The Combination of Binding Avidity of Ovomucoid-Specific IgE Antibody and Specific IgG4 Antibody Can Predict Positive Outcomes of Oral Food Challenges during Stepwise Slow Oral Immunotherapy in Children with Hen's Egg Allergy.

To increase the prediction accuracy of positive oral food challenge (OFC) outcomes during stepwise slow oral immunotherapy (SS-OIT) in children with a hen's egg (HE) allergy, we evaluated the predictive value of the combination of antigen-specific IgE (sIgE) with antigen binding avidity and sIgG4 values. Sixty-three children with HE allergy undergoing SS-OIT were subjected to repeated OFCs with HE. We measured the ovomucoid (OVM)-sIgE by ImmunoCAP or densely carboxylated protein (DCP) microarray, sIgG4 by DCP microarray, and the binding avidity of OVM-sIgE defined as the level of 1/IC50 (nM) measured by competitive binding inhibition assays. The OFC was positive in 37 (59%) patients undergoing SS-OIT. Significant differences in DCP-OVM-sIgE, CAP-OVM-sIgE, I/IC50, DCP-OVM-sIgG4, the multiplication products of DCP-OVM-sIgE, and the binding avidity of DCP-OVM-sIgE (DCP-OVM-sIgE/IC50) and DCP-OVM-sIgE/sIgG4 were compared between the negative and positive groups (p < 0.01). Among them, the variable with the greatest area under the receiver operating characteristic curve was DCP-OVM-sIgE/IC50 (0.84), followed by DCP-OVM-sIgE/sIgG4 (0.81). DCP-OVM-sIgE/IC50 and DCP-OVM-sIgE/sIgG4 are potentially useful markers for the prediction of positive OFCs during HE-SS-OIT and may allow proper evaluation of the current allergic status in the healing process during HE-SS-OIT.

Temporary Renal Enlargement in Children with a First Episode of Febrile Urinary Tract Infection is a Significant Risk of Recurrent Infection.

PURPOSE: Although morphological renal abnormalities in children with febrile urinary tract infection (fUTI) have been showed a predictive factor for recurrent infection, there are no available data on recurrence regarding sonographic renal enlargement at first fUTI episode, especially focusing on whether renal enlargement is temporary or not. MATERIALS AND METHODS: This cohort study reviewed the medical records of children who underwent renal ultrasound during their first fUTI during 2005-2013 and who were aged <15 years at diagnosis. We defined a kidney as temporary enlarged when the kidney length was ≥2 standard deviation above normal renal length for that age on sonography or a difference of ≥1 cm in sonographic length between the right and left kidneys, following normal renal length after antibiotic treatment. RESULTS: A total of 132 children were enrolled, of whom 11 had sonographic temporary temporal renal enlargement during their first fUTI. After completing antibiotic therapy for a first fUTI episode, 20 (15%) children had fUTI recurrence. The clinical characteristics at first episode of fUTI were not significantly different between renal enlargement and nonrenal enlargement groups. Children with temporary renal enlargement at a first fUTI episode had significantly lower fUTI recurrence-free survival proportion than those with nonrenal enlargement according to the Kaplan-Meier method (p = 0.003) Conclusion: Identification of temporary temporal renal enlargement as a predictor of recurrent fUTI may help identify children with a first episode of fUTI who will be warned of close monitoring.

Predictive factors of continuous negative extrathoracic pressure management failure in children with moderate to severe respiratory syncytial virus infection.

Continuous negative extrathoracic pressure (CNEP) might be beneficial for children with severe respiratory tract infections. However, there are no available data on the predictors of its failure among individuals with respiratory syncytial virus (RSV) infections. Here, we conducted a retrospective cohort study between October 1, 2015 and October 31, 2018 in hospitalized children with moderate to severe symptoms of respiratory syncytial virus (RSV) infections. We divided 45 children requiring CNEP ventilation with a non-fluctuating negative pressure of - 12 cm H2O into two groups. They were classified based on improvement or deterioration of their respiratory disorder under CNEP ventilation (responder group: n = 27, failure group: n = 18). Based on the univariate analysis, the responder and failure groups significantly differed in terms of median age, days elapsed from RSV onset to the initiation of CNEP, white blood cell count (WBC), titer of venous pCO2, body temperature at admission, and modified Wood-Downes Score (mWDS) 6 h after initiating CNEP. Based on a logistic regression analysis adjusted for age < 1 year upon admission, less than 5 days elapsed from RSV onset to the initiation of CNEP, not high value of WBC and body temperature at admission, and high values of mWDS 6 h after initiating CNEP were found to be significant independent risk factors for CNEP ventilation failure. The former two variables were associated with less failure (odds ratio was approximately 5), and the latter two variables are associated with more failure (odds ratio was approximately 8-9). Thus, CNEP could be a valid option for children with moderate to severe RSV infections, especially in those who were aged > 1 year, and specific clinical and laboratory findings.

A Japanese child with geleophysic dysplasia caused by a novel mutation of FBN1.

Geleophysic dysplasia (GD) is a rare disorder characterized by severe short stature, short hands and feet, limited joint mobility, skin thickening, characteristic facial features (e.g., a "happy" face), and cardiac valvular disorders that often result in an early death. The genes ADAMTSL2 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif-like 2) and FBN1 (fibrillin 1) were recently identified as causative genes for GD. Here, we describe a 10-year-old Japanese female with GD who was born to non-consanguineous parents. At the age of 11 months, she was referred to our hospital because of very short stature for her age (-4.4 standard deviations of the age-matched value) and a "happy" face with full cheeks, a shortened nose, hypertelorism, and a long and flat philtrum, characteristic of GD. Her hands and feet were small, her skin was thickened, and her joint mobility was generally limited. She had cardiac valvular disorders and history of recurrent respiratory failure. Mutation analysis revealed no abnormalities in ADAMTSL2. However, analysis of FBN1 revealed a novel heterozygous mutation (c.5161T>T/G) in exon 41, which encodes transforming growth factor-ß-binding protein-like domain 5 (TB5). GD is an extremely rare disorder and, to our knowledge, only one case of GD with an FBN1 mutation has been reported in Japan. Similar to the previously reported cases of GD, the mutation in the current patient was located in the TB5 domain, which suggests that abnormalities in this domain of FBN1 are responsible for GD.

Treatment of preterm infants with West syndrome: differences due to etiology.

BACKGROUND: This study was conducted with a particular focus on preterm infants with West syndrome (WS) to evaluate differences in the first responses to oral medication based on etiology. METHODS: Medical records of 53 patients with WS, treated at five institutions between 2005 and 2009, were reviewed retrospectively. Patients were divided into six groups based on the time of brain insult, and evaluated for short-term outcomes using oral anti-epileptic agents and synthetic adrenocorticotropic hormone. RESULTS: The sample consisted of 15, six, 14, two, four, and 12 patients classified, on the basis of apparent time of acquisition of etiology, into the prenatal, term, preterm, postnatal, other, and no identified etiology groups, respectively. Average age of onset in the term group was 3.3 ± 1.0 months, significantly earlier than in the prenatal, preterm, postnatal and no identified etiology groups (P < 0.05). All patients in the term group had experienced seizures before the onset of WS. Only patients in the preterm group had only experienced neonatal seizures, and responded better to treatment. Patients in the preterm group had better responses to treatment, especially oral medication, compared with those in the prenatal and term groups. The prevalence of relapse of seizures in the preterm group (14%) was significantly lower than that in the prenatal group. CONCLUSIONS: Preterm WS patients responded well to treatment. Distinguishing WS patients on the basis of different etiologies is important for evaluating the effectiveness of treatment.

Molecular characterization of the 5'-UTR of retinal dystrophin reveals a cryptic intron that regulates translational activity.

PURPOSE: Mutations in the dystrophin (DMD) gene cause Duchenne or Becker muscular dystrophy (DMD/BMD). DMD contains a retina-specific promoter in intron 29. The short R-dystrophin transcript from this promoter has a retina-specific exon 1 (R1) joined to exon 30 of the DMD gene. It has been claimed that this is responsible for the ophthalmological problems observed in DMD/BMD. This research characterizes the structure of the 5'-untranslated region (5'-UTR) of human R-dystrophin. METHODS: The 5'-UTR of the human R-dystrophin transcript was amplified from human retina and 20 other human tissue RNAs by reverse transcription polymerase chain reaction (RT-PCR). Amplified products were identified by sequencing. The translational activities of transcripts bearing differing 5'-UTRs were measured using a dual luciferase assay system. RESULTS: RT-PCR amplification of the R-dystrophin transcript from the retina using a conventional primer set revealed one product comprising exon R1 and exons 30 to 32 (R-dys α). In contrast, three amplified products were obtained when a forward primer at the far 5'-end of exon R1 was employed for RT-PCR. R-dys α, and a shorter form in which 98 bp was deleted from exon R1 (R-dys ß), were the two major products. A minor, short form was also identified, in which 143 bp was deleted from exon R1 (R-dys γ). The two primary retinal products (R-dys α and ß) encoded an identical open reading frame. The 98 bp deleted in R-dys ß was identified as a cryptic intron that was evolutionarily acquired in higher mammals. The shorter R-dys ß was expressed in several tissues with a wide range in expression level, while R-dys α was retina specific. The 5'-UTRs of R-dys α and ß were examined for translational activity using a dual luciferase assay system. Unexpectedly, the 5'-UTR of R-dys ß showed lower translational activity than that of R-dys α. This lower activity was presumed to be due to the removal of internal ribosome entry sites by activation of cryptic intron splicing. CONCLUSIONS: An evolutionarily-acquired cryptic intron was identified in the 5'-UTR of the human R-dystrophin transcript. The two abundant R-dystrophin transcripts in the retina showed different translational activities in vitro owing to their differential splicing of the cryptic intron. This evolutionarily-acquired alternative splicing may act as a molecular switch that regulates translation of the R-dystrophin transcript.

Contemporary retrotransposition of a novel non-coding gene induces exon-skipping in dystrophin mRNA.

Non-autonomous retrotransposon-mediated mobilizations of the Alu family are known pathogenic mechanisms of human disease. Here, we report a pathogenic, contemporary, non-autonomous retrotransmobilization of part of a novel non-coding gene into the dystrophin gene. In a Japanese Duchenne muscular dystrophy patient, a 330-bp-long de novo insertion was identified in exon 67 of dystrophin. The insertion induced exon 67-skipping in the dystrophin mRNA, creating a premature stop codon. The sequence of the insertion had certain characteristics of retrotransposons: an antisense polyadenylation signal accompanied by a poly(T) sequence and a target site duplication. The insertion site matched the consensus recognition sequence for the L1 endonuclease, indicating a retrotransposon-mediated event, although the inserted sequence did not match any known retrotransposons. The origin of the inserted sequence was mapped to a gene-poor region of chromosome 11. The inserted fragment was expressed in multiple human tissue RNAs, indicating that it is a novel transcript. The full length of the transcript was cloned and showed no meaningful protein coding ability.

Mutation spectrum of the dystrophin gene in 442 Duchenne/Becker muscular dystrophy cases from one Japanese referral center.

Recent developments in molecular therapies for Duchenne muscular dystrophy (DMD) demand accurate genetic diagnosis, because therapies are mutation specific. The KUCG (Kobe University Clinical Genetics) database for DMD and Becker muscular dystrophy is a hospital-based database comprising 442 cases. Using a combination of complementary DNA (cDNA) and chromosome analysis in addition to conventional genomic DNA-based method, mutation detection was successfully accomplished in all cases, and the largest mutation database of Japanese dystrophinopathy was established. Among 442 cases, deletions and duplications encompassing one or more exons were identified in 270 (61%) and 38 (9%) cases, respectively. Nucleotide changes leading to nonsense mutations or disrupting a splice site were identified in 69 (16%) or 24 (5%) cases, respectively. Small deletion/insertion mutations were identified in 34 (8%) cases. Remarkably, two retrotransposon insertion events were also identified. Dystrophin cDNA analysis successfully revealed novel transcripts with a pseudoexon created by a single-nucleotide change deep within an intron in four cases. X-chromosome abnormalities were identified in two cases. The reading frame rule was upheld for 93% of deletion and 66% of duplication mutation cases. For the application of molecular therapies, induction of exon skipping was deemed the first priority for dystrophinopathy treatment. At one Japanese referral center, the hospital-based mutation database of the dystrophin gene was for the first time established with the highest levels of quality and patient's number.

Effect of CPS14217C>A genotype on valproic-acid-induced hyperammonemia.

BACKGROUND: In order to clarify the factors causing hyperammonemia and to predict occurrences during treatment with valproic acid (VPA), we investigated the effect of the genetic polymorphism of carbamoyl-phosphate synthase 1 (CPS14217C>A) on susceptibility of hyperammonemia, together with the effect of coadministration of other anticonvulsants. METHODS: Seventy-nine patients with epilepsy were enrolled, and five of them had hyperammonemia. Univariate and multivariate logistic regression analyses were performed. RESULTS: The aspartate aminotransferase level in the patients with hyperammonemia was significantly higher than that in those without hyperammonemia. The risk of hyperammonemia was significantly influenced by the number of anticonvulsants concomitantly administered with VPA. Also, the distribution of the CPS14217C>A genotype differed depending on whether the patients had hyperammonemia or not. No significant effects of CPS14217 genotypes and the number of anticonvulsants coadministered with VPA on the serum concentrations of VPA were observed. The multivariate logistic regression analysis showed that the concomitant administration of two or more anticonvulsants with VPA and the heterozygous or homozygous carrier state of the A allele of the CPS14217C>A polymorphism were independent risk factors for developing hyperammonemia. CONCLUSIONS: These findings suggested that in epileptic patients undergoing VPA therapy, CPS14217A polymorphism and the number of coadministered anticonvulsants would be considered as risk factors for hyperammonemia, even if the serum VPA concentrations were controlled.

Low incidence of limb-girdle muscular dystrophy type 2C revealed by a mutation study in Japanese patients clinically diagnosed with DMD.

BACKGROUND: Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive muscle dystrophy that resembles Duchenne muscular dystrophy (DMD). Although DMD is known to affect one in every 3500 males regardless of race, a widespread founder mutation causing LGMD2C has been described in North Africa. However, the incidence of LGMD2C in Japanese has been unknown because the genetic background remains uncharacterized in many patients clinically diagnosed with DMD. METHODS: We enrolled 324 patients referred to the Kobe University Hospital with suspected DMD. Mutations in the dystrophin or the SGCG genes were analyzed using not only genomic DNA but also cDNA. RESULTS: In 322 of the 324 patients, responsible mutations in the dystrophin were successfully revealed, confirming DMD diagnosis. The remaining two patients had normal dystrophin expression but absence of gamma-sarcoglycan in skeletal muscle. Mutation analysis of the SGCG gene revealed homozygous deletion of exon 6 in one patient, while the other had a novel single nucleotide insertion in exon 7 in one allele and deletion of exon 6 in the other allele. These mutations created a stop codon that led to a gamma-sarcoglycan deficiency, and we therefore diagnosed these two patients as having LGMD2C. Thus, the relative incidence of LGMD2C among Japanese DMD-like patients can be calculated as 1 in 161 patients suspected to have DMD (2 of 324 patients = 0.6%). Taking into consideration the DMD incidence for the overall population (1/3,500 males), the incidence of LGMD2C can be estimated as 1 per 560,000 or 1.8 per million. CONCLUSIONS: To the best of our knowledge, this is the first study to demonstrate a low incidence of LGMD2C in the Japanese population.

Insertion of the IL1RAPL1 gene into the duplication junction of the dystrophin gene.

Duplications of one or more exons of the dystrophin gene are the second most common mutation in dystrophinopathies. Even though duplications are suggested to occur with greater complexity than thought earlier, they have been considered an intragenic event. Here, we report the insertion of a part of the IL1RAPL1 (interleukin-1 receptor accessory protein-like 1) gene into the duplication junction site. When the actual exon junction was examined in 15 duplication mutations in the dystrophin gene by analyzing dystrophin mRNA, one patient was found to have an unknown 621 bp insertion at the junction of duplication of exons from 56 to 62. Unexpectedly, the inserted sequence was found completely identical to sequences of exons 3-5 of the IL1RAPL1 gene that is nearly 100 kb distal from the dystrophin gene. Accordingly, the insertion of IL1RAPL1 exons 3-5 between dystrophin exons 62 and 56 was confirmed at the genomic sequence level. One junction between the IL1RAPL1 intron 5 and dystrophin intron 55 was localized within an Alu sequence. These results showed that a fragment of the IL1RAPL1 gene was inserted into the duplication junction of the dystrophin gene in the same direction as the dystrophin gene. This suggests the novel possibility of co-occurrence of complex genomic rearrangements in dystrophinopathy.

Small mutations detected by multiplex ligation-dependent probe amplification of the dystrophin gene.

Currently, multiplex ligation-dependent probe amplification (MLPA) has been recognized as the most powerful and convenient method to identify exon deletions or duplications in the dystrophin gene, the mutation of which causes Duchenne and Becker muscular dystrophies (DMD/BMD). The mutation diagnosis is easily done by assessing the amounts amplified by MLPA (loss, single, or double). However, an ambiguous amount of amplified product has never been reported. When 77 Japanese DMD/BMD patients were examined by MLPA from MRC-Holland (Amsterdam, The Netherlands), deletions/duplications in the dystrophin gene were identified in 64.8%. Ten male patients showed loss of a single exon by MLPA, but one of them was found to have not an exon deletion, but a four-nucleotide deletion (c.3347-3350delAGAA) within the exon. Remarkably, two patients showed ambiguous amounts of product with less than half of that of a single copy, making the genetic diagnosis impossible. In one patient, a novel single-nucleotide change (c.4303G>T) leading to a nonsense mutation was identified. In another patient, a novel five-nucleotide deletion (c.4536-4540delGAGTG) was identified. It was considered that these two mutations partially disturbed MLPA amplification, resulting in ambiguous amplification. These results show that MLPA can serve as a tool for screening small mutations, as well as for detecting exon deletions or duplications.

Two Japanese infants with congenital generalized lipodystrophy due to BSCL2 mutations.

BACKGROUND: Congenital generalized lipodystrophy (CGL), Berardinelli-Seip syndrome, is a rare autosomal recessive disorder characterized by the generalized absence of adipose tissue at birth, severe insulin resistance early in life, hypertriglyceridemia, hepatomegaly, and the development of diabetes mellitus during puberty. Recently, two genes, BSCL2 and AGPAT2, were identified as causative genes for CGL. It has been reported that patients with BSCL mutations present with more severe clinical findings than those with AGPAT2 mutations. However, the clinical course of CGL caused by BSCL2 mutations in infancy has not been fully elucidated. METHODS: Two Japanese infantile patients with CGL from independent families were examined and underwent an oral glucose tolerance test. Insulin resistance and insulin secretion were estimated using the homeostasis model assessment for insulin resistance and the insulinogenic index, respectively. Sequence analysis of the entire coding region of BSCL2 and AGPAT2 was performed. RESULTS: Both CGL patients presented with normal glycemic profiles after oral glucose tolerance tests; however, the values from the homeostasis model assessment of insulin resistance were elevated and well above the cut-off point for diagnosis of infant insulin resistance in both patients. One patient possessed a known homozygous nonsense mutation in exon 8 (c.823C>T) of BSCL2; the other had a novel homozygous missense mutation in exon 5 (c.560A>G) of BSCL2. CONCLUSION: Japanese CGL patients with BSCL2 mutations presented with severe insulin resistance, even during infancy, prior to the development of diabetes mellitus.

Tandem duplications of two separate fragments of the dystrophin gene in a patient with Duchenne muscular dystrophy.

Mutations in the dystrophin gene result in the most common inherited muscle disease, Duchenne muscular dystrophy (DMD). Duplications spanning one or more exons have been found to be the second most common disease-causing mutation in the dystrophin gene. Although the duplicated exons are commonly thought to be arranged in tandem, rare noncontiguous exon duplications have been disclosed without clarifying their location or orientation. Here we present the first report that details the exact locations and orientations of noncontiguous duplications in the dystrophin gene. Multiplex ligation-dependent probe amplification analysis of the dystrophin gene of a Japanese boy with DMD revealed that his genomic DNA contained duplications of exons from two separate fragments of the gene: one from exon 45 to exon 48 and the other from exon 55 to exon 63. To clarify the locations and orientations of the duplicated exons, reverse transcription-nested PCR analysis of dystrophin mRNA was conducted. Interestingly, the extra copies of exons 45-48 and exons 55-63 were found to be properly oriented between exons 48 and 49 and exons 63 and 64, respectively. These results indicated that two tandem duplication events occurred in the dystrophin gene of this patient and should contribute to the understanding of the duplication mechanisms that contribute to the development of DMD.

Mutation analysis of the ornithine transcarbamylase (OTC) gene in five Japanese OTC deficiency patients revealed two known and three novel mutations including a deep intronic mutation.

Ornithine transcarbamylase (OTC) deficiency is the most common inborn error of the urea cycle. Although a combination of molecular methods have been used including DNA sequencing of all 10 exons and exon-intron boundaries of OTC gene, only approximately 80% of patients with OTC deficiency are found to have mutations. We report two known and three novel mutations of the OTC gene in five Japanese patients including two neonatal-onset, one late-onset, and two symptomatic female patients. Known nonsense mutations (c.578G>A and c.421C>T) were detected in a neonatal-onset male and a symptomatic female patient, respectively. Mutation analysis revealed two novel mutations including one splice site mutation (c.386+1G>C) in a symptomatic female patient and one missense mutation (c.515T>A) in a late-onset male patient. In the remaining case, which was a neonatal-onset male patient, no mutation was disclosed by direct sequencing of all 10 exons and their flanking intron sequences. Therefore, OTC mRNA in the liver was analyzed by RT-PCR, and remarkably, a 135-nt insertion was detected between exons 5 and 6. Genomic DNA analysis of intron sequences revealed a single nucleotide change at 265 bp downstream from the 3' end of exon 5, which created the novel splice acceptor site. Thereby, a 135-nt exon was created from the central part of an intron sequence. This is the first report of mutation deep in the intronic sequence in the OTC gene. Molecular analysis using genomic DNA and mRNA will increase the mutation detection ratio in the OTC gene.