and anthropometric markers in obese children. Forty-seven obese Japanese children, consisting of 31 boys and 16 girls, were enrolled in the study. Their ages were 10.4 ± 0.5 (mean ± s.e.m.) yr, and their percentage overweight was 42.9 ± 1.9%. Blood was drawn after an overnight fast. The age-matched control group consisted of 26 nonobese children, 13 boys and 13 girls. Plasma orexin-A concentration was higher in obese children (17.0 ± 0.4 pg/ml; p<0.001) than in the control children (13.5 ± 1.1 pg/ml). Similarly, plasma leptin concentration was higher in obese children (12.0 ± 1.0 ng/ml; p<0.001) than in the control children (5.2 ± 0.4 ng/ml). There was a highly significant positive correlation between the two parameters in the obese children (r=0.49, p<0.001). Plasma orexin-A level was correlated significantly with waist-to-hip ratio, while leptin level was correlated with percentage overweight, waist circumference and percentage body fat in the obese children. These results suggest that high plasma orexin-A level parallels the leptin level in obese children.

Stimulation of catecholamine synthesis by orexin-A in bovine adrenal medullary cells through orexin receptor 1.

Orexin-A has recently been identified as a new hypothalamic peptide working as a mediator in the regulation of feeding behavior and sleep control. To determine the role of orexin-A in peripheral metabolic processes, we examined direct effects of orexin-A on catecholamine synthesis and secretion in cultured bovine adrenal medullary cells. Incubation of cells with orexin-A (100 pM) for 20 min caused a small but significant increase in 14C-catecholamine synthesis from [14C]tyrosine, but not from L-3,4-dihydroxyphenyl[3-14C]alanine. Orexin-A (100 pM) potentiated the stimulatory effects of acetylcholine (0.3 mM) on 14C-catecholamine synthesis. Orexin-A significantly increased tyrosine hydroxylase activity, which was evident at 1 pM and maximal at 100 pM. 4 beta-Phorbol-12 beta-myristate-13 alpha-acetate, an activator of protein kinase C, did not enhance the stimulatory effects of orexin-A on tyrosine hydroxylase activity, while H-7 and staurosporine, inhibitors of protein kinase C, nullified the effects of orexin-A. Orexin-A had little effect on catecholamine secretion from the cells. Orexin receptor 1 (OX(1)R) but not orexin receptor 2 (OX(2)R) mRNA was detected in bovine adrenal medullary cells by reverse transcriptase-polymerase chain reaction. These findings suggest that orexin-A activates tyrosine hydroxylase and then stimulates catecholamine synthesis, probably via activation of the OX(1)R-protein kinase C pathway in adrenal medullary cells.