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.

Various phenotypes of short stature with heterozygous IGF-1 receptor (IGF1R) mutations.

Type 1 insulin-like growth factor receptor (IGF1R) plays an important role in normal fetal and postnatal growth. Over 30 pathogenic variants of IGF1R have been identified in patients with short stature. Yet, 20 years after the first report, a variety of phenotypes remain poorly defined. We analyzed the genetic and clinical data and responses to GH therapy in 11 patients using results from questionnaires. Eight of the 11 patients have already been reported in previous articles, and all of the identified mutations were heterozygous. The patients exhibited various phenotypes. At least two patients did not meet the criteria for GH treatment for small for gestational age (SGA) short stature, and two more patients showed lower serum IGF1 levels. Nine of the 11 patients had thin upper lips. Five patients with heterozygous IGF1R treated with GH exhibited similar height gains to those reported in previous Japanese studies on SGA short stature, which also led to extremely high serum IGF1 levels. Patients with short stature due to IGF1R mutations exhibit various phenotypes. Their presentation at diagnosis may be indistinguishable from common short stature. More specific clinical scoring that considers elevated IGF1 levels after GH treatment is needed to better detect IGF1R mutations.

Results from 28 years of newborn screening for congenital adrenal hyperplasia in sapporo.

The primary goal of newborn mass screening (MS) for congenital adrenal hyperplasia (CAH) is the prevention of life-threatening salt-wasting crisis in the most severe forms of CAH, and MS for CAH has been implemented in several countries. We summarize here our experience and results from newborn CAH MS from 1982 to 2010 in Sapporo City. During these 28 yr, the level of 17-hydroxyprogesterone (17-OHP) was determined in MS of samples from 498,147 newborns. During this period, 26 individuals (19 females and 7 males) with 21-hydroxylase deficiency (21-OHD) were detected. Of the 26 CAH, 20 were classified as having the salt-wasting (SW) form, 4 were classified as having the simple virilizing (SV) form, and 2 were classified as having the noncalssic (NC) form. Therefore, the frequency of the classical type of CAH was 1 in 20,756. In order to improve the effectiveness, we employed high-performance liquid chromatography (HPLC) as a second tier test from 2000. During this period, among the recalled babies, 75.4% were born prior to the 37th wk of gestation age, and the recall rate was 5.38% for premature neonates and 0.06% for mature neonates. MS for CAH in Sapporo is effective for the identification of the SW and SV forms of 21-OHD. However, the recall rate of premature babies is still high after the introduction of HPLC as a second tier test.

Loss-of-function and gain-of-function mutations of calcium-sensing receptor: functional analysis and the effect of allosteric modulators NPS R-568 and NPS 2143.

OBJECTIVE: Activating mutations in the calcium-sensing receptor (CASR) gene cause autosomal dominant hypoparathyroidism, and heterozygous inactivating CASR mutations cause familial hypocalciuric hypercalcemia. Recently, there has been a focus on the use of allosteric modulators to restore the functional activity of mutant CASRs. In this study, the effect of allosteric modulators NPS R-568 and NPS 2143 on CASR mutants was studied in vitro. METHODS: DNA sequence analysis of the CASR gene was undertaken in autosomal dominant hypoparathyroidism and familial hypocalciuric hypercalcemia Japanese patients, and the functional consequences for the Gi-MAPK pathway and cell surface expression of CASR were determined. Furthermore, we studied the effect of NPS R-568 and NPS 2143 on the signal transduction activity and cell surface expression of each mutant CASR. RESULTS: We identified 3 activating mutations (S122C, P569H, and I839T) and 2 inactivating mutations (A110T and R172G) in patients. The activating and inactivating mutations caused leftward and rightward shifts, respectively, in the dose-response curves of the signaling pathway. NPS R-568 rescued the signal transduction capacity of 2 inactivating mutants without increasing cell surface expression levels. NPS 2143 suppressed the enhanced activity of the activating mutants without altering cell surface expression levels, although A843E, which is a constitutively active mutant, was suppressed to a lesser degree. CONCLUSIONS: We have identified 4 novel mutations of CASR. Moreover, our results indicate that allosteric modulators can restore the activity of the loss- and gain-of-function mutant CASRs, identified in this study.

Three novel IGSF1 mutations in four Japanese patients with X-linked congenital central hypothyroidism.

CONTEXT: Congenital central hypothyroidism (C-CH) is a rare disease. We investigated the molecular basis of unexplained C-CH in 4 Japanese boys. PATIENTS AND METHODS: C-CH was diagnosed by low free T4 and/or T3 and low basal TSH concentrations. We used whole-exome sequencing of one patient with C-CH to identify potential disease-causing mutations. Thereafter, PCR direct sequencing was performed to Identify genetic defects underlying C-CH in 3 more patients. We then assessed the effects of mutations identified in the Ig superfamily, member 1 (IGSF1), gene on protein expression and membrane trafficking. RESULTS: All patients had congenital hypothyroidism, and 2 had definitive prolactin deficiency. Two patients were detected by neonatal screening. The other patients were diagnosed by short stature and failure to thrive. We identified a novel nonsense variant in IGSF1 by whole-exome sequencing in patient 1, which was confirmed by PCR direct sequencing (p.R1189X). PCR direct sequencing identified the identical nonsense mutation in patient 2. Patients 3 and 4 harbored distinct missense (p.V1082E) or nonsense (p.Q645X) mutations in IGSF1. The mothers of patients 1, 3, and 4 were heterozygous for these mutations. The R1189X mutant, which lacks the transmembrane domain, failed to traffic to the plasma membrane. V1082E could be observed at the cell surface, but at greatly diminished levels relative to the wild-type form of the protein. The severely truncated Q645X mutant could not be detected by Western blot. CONCLUSION: Our findings provide additional genetic evidence that loss-of-function mutations in IGSF1 cause an X-linked form of C-CH and variable prolactin deficiency.

N-terminal pro-brain natriuretic Peptide as a useful diagnostic marker of acute Kawasaki disease in children.

BACKGROUND: Serum N-terminal pro-brain natriuretic peptide (NTproBNP) is often elevated in patients with acute Kawasaki disease (KD), but the NTproBNP level in normal children is higher than in adults. Thus, characterization of the normal levels and cut-off values of NTproBNP according to age is warranted for proper diagnosis of acute KD in children. METHODS AND RESULTS: Six hundred and fifty-five patients aged 1 month-15 years (median, 2.9 years) were included. Patients were admitted to the NTT East Japan Sapporo Hospital between October 2007 and October 2011. Serum NTproBNP level was examined in 149 patients with KD (median, 2.1 years) and 506 control patients with acute infectious disease (median, 3.2 years). In the control group, a Z-score curve of NTproBNP was generated for each age group using least mean square-based methods. The Z-score distribution of KD patients was then compared with that of the control group. The specificity and sensitivity of NTproBNP for diagnosing acute KD were 97.8% and 47.0%, respectively, at Z-score >2.0. Additionally, simple cut-offs every 100 pg/ml according to age were established for more convenient use at the bedside. CONCLUSIONS: The Z-score curve for NTproBNP in children was characterized. A Z-score >2.0 or the cut-off for children may be used to diagnose acute KD.

Investigation of iodine deficient state and iodine supplementation in patients with severe motor and intellectual disabilities on long-term total enteral nutrition.

Iodine concentrations of enteral nutrition (EN) formulae available in Japan are very low and long-term total EN (TEN) might result in hypothyroidism due to iodine deficiency (HID). Our aim of this study was to determine the degree of iodine deficiency (ID) and need for iodine supplementation (IS) in patients with severe motor and intellectual disabilities (SMID) on long-term TEN. Thyroid function including urinary iodine concentration (UIC) was monitored, and powdered kelp was provided as a source of iodine supplement. Thirty-five SMID on TEN participated in our study. UIC less than 100 µg /L, representing ID, were detected in 97 % of them. Their TSH ranged from 0.5 to 90 µIU/mL. IS using powdered kelp raised their UIC to the normal range. Thyroid function also recovered in the five hypothyroidism cases, which were diagnosed as HID, was also detected. In Japan, there must be many cases with ID associated with long term TEN. We also discuss the regulation of thyroid function in the iodine deficient state.

Neonatal screening for congenital adrenal hyperplasia in Japan.

A nationwide screening test for congenital adrenal hyperplasia (CAH) was first initiated in Japan in 1989, over 20 years ago, and it is now 30 years since a pilot study was initiated in Sapporo in 1982. The incidence of 21-hydroxylase deficiency in Japan is about 1/18,000 persons, which is similar to that in other countries. The effectiveness of early detection and treatment of CAH in Japan has been demonstrated by cost-benefit analyses. However, the false-positive rate of CAH screening in preterm infants remains high compared to screening tests for term infants. To improve the positive predictive value, we have employed 21-hydroxylase gene (CYP21A2) analysis on dried blood spots and high performance liquid chromatography (HPLC) to measure 17-hydroxyprogesterone, and currently use tandem mass spectrometry (LC-MS/MS) as a screening technique. We suggest that LC-MS/MS should be used in the future to improve the accuracy of CAH screening in Japan.

Clinical characteristics and computed tomography findings in children with 2009 pandemic influenza A (H1N1) viral pneumonia.

In this article we review the clinical characteristics and computed tomography (CT) findings in children with 2009 pandemic H1N1 influenza viral pneumonia. The medical charts of 88 children with pandemic H1N1 influenza virus infection, admitted to our hospital in Japan from 10 August to 28 December 2009, were reviewed; we compared the clinical features of these children with those of 61 children admitted with seasonal influenza A during the previous 3 seasons. Of 88 patients, 53 (60%) had radiographic findings consistent with pneumonia and 34 patients underwent a chest computed tomography (CT) scan. Pneumonia was a more frequent complication in children with pandemic H1N1 influenza compared with those with seasonal influenza (60% vs 11%; p < 0.001). The predominant CT findings were unilateral or bilateral multifocal consolidation (15/34; 44%) associated with ground-glass opacities in the peribronchovascular region. The second most common CT finding was unilateral diffuse consolidation or atelectasis in 1 or more lung zones (12/34; 35%). The chest CT findings of unilateral or bilateral multifocal consolidation often associated with ground-glass opacities were commonly seen in children with pandemic H1N1 influenza viral pneumonia. Atelectasis was seen in patients who required oxygen administration.

Treatment of Hypothyroidism due to Iodine Deficiency Using Daily Powdered Kelp in Patients Receiving Long-term Total Enteral Nutrition.

We investigated thyroid function and urinary iodine concentration (UIC) in seven patients with severe motor intellectual disabilities. All seven received total enteral nutrition (TEN) for more than three years with a daily iodine intake of less than 20 µg. They were diagnosed as hypothyroidism due to iodine deficiency (HID) because of high TSH levels (7.6-82.3 µIU/ml), lower free T4 (FT4 0.4-1.5 ng/dl), negative anti-thyroid antibodies (anti-thyroglobulin antibody, anti-thyroidal peroxidase antibody) and extremely low UIC (<25-58 µg/l) levels. We gave them 1-2 g powdered kelp (200-400 µg as iodine) once a day, which restored their thyroid function and normalized their UICs. We proposed that daily powdered kelp would be effective and safe to treat HID in patient receiving long term TEN.

Comparison of an immunochromatography test with multiplex reverse transcription-PCR for rapid diagnosis of respiratory syncytial virus infections.

A new commercial rapid 10-min one-step immunochromatography (IC) test, SAS RSV test, was compared to another IC test, Directigen EZ RSV, employing RT-PCR as the "gold standard" for detecting respiratory syncytial virus. Of 102 clinical samples, 79 were positive by RT-PCR, 66 (82.5%) were positive with the SAS RSV test, and 55 (69.6%) were positive with Directigen EZ RSV. The specificity of the new test was 91.3% (21 of 23), similar to that of Directigen EZ RSV (100% [23 of 23]). This test performs well enough to be used for patient care.

Etiological agents of lower respiratory tract infections in Japanese children.

To investigate the etiology of pediatric community-acquired pneumonia and bronchitis, we conducted a prospective, population-based study covering the total population < 15 years of age in 16 municipalities in Hokkaido, Japan, during the period of April 2000 to March 2001. Chest radiographs were available for all cases (n = 921; 398 as pneumonia and 523 as bronchitis) and paired sera for serologic assays were available for more than half of the cases. The following specimens were also collected: nasopharyngeal swabs for viral, bacteriological, mycoplasmal and chlamydial studies, blood for serology and blood culture. The children were then followed-up on days 3, 7 and 14. Specific infecting organisms were identified in a total of 853 (92.6%) out of 921 patients (398 cases of pneumonia and 523 cases of bronchitis) including 205 with mixed infection as follows: Mycoplasma pneumoniae, 252 (274%) patients; respiratory syncytial (RS) virus, 188 (20.4%); influenza A virus, 110 (11.9%); Streptococcus pneumoniae, 95 (10.3%); Haemophilus influenzae, 90 (9.8%); Haemophilus parainfluenzae, 35 (3.8%); Staphylococcus aureus, 29 (3.1%); adenovirus, 27 (2.9%); Moraxella catarrhalis, 12 (1.3%); Pseudomonas aeruginosa , 7 (0.8%); Chlamydia pneumoniae, 6 (0.7%); and other agents, 2 (0.2%). Mycoplasma infections were seen even in patients less than 5 years and RS and influenza A virus infections in patients more than 5 years of age. The importance of M. pneumoniae and RS virus in the etiology of lower respiratory infections in Japanese children was confirmed.