Search

Objectives Iodine deficiency and excess both cause thyroid dysfunction. Few data describe the relationship between iodine status and outcomes of congenital hypothyroidism (CH) in iodine-sufficient areas. We investigated urinary iodine (UI) concentration and its relationship with the clinical course of CH. Methods We reviewed and retrospectively analyzed patients with positive newborn screening (NBS) for CH from January 2012 to June 2019 in Japan, obtaining UI and UI-urine creatinine ratio (UI/Cr), serum TSH, free T4, free T3 and thyroglobulin (Tg) at the first visit, TSH at NBS, levothyroxine (LT4) dose, and subsequent doses. A UI value of 100–299 μg/L was considered adequate. Results Forty-eight patients were included. Median UI and UI/Cr were 325 μg/L and 3,930 µg/gCr, respectively. UI was high (≥300 μg/L) in 26 (54%) and low (≤99 μg/L) in 11 (23%). LT4 was administered to 34 patients. Iodine status was not related to the need for treatment. We found a U-shaped relationship between Tg and UI/Cr. Patients with high Tg (≥400 ng/mL) and abnormal UI levels required significantly lower LT4 doses (≤20 µg/day) at three years of age. Even if they showed severe hypothyroidism initially, they did not need subsequent dose increments. Conclusions Abnormal UI levels with Tg elevation were associated with lower LT4 dose requirements. The evaluation of iodine status and Tg concentrations were considered useful in patients suspected of CH.

The circadian clock network is an evolutionarily conserved system that regulates systemic metabolism, such as glucose homeostasis. Intestinal tissue is a pivotal organ for the regulation of glucose metabolism, mainly via glucose absorption into the circulation; however, the significance of the intestinal circadian clock network for glucose metabolism remains largely unclear. We herein utilized a mouse model in which Bmal1, a core clock gene, was deleted in an intestine-specific manner (Bmal1Int–/– mice) and demonstrated a rhythmic expression of Sglt1 with its peak at zeitgeber time (ZT) 10.7 ± 2.8 in control mice, whereas this was lost in Bmal1Int–/– mice. Mechanistically, chromatin immunoprecipitation analysis revealed rhythmic binding of CLOCK to the E-box elements in the Sglt1 gene in control mice; however, this was absent in Bmal1Int–/– mice. Accordingly, SGLT1 protein levels were decreased during the dark phase in Bmal1Int–/– mice and this was associated with impaired glucose absorption, leading to a decline in hepatic glycogen levels at ZT4, which was restored by ingestion of high-sucrose water. Additionally, when mice were starved from ZT0, greater expression of the lipolysis-related gene Pnpla2 was observed in adipose tissue of Bmal1Int–/– mice, and this was not noted when glycogen storage was restored by high-sucrose water prior to fasting, suggesting that higher Pnpla2 expression in Bmal1Int–/– mice was likely caused by lower glycogen storage. These results indicate that disruption of the intestinal circadian clock system impairs glucose absorption in the intestine and affects systemic glucose homeostasis.

Herein, we report two girls with a neonatal screening (NS)-negative 21-hydroxylase deficiency (21-OHD) requiring treatment with hydrocortisone due to virilization that developed in late childhood. Patient 1 was born prematurely on the 30th gestational week with normal external genitalia at birth. She passed the NS for 21-OHD. At 6 yr of age, she was referred to a hospital for evaluation of premature pubarche and clitoromegaly. Her diagnosis was central precocious puberty, and GnRH agonist was initiated. However, her symptoms did not improve despite treatment for over 4 years. She was then referred to our hospital where she was diagnosed with 21-OHD. Although she was started on hydrocortisone therapy, her adult height reached only 140 cm (−3.4 SD). Patient 2 was delivered at 37 weeks of gestation and passed the NS for 21-OHD. She was referred to a hospital because of premature pubarche at the age of 6 yr. She was diagnosed with 21-OHD, and hydrocortisone replacement therapy was initiated. Her present height at 13 yr of age is 148 cm (−1.3 SD). These cases reminded us that the possibility of 21-OHD should be considered when patients show premature pubarche or precocious puberty, even if they passed the NS test for 21-OHD.

The effectiveness of growth hormone (GH) treatment for height gain in short-stature children born small for gestational age (SGA) with extremely low birthweight (ELBW; birthweight1,000 g) remains largely unknown.In study 1, 35 prepubertal Japanese children born SGA with ELBW were categorized into three groups based on the presence or absence of catch-up growth by age 3 (CU(+) and CU(-), respectively) and GH treatment (GH(+) and GH(-), respectively). Height standard deviation (SD) scores (HT-SDS) in the CU-/GH+ group (n = 19) were compared with those in the age-matched CU+/GH- (n = 9) and CU-/GH- groups (n = 7). In study 2, 66 prepubertal Japanese SGA children treated with GH were divided into three groups by birthweight:1,000 g (n = 19), 1,000-2,000 g (n = 20), and2,000 g (n = 27). Changes in HT-SDS during the initial 3 years of GH treatment were compared among the three groups.In study 1, the mean HT-SDS in the CU-/GH+ group (-1.15 SD) was similar to that in the CU+/GH- group (-1.39 SD) but higher than that in the CU-/GH- group (-2.24 SD). In study 2, GH achieved a height gain of +1.62 SD in the ELBW group, which was similar to that in the other groups (1,000-2,000 g: +1.46 SD,2,000 g: +1.53 SD).Growth hormone treatment in short-stature children born SGA with ELBW increased HT-SDS, which was similar to that in SGA children born with a birthweight ≥1,000 g. These results indicate that GH treatment may be an effective approach to promote adequate growth recovery for short-stature children born SGA with ELBW.

MIRAGE syndrome is a recently identified disorder characterized by myelodysplasia, infection, restriction of growth, adrenal hypoplasia, genital phenotypes, and enteropathy. It is caused by a gain-of-function variant in the SAMD9 gene, but there is limited knowledge regarding the genotype–phenotype correlation. We herein report a Japanese patient with MIRAGE syndrome carrying a novel de novo heterozygous missense variant in the SAMD9 gene (c.4435 G > T; p.Ala1479Ser).

Background Children born small for gestational age (SGA) with catch-up growth are at high risk for developing obesity; however, the characteristics of body composition, especially fat distribution, before and after growth hormone (GH) treatment in SGA children without catch-up growth remains largely unknown. Methods Anthropometric characteristics, body composition by dual-energy X-ray absorption, and fat distribution by computed tomography at the umbilical level were examined in 27 prepubertal short-stature children born SGA before and 1 year after GH treatment. Results Before GH treatment, short-stature SGA children had lean phenotypes, and both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were significantly lower than the age- and sex-matched Japanese reference values. Growth hormone treatment significantly increased height standard deviation scores (SDS), without affecting body mass index SDS. Percentage fat mass decreased with GH treatment; however, fat mass was not altered. Both VAT and SAT were significantly lower than the reference values after GH treatment. The ratio of VAT over SAT significantly increased by GH treatment. Conclusions Both VAT and SAT were within or below the age- and sex-matched Japanese reference values in short-stature children born SGA before and after GH treatment, indicating that GH treatment may not have unfavorable effects on adiposity in short-stature children born SGA, although it may alter fat distribution.

MIRAGE syndrome is a recently identified disorder characterized by myelodysplasia, infection, restriction of growth, adrenal hypoplasia, genital phenotypes, and enteropathy. It is caused by a gain-of-function variant in the SAMD9 gene, but there is limited knowledge regarding the genotype–phenotype correlation. We herein report a Japanese patient with MIRAGE syndrome carrying a novel de novo heterozygous missense variant in the SAMD9 gene (c.4435 G > T; p.Ala1479Ser).

Selenium (Se) is an essential trace element that is involved in numerous biological processes in the form of a selenoprotein such as iodothyronine deiodinase (DIO). Se deficiency may prevent the conversion of T4 to T3 through reducing DIO expression and thereby affecting thyroid hormone status. However, this has not been well documented in humans. In this study, to clarify the association between Se and thyroid hormone status, we investigated the thyroid hormone levels in patients with severe Se deficiency (< 2 µg/dl). Severe Se deficiency was associated with increases in free T4 levels, but not with decreases and increases in free T3 and thyroid stimulating hormone (TSH) levels, respectively. Increases in free T4 levels during Se deficiency were reduced with Se supplementation; however, neither free T3 nor TSH levels were affected. Taken together, these findings indicate that free T4 may be a useful biomarker for Se status when serum Se levels are severely low.

Background Despite the presence of ganglion cells in the rectum, some patients have symptoms similar to those of Hirschsprung's disease. A consensus has yet to be established regarding the terminology for these diseases. We defined this group of diseases as "allied disorders of Hirschsprung's disease" and compiled these guidelines to facilitate accurate clinician diagnosis and provide appropriate treatment strategies for each disease. Methods These guidelines were developed using the methodologies in the Medical Information Network Distribution System (MINDS). Of seven allied disorders, isolated hypoganglionosis; megacystis-microcolon-intestinal hypoperistalsis syndrome; and chronic idiopathic intestinal pseudo-obstruction were selected as targets of clinical questions (CQ). In a comprehensive search of the Japanese- and English-language articles in PubMed and Ichu-Shi Web, 836 pieces of evidence related to the CQ were extracted from 288 articles; these pieces of evidence were summarized in an evidence table. Results We herein outline the newly established Japanese clinical practice guidelines for allied disorders of Hirschsprung's disease. Given that the target diseases are rare and intractable, most evidence was drawn from case reports and case series. In the CQ, the diagnosis, medication, nutritional support, surgical therapy, and prognosis for each disease are given. We emphasize the importance of full-thickness intestinal biopsy specimens for the histopathological evaluation of enteric ganglia. Considering the practicality of the guidelines, the recommendations for each CQ were created with protracted discussions among specialists. Conclusions Clinical practice recommendations for allied disorders of Hirschprung's disease are given for each CQ, along with an assessment of the current evidence. We hope that the information will be helpful in daily practice and future studies.