Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy.

Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities.

Modified setting of negative pressure in children with mild respiratory disease.

BACKGROUND: Continuous negative extra-thoracic pressure (CNEP) can prevent children with apnea developing severe respiratory infection with endotracheal intubation. Little is known about children with mild acute respiratory disease, especially with a focus on clinical respiratory symptoms. METHODS: We conducted a prospective, observational study between July 2014 and July 2017 to evaluate the safety of a modified setting of CNEP in hospitalized children with symptoms of chest-wall retraction or nasal alar breathing without the requirement for immediate intubation therapy in a single center. A modified setting of CNEP was defined as 4 h of treatment comprising 3 consecutive hours of CNEP followed by 1 h of rest. RESULTS: We studied 19 hospitalized children with retraction or nasal breathing but no possible state of endotracheal intubation. The median age at admission was 0.9 years and the duration of CNEP was 6 days. No sedative drugs were used. The percentage of children with retraction or nasal breathing after 24 h from initiation of CNEP was significantly decreased compared with that just before CNEP (68% vs 100%, P = 0.02). Logistic regression showed no statistical evidence of contributing factors for pulmonary symptoms. No patients were transferred to receive intubation, but one boy reinitiated respiratory support within 6 months after discharge. No children had adverse events of upper airway obstruction, skin injury, interfering with access, hypothermia, discomfort from fitting a cuirass, and neck excoriation. CONCLUSIONS: Our results suggest that a modified setting of CNEP management can be tolerated and continued without concern of adverse events.

Clinical spectrum of early onset epileptic encephalopathies caused by KCNQ2 mutation.

PURPOSE: KCNQ2 mutations have been found in patients with benign familial neonatal seizures, myokymia, or early onset epileptic encephalopathy (EOEE). In this study, we aimed to delineate the clinical spectrum of EOEE associated with KCNQ2 mutation. METHODS: A total of 239 patients with EOEE, including 51 cases with Ohtahara syndrome and 104 cases with West syndrome, were analyzed by high-resolution melting (HRM) analysis or whole-exome sequencing. Detailed clinical information including electroencephalography (EEG) and brain magnetic resonance imaging (MRI) were collected from patients with KCNQ2 mutation. KEY FINDINGS: A total of nine de novo and one inherited mutations were identified (two mutations occurred recurrently). The initial seizures, which were mainly tonic seizures, occurred in the early neonatal period in all 12 patients. A suppression-burst pattern on EEG was found in most. Only three patients showed hypsarrhythmia on EEG; eight patients became seizure free when treated with carbamazepine, zonisamide, phenytoin, topiramate, or valproic acid. Although the seizures were relatively well controlled, moderate-to-profound intellectual disability was found in all except one patient who died at 3 months. SIGNIFICANCE: De novo KCNQ2 mutations are involved in EOEE, most of which cases were diagnosed as Ohtahara syndrome. These cases showed distinct features with early neonatal onset, tonic seizures, a suppression-burst EEG pattern, infrequent evolution to West syndrome, and good response to sodium channel blockers, but poor developmental prognosis. Genetic testing for KCNQ2 should be considered for patients with EOEE.

Serum interleukin-18 level as a possible early diagnostic marker of systemic juvenile idiopathic arthritis.

Early diagnosis of systemic juvenile idiopathic arthritis (s-JIA) is a prerequisite for therapeutic efficacy. However, it is often challenging because most patients with s-JIA do not show arthritis at disease onset and are simply diagnosed with fever of unknown origin. Serum ferritin levels have commonly been used to diagnose s-JIA because they increase in patients with this condition by more than 5 times their normal value. However, there are no definite biomarkers for s-JIA, which makes the clinical diagnosis of s-JIA difficult. We report a case of s-JIA in which interleukin (IL)-18 elevation was observed before ferritin elevation at the early phase of s-JIA. We propose serum IL-18 levels as a more useful biomarker for the early diagnosis of s-JIA compared to serum ferritin levels.

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.

Familial cases of periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis syndrome.

We report three familial cases of periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis syndrome, including a pair of monozygotic twins and their mother. It suggests that periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis syndrome may have a certain monogenetic background.

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.

[Efficacy of topiramate in childhood epilepsies].

To evaluate the efficacy of topiramate (TPM) for the treatment of children with epilepsies, we introduced TPM to 45 patients whose epilepsy began in childhood and whose ages ranged from 4 months to 30 years old (mean age: 11 years 7 months). Thirteen of these patients had been diagnosed with generalized epilepsy (GE) (1 cryptogenic, 12 symptomatic), 30 with localization-related epilepsy (LRE) (7 idiopathic, 23 symptomatic), and 2 with unclassified epilepsy [1 case of severe myoclonic epilepsy in infancy (SMEI), 1 case of epilepsy with continuous spikes and waves during slow sleep (CSWS)]. The initial dose of TPM was 1.97 +/- 0.45 mg/kg/day, followed by a slow titration to the maximum dose of 7.32 +/- 1.32 mg/kg/day. After a mean treatment period of 13.5 months (range 4-20 months), the rate of reduction in seizure frequency by more than 50% [50% responder rate (50% RR)] and the rate of complete remission (seizure-free) were 53.8% and 23.1%, respectively, in patients with GE, and 73.3% and 23.3%, respectively, in patients with LRE. TPM was significantly effective against many seizure types including tonic, clonic, complex partial, myoclonic, and atypical absence seizures. Adverse effects included sleepiness in 13 cases (28.9%), weight loss in 6 cases (13.3%), and metabolic acidosis in 2 cases (4.4%); all of these effects were both mild and transient. In conclusion, TPM is effective and safe for the treatment of pediatric epilepsies.

Clinical time course of pediatric acute disseminated encephalomyelitis.

The detailed clinical time course in acute disseminated encephalomyelitis (ADEM) from initial symptoms, through exacerbation, to remission has not been widely reported. Hence, this study aimed to investigate the clinical time course of pediatric ADEM. This was a multicenter retrospective study based on registry data from medical chart reviews. The study included children who met the international consensus diagnostic criteria for ADEM. The patients comprised 18 boys and 6 girls, with a mean age of 5.5 ±â€¯3.3 years at onset. From onset, the time until peak neurological symptoms, time until initial improvement, and time until full recovery was 3.1 ±â€¯3.7 days, 6.0 ±â€¯4.5 days, and 26 ±â€¯34 days, respectively. Twenty-three (96%) patients were treated with high-dose methylprednisolone (mPSL) with a mean duration of 4.1 ±â€¯4.0 days from onset. The condition of 15 patients (65%) improved within 3 days of high-dose mPSL initiation, whereas, that of four patients began to improve after >5 days of high-dose mPSL initiation. Only one patient (4%) did not achieve full recovery despite treatment with high-dose mPSL, intravenous immunoglobulin, and plasma exchange. This study presents the detailed clinical time course in pediatric ADEM in Japan. Progression of neurologic deficits typically lasts a few days, with initial improvement in 1 week leading to full recovery within 1 month.

Two novel missense mutations in the myostatin gene identified in Japanese patients with Duchenne muscular dystrophy.

BACKGROUND: Myostatin is a negative regulator of skeletal muscle growth. Truncating mutations in the myostatin gene have been reported to result in gross muscle hypertrophy. Duchenne muscular dystrophy (DMD), the most common lethal muscle wasting disease, is a result of an absence of muscle dystrophin. Although this disorder causes a rather uniform pattern of muscle wasting, afflicted patients display phenotypic variability. We hypothesized that genetic variation in myostatin is a modifier of the DMD phenotype. METHODS: We analyzed 102 Japanese DMD patients for mutations in the myostatin gene. RESULTS: Two polymorphisms that are commonly observed in Western countries, p.55A>T and p.153K>R, were not observed in these Japanese patients. An uncommon polymorphism of p.164E>K was uncovered in four cases; each patient was found to be heterozygous for this polymorphism, which had the highest frequency of the polymorphism observed in the Japanese patients. Remarkably, two patients were found to be heterozygous for one of two novel missense mutations (p.95D>H and p.156L>I). One DMD patient carrying a novel missense mutation of p.95D>H was not phenotypically different from the non-carriers. The other DMD patient was found to carry both a novel mutation (p.156L>I) and a known polymorphism (p.164E>K) in one allele, although his phenotype was not significantly modified. Any nucleotide change creating a target site for micro RNAs was not disclosed in the 3' untranslated region. CONCLUSION: Our results indicate that heterozygous missense mutations including two novel mutations did not produce an apparent increase in muscle strength in Japanese DMD cases, even in a patient carrying two missense mutations.

Clinical features in very early-onset demyelinating disease with anti-MOG antibody.

BACKGROUND: The clinical features of patients with very early-onset acquired demyelinating syndrome (ADS) with the anti-myelin oligodendrocyte glycoprotein (MOG) antibody are unknown. We investigated the clinical characteristics and described detailed treatment of weekly intramuscular interferon ß-1a (IFNß-1a) in children aged <4years with ADS and the anti-MOG antibody. METHODS: We conducted a retrospective chart review of patients with anti-MOG positivity who were diagnosed as having multiple sclerosis (MS) at <4years of age. RESULTS: Subjects comprised 2 boys and 2 girls. Initial symptoms included ataxia, facial paresis, status epilepticus, and encephalopathy. Abnormal lesions on magnetic resonance imaging scans were often detected in the brainstem and cerebellum as well as the cerebrum. All patients started receiving IFNß-1a at age 3.1-3.5years. The initial doses ranged from 3 to 6µg, which were 1/10-1/5 doses, respectively, for adults. During 0.6-4.3years of IFNß-1a administration, all patients had flu-like symptoms, and 1 patient had an increased liver enzyme level. Although 1 patient discontinued IFNß-1a therapy because of frequent relapses, no patient discontinued therapy due to severe adverse events. CONCLUSIONS: This case series adds novel information regarding the clinical features of children <4years old with ADS and the anti-MOG antibody.

Clinical prediction rule for neurological sequelae due to acute encephalopathy: a medical community-based validation study in Harima, Japan.

OBJECTIVES: This study aimed to verify the screening performance of our clinical prediction rule for neurological sequelae due to acute encephalopathy (NSAE-CPR), which previously identified the following three variables as predictive of poor outcomes: (1) refractory status epilepticus; (2) consciousness disturbance and/or hemiplegia at 6 hours from onset and (3) aspartate aminotransferase >90 IU/L within 6 hours of onset. DESIGN: Medical community-based multicentre retrospective cohort study. SETTING: Six regional hospitals in Harima and one tertiary centre in Kobe, Japan, from 2008 to 2012. PARTICIPANTS: We enrolled a total of 1612 patients aged <16 years who met the diagnostic criteria for an initial diagnosis of complex febrile seizure. Patients with a history of neurological disease and those included in the derivation cohort were excluded. PRIMARY OUTCOME MEASURES: Univariate and multivariate analyses were performed to determine the association between each of the three predictor variables and poor AE outcome (Pediatric Cerebral Performance Category score ≥2). Receiver operating characteristic curve (ROC) analysis was also performed to assess the screening performance of the NSAE-CPR. RESULTS: The ROC analysis identified at least one of the three predictive variables as an optimal cut-off point, with an area under the curve of 0.915 (95% CI 0.825 to 1.000). The sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios and Matthews correlation coefficient were 0.867, 0.954, 0.149, 0.999, 18.704, 0.140 and 0.349, respectively. CONCLUSIONS: Our findings indicate that the NSAE-CPR can be used for the screening and identification of patients with poor outcomes due to acute encephalopathy within 6 hours of onset.

Genotype-phenotype correlations in alternating hemiplegia of childhood.

OBJECTIVE: Clinical severity of alternating hemiplegia of childhood (AHC) is extremely variable. To investigate genotype-phenotype correlations in AHC, we analyzed the clinical information and ATP1A3 mutations in patients with AHC. METHODS: Thirty-five Japanese patients who were clinically diagnosed with AHC participated in this study. ATP1A3 mutations were analyzed using Sanger sequencing. Detailed clinical information was collected from family members of patients with AHC and clinicians responsible for their care. RESULTS: Gene analysis revealed 33 patients with de novo heterozygous missense mutations of ATP1A3: Glu815Lys in 12 cases (36%), Asp801Asn in 10 cases (30%), and other missense mutations in 11 cases. Clinical information was compared among the Glu815Lys, Asp801Asn, and other mutation groups. Statistical analysis revealed significant differences in the history of neonatal onset, gross motor level, status epilepticus, and respiratory paralysis in the Glu815Lys group compared with the other groups. In addition, 8 patients who did not receive flunarizine had severe motor deteriorations. CONCLUSIONS: The Glu815Lys genotype appears to be associated with the most severe AHC phenotype. Although AHC is not generally seen as a progressive disorder, it should be considered a disorder that deteriorates abruptly or in a stepwise fashion, particularly in patients with the Glu815Lys mutation.

A case of anti-GA1 antibody-positive Fisher syndrome with elevated tau protein in cerebrospinal fluid.

We describe a boy with Fisher syndrome. He presented the typical symptoms of Fisher syndrome, including external ophthalmoplegia, abnormality of convergence, and areflexia, after an episode of Campylobacter enterocolitis. Atypically, however, anti-GA1 antibody was detected in his serum, though anti-GQ1b and anti-GT1a antibodies were not. In addition, the tau protein level in his cerebrospinal fluid was elevated. Generally, Fisher syndrome is a self-limiting disease and has a good prognosis. In our patient, however, mild diplopia and areflexia persisted 6 months after their onset. Here, we report on the first Fisher syndrome patient with anti-GA1 antibody in the serum and elevated tau protein in the cerebrospinal fluid.

Molecular analysis of TSC2/PKD1 contiguous gene deletion syndrome.

BACKGROUND: Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in either of two genes, TSC1 and TSC2. Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in either PKD1 or PKD2. TSC2 lies immediately adjacent to PKD1 and large heterozygous deletions can result in the TSC2/PKD1 contiguous gene syndrome (PKDTS). PKDTS has been identified in patients with TSC and early-onset severe ADPKD. However, genetic diagnosis with conventional methods proved to be difficult because its genetic aberrations are large monoallelic mutations. METHODS: In the study presented here, we used both multiplex ligation-dependent probe amplification (MLPA) and array comparative genomic hybridization (array-CGH) for four PKDTS patients. RESULTS: We were able to detect large heterozygous deletions including TSC2 and PKD1 by both of MLPA and array-CGH in all four patients. And in two patients, array-CGH identified relatively large genomic aberrations (RAB26, NTHL1, etc.), that extended outside of TSC2 or PKD1. CONCLUSION: The identical results obtained with these two completely different methods show that both constitute highly reliable strategies. Only a few studies have determined the breakpoints of large deletions in this disease and ours is the first to have identified the breakpoints by using array-CGH. We suggest that these methods are not only useful for the diagnosis of PKDTS but also for elucidation of its molecular mechanism.

Identification of seven novel cryptic exons embedded in the dystrophin gene and characterization of 14 cryptic dystrophin exons.

The dystrophin gene, which is mutated in Duchenne and Becker muscular dystrophy, is characterized by its extremely large introns. Seven cryptic exons from the intronic sequences of the dystrophin gene have been shown to be inserted into the processed mRNA. In this study, we have cloned seven novel cryptic exons embedded in dystrophin introns that were amplified from dystrophin mRNA isolated from lymphocytes. All of these sequences, which ranged in size from 27 to 151 bp, were found to be cryptic exons because they were completely homologous to intronic sequences (introns 1, 18, 29, 63, 67, and 77), and possessed consensus sequences for branch points, splice acceptor sites, and splice donor sites. Compared with the 77 authentic dystrophin exons, the 14 cryptic exons were characterized by (1) lower Shapiro's splicing probability scores for the splice donor and acceptor sites; (2) smaller and larger densities of splicing enhancer and silencer motifs, respectively; (3) a longer distance between the putative branch site and the splice acceptor site; and (4) with one exception, the introduction of premature stop codons into their respective transcripts. These characteristics indicated that the cryptic exons were weaker than the authentic exons. Our results suggested that a mutation deep within an intron that changed these parameters could cause dystrophinopathy. The cryptic exons identified provide areas that should be examined for the detection of mutations in the dystrophin gene, and they may help us to understand the roles of large dystrophin introns.