HECW2-related disorder in four Japanese patients.

The HECT, C2, and WW domain containing E3 ubiquitin protein ligase 2 gene (HECW2) is involved in protein ubiquitination. Several genes associated with protein ubiquitination have been linked to neurodevelopmental disorders. HECW2-related disorder has been established through the identification of de novo variants in HECW2 in patients with neurodevelopmental disorders with hypotonia, seizures, and absent language. Recently, we identified novel HECW2 variants in four Japanese patients with neurodevelopmental disorders. Regarding motor development, two of the patients cannot walk, whereas the other two can walk with an unsteady gait, owing to hypotonia. All HECW2 variants, including those that were previously reported, are missense, and no loss-of-function variants have been identified. Most of the identified variants are located around the HECT domain. These findings suggest that the dominant negative effects of missense variants around the HECT domain may be the mechanism underlying HECW2-related disorder.

Renal dysfunction is rare in Fukuyama congenital muscular dystrophy.

BACKGROUND: The leading cause of death in patients with Fukuyama congenital muscular dystrophy (FCMD) is congestive heart failure or respiratory dysfunction, which is same as that in Duchenne muscular dystrophy (DMD). Recent studies reported that renal dysfunction is a common complication and an increasing cause of death in advanced DMD. It can be attributable to circulatory instability or inappropriate use of drugs for treating cardiac dysfunction. METHODS: We retrospectively evaluated renal function in 38 genetically diagnosed patients with FCMD (range, 1.3-32.9 years; mean age, 13.7 ±â€¯6.9 years) using cystatin C. We examined possible relationships of cystatin C with blood natriuretic peptide and creatinine levels along with cardiac echocardiography findings. RESULTS: Twenty-five patients were treated for cardiac dysfunction. Elevated cystatin C level was detected only in two, who also showed proteinuria, glycosuria, hematuria, and extremely high ß2-microglobulin levels on urine tests, and were thus diagnosed with renal tubular cell damage. Because both patients were treated for intractable epilepsy with various antiepileptic drugs, including valproic acid (VPA), and had low serum carnitine levels, renal tubular cell damage was considered as an adverse effect of VPA. Unlike patients with DMD, no patient with FCMD had renal dysfunction. Such a rare occurrence of renal dysfunction can be attributable to mild cardiac dysfunction, short disease duration, and careful and early fluid management. CONCLUSION: Renal dysfunction is rare in patients with FCMD; however, renal tubular cell damage should be ascertained, particularly in those undergoing VPA treatment for epilepsy.

Aicardi-Goutières syndrome is caused by IFIH1 mutations.

Aicardi-Goutières syndrome (AGS) is a rare, genetically determined early-onset progressive encephalopathy. To date, mutations in six genes have been identified as etiologic for AGS. Our Japanese nationwide AGS survey identified six AGS-affected individuals without a molecular diagnosis; we performed whole-exome sequencing on three of these individuals. After removal of the common polymorphisms found in SNP databases, we were able to identify IFIH1 heterozygous missense mutations in all three. In vitro functional analysis revealed that IFIH1 mutations increased type I interferon production, and the transcription of interferon-stimulated genes were elevated. IFIH1 encodes MDA5, and mutant MDA5 lacked ligand-specific responsiveness, similarly to the dominant Ifih1 mutation responsible for the SLE mouse model that results in type I interferon overproduction. This study suggests that the IFIH1 mutations are responsible for the AGS phenotype due to an excessive production of type I interferon.

A nationwide survey of Aicardi-Goutières syndrome patients identifies a strong association between dominant TREX1 mutations and chilblain lesions: Japanese cohort study.

OBJECTIVES: Aicardi-Goutières syndrome (AGS) is a rare, genetically determined, early onset progressive encephalopathy associated with autoimmune manifestations. AGS is usually inherited in an autosomal recessive manner. The disease is rare, therefore the clinical manifestations and genotype-phenotype correlations, particularly with regard to autoimmune diseases, are still unclear. Here we performed a nationwide survey of AGS patients in Japan and analysed the genetic and clinical data. METHODS: Patients were recruited via questionnaires sent to paediatric or adult neurologists in Japanese hospitals and institutions. Genetic analysis was performed and clinical data were collected. RESULTS: Fourteen AGS patients were identified from 13 families; 10 harboured genetic mutations. Three patients harboured dominant-type TREX1 mutations. These included two de novo cases: one caused by a novel heterozygous p.His195Tyr mutation and the other by a novel somatic mosaicism resulting in a p.Asp200Asn mutation. Chilblain lesions were observed in all patients harbouring dominant-type TREX1 mutations. All three patients harbouring SAMHD1 mutations were diagnosed with autoimmune diseases, two with SLE and one with SS. The latter is the first reported case. CONCLUSION: This study is the first to report a nationwide AGS survey, which identified more patients with sporadic AGS carrying de novo dominant-type TREX1 mutations than expected. There was a strong association between the dominant-type TREX1 mutations and chilblain lesions, and between SAMHD1 mutations and autoimmunity. These findings suggest that rheumatologists should pay attention to possible sporadic AGS cases presenting with neurological disorders and autoimmune manifestations.

[A case of spinal muscular atrophy type 0 in Japan].

The patient was a 2-month-old female infant born at 41 weeks and 2 days of gestation presenting multiple arthrogryposis, severe muscle hypotonia and respiratory distress with difficulty in feeding. She suffered from repeated complications with aspiration pneumonia. On admission to our hospital, she exhibited fasciculation and absence of deep tendon reflexes. Examination of the motor nerve conduction velocity (MCV) revealed no muscle contraction. Deletions of the SMN and NAIP genes were noted. Based on severe clinical course and disease development in utero, she was given a diagnosis of spinal muscular atrophy (SMA) type 0 (very severe type). Arthrogryposis and disappearance of MCV are exclusion criteria for SMA. However, the clinical course of the infant was very severe and included such exclusion items. Consequently, when an infant presents muscle hypotonia and respiratory distress, SMA must be considered as one of the differential diagnoses, even though arthrogryposis is an exclusion criterion for SMA. We discuss this case in relation to the few extant reports on SMA type 0 in Japanese infants in the literature.

A loss-of-function mutation in the SLC9A6 gene causes X-linked mental retardation resembling Angelman syndrome.

SLC9A6 mutations have been reported in families in whom X-linked mental retardation (XMR) mimics Angelman syndrome (AS). However, the relative importance of SLC9A6 mutations in patients with an AS-like phenotype or XMR has not been fully investigated. Here, the involvement of SLC9A6 mutations in 22 males initially suspected to have AS but found on genetic testing not to have AS (AS-like cohort), and 104 male patients with XMR (XMR cohort), was investigated. A novel SLC9A6 mutation (c.441delG, p.S147fs) was identified in one patient in the AS-like cohort, but no mutation was identified in XMR cohort, suggesting mutations in SLC9A6 are not a major cause of the AS-like phenotype or XMR. The patient with the SLC9A6 mutation showed the typical AS phenotype, further demonstrating the similarity between patients with AS and those with SLC9A6 mutations. To clarify the effect of the SLC9A6 mutation, we performed RT-PCR and Western blot analysis on lymphoblastoid cells from the patient. Expression of the mutated transcript was significantly reduced, but was restored by cycloheximide treatment, indicating the presence of nonsense mediated mRNA decay. Western blot analysis demonstrated absence of the normal NHE6 protein encoded for by SLC9A6. Taken together, these findings indicate a loss-of-function mutation in SLC9A6 caused the phenotype in our patient.

Two cases of precocious puberty associated with hypothalamic hamartoma.

Hypothalamic hamartoma (HH) is a congenital malformation diagnosed based on magnetic resonance imaging (MRI) and histological findings; it is often associated with central precocious puberty (CPP), gelastic seizures, abnormal behavior and mental retardation. In the present paper, we report our retrospective hypothesis that there is a relationship between symptoms and therapy, as well as the treatment for HH, and describe two cases of HH associated with CPP. Both cases had sessile masses located in the interpeduncular cistern, with extension to the hypothalamus on MRI (1.2 × 1.5 cm and 2.0 × 2.5 cm, respectively). The first case had intractable seizures, while the second had no seizures with paroxysmal discharge. In both patients, the hamartomas were partially removed, by γ-knife and surgical operation in the first case and surgically in the second, and a gonadotropin releasing hormone (GnRH) analogue was prescribed. One case showed improvement of both intelligence quotient (IQ) score and seizures, and the other showed improvements in IQ and abnormal behavior. It was difficult to determine any topology/symptom relationships. Surgery and GnRH analogue treatment can alleviate seizures, abnormal behavior and mental retardation associated with HH.

Neurobehavioral abnormalities may correlate with increased seizure burden in children with Panayiotopoulos syndrome.

Prognostic factors for frequent seizure recurrences were studied in patients with Panayiotopoulos syndrome. The subjects were 79 children fulfilling the criteria of Panayiotopoulos syndrome who were monitored for longer than 2 years. Medical records and electroencephalograms were analyzed retrospectively. The total number of seizures in each patient at the final follow-up ranged from 1 to 22. The 79 patients were classified into three groups: typical Panayiotopoulos syndrome (seizure recurrence = 1-5 times, n = 45), borderline (6-9 times, n = 16), and atypical (>10 times, n = 18). Data analyzed included family history of seizure disorders, peri- and postnatal complications, previous seizure histories, age at epilepsy onset, clinical seizure manifestations, the frequency of status epilepticus, interictal electroencephalographic patterns, and the possible association of neurobehavioral disorders among the three groups. An association with pre-existing neurobehavioral disorders was significantly more frequent in the atypical than in the typical group (P < 0.05), but not significantly different between the typical and borderline or between the borderline and atypical patients (P> 0.05). In patients with Panayiotopoulos syndrome and pre-existing mild neurobehavioral disorders, seizures tend to be pharmacoresistant and to repeat more than 10 times. However, all patients experience seizure remission by 12 years of age, and should not be evaluated for surgery.

Differentiation of myoclonic seizures in epileptic syndromes: a video-polygraphic study of 26 patients.

OBJECTIVE: We conducted a video-polygraphic study of myoclonic seizures (MS) in different epileptic syndromes to clarify semiologic and electroencephalography (EEG) differences among them. SUBJECTS AND METHODS: The subjects were 26 children with MS, including benign myoclonic epilepsy in infants (BME) in 10, severe myoclonic epilepsy in infants (SME) in 6, idiopathic epilepsy with myoclonic-astatic seizures (IEMAS) in 4, and juvenile myoclonic epilepsy (JME) in 6. We reviewed the video-polygraphs of MS, including the predominant area of muscle involvement (neck, trunk, and proximal or distal upper extremities), postural changes including astatic falling, and mode of appearance. We also analyzed the frequency of a corresponding generalized spike-and-wave complex (GSW) and the duration of myoclonic electromyography (EMG) activity. RESULTS: A total of 550 MS were documented in the 26 cases. MS manifested with proximal predominance/forward flexion/single occurrence in BME, proximal predominance/forward astatic flexion/single occurrence in IEMAS, proximal predominance/extension/succession in SME, and distal predominance/extension/succession in JME. The median frequency of GSW was 1.5, 1.3, 3.2, and 3.1 Hz, respectively, and the median duration of the myoclonic EMG activity was 387, 587, 81, and 65 ms, respectively. CONCLUSION: MS in the four different epileptic syndromes show significant semiologic and EEG differences, as well as similarities. Although our study has the limitations of the small number of patients and retrospective methodology, these results should be considered in the classification and differential diagnosis of myoclonic epileptic syndromes.

[Clinical and EEG studies of symptomatic focal epilepsy in 7 patients with colpocephaly].

The clinical observations of seven patients with epileptic seizures and colpocephaly were summarized. The ages at the time of onset of the seizures were usually under 1 year, and the frequency of seizures in the late-onset cases was lower than that in the early-onset cases. The seizures were characterized by vomiting, eye deviation, versive seizures, and focal motor seizures. Interictal electroencephalograms showed either unilateral or synchronous bilateral spikes (and wave) or slowing of the basic activity in the occipital area. The basic activity slowed down in all of the cases. Epileptic seizures accompanied with colpocephaly may derive from epileptic foci in the occipital and posterior temporal region, which is structurally abnormal. Ongoing convulsions ceased after the intravenous administration of diazepam. In addition, the oral antiepileptics clobazam and clorazepate proved to be effective for the treatment of refractory cases.

[Clinical study on temporal lobe epilepsy in childhood caused by temporal lobe space-occupying lesions].

We studied the clinicoelectrical and neuroimaging features of 11 patients with symptomatic temporal lobe epilepsy (TLE) caused by temporal lobe space occupying lesions (SOLs), and compared its characteristics with those of 19 mesial TLE (MTLE) patients. Brain MRI demonstrated SOLs in the mesiotemporal lobe in 9, and laterotemporal lobe in the remaining 2 patients. Ten of the 11 patients successfully underwent surgery, which revealed tumors in 7 and focal cortical dysplasia in 3 patients. Comparisons of the clinical features between those with SOTLE and MTLE showed that both conditions shared the same clinical seizure manifestations such as gastric uprising sensation or ictal fear and a favorable response to surgery. However, the patients with SOTLE had fewer febrile convulsion, and more frequent seizure recurrences as well as TLE EEG discharges and associations of the monophasic clinical course than those with MTLE. In addition, the MRI findings were characterized by unilateral hippocampal atrophy in MTLE and expanding or SOLs in the SOTLE group. Children with complex partial seizures of suspected temporal lobe origin should undergo extensive neuroimaging evaluation.

Three patients with severe bilateral frontoparietal polymicrogyria.

The bilateral frontoparietal polymicrogyria syndrome is characterized anatomically by predominantly frontoparietal diffuse polymicrogyria and clinically by generalized tonic-clonic seizures and mental retardation developing in early childhood. Despite the diffuse nature of the cortical involvement, patients do gain the ability to speak and to walk. In addition, epilepsy can be relatively well controlled with antiepileptic drugs. In three cases of bilateral frontoparietal polymicrogyria, the patients demonstrated consistently similar clinical and neuroimaging characteristics, with more severe structural and developmental abnormalities than those reported previously. The designation proposed here recognizes such cases as a severe form of bilateral frontoparietal polymicrogyria. An ethnic difference or a causal gene other than GPR56 might be responsible for the difference in severity between the classical and the more severe forms of bilateral frontoparietal polymicrogyria.

TRH therapy in a patient with juvenile Alexander disease.

Alexander disease is a rare disorder of the central nervous system caused by a de novo mutation in the glial fibrillary acidic protein (GFAP) gene. Unlike the much more common infantile form, the juvenile form is slowly progressive with bulbar, pyramidal and cerebellar signs. Herein, we report a 9-year old Japanese girl suffering from frequent vomiting, slurred speech and truncal ataxia. Juvenile Alexander disease was diagnosed by genetic analysis, which detected a novel GFAP mutation, D360V. We also describe our clinical success in treating this patient with thyrotropin releasing hormone (TRH).

Extremely low-dose ACTH step-up protocol for West syndrome: maximum therapeutic effect with minimal side effects.

We studied the effectiveness of our new ACTH treatment strategy for West syndrome (WS), which was based on the results of our previous extremely low-dose ACTH study. The subjects were 31 infants with WS (cryptogenic WS in nine; symptomatic WS in 22). Synthetic ACTH-Z in a dose of 0.005 mg (= 0.2 IU)/kg/day was injected once every morning for at least 2 weeks, up to a maximum of 3 weeks. When this first treatment course achieved full seizure and EEG control, ACTH was tapered to zero over the subsequent 1 or 2 weeks. In the absence of a documented response, the dosage was increased to 0.025 mg (= 1.0 IU)/kg/day for the next 2 weeks (second treatment course). We analyzed the short-term as well as long-term effects, and the incidence of side effects. The first treatment course successfully controlled both spasms and hypsarrhythmia in 17 patients (55%), only spasms in one, and hypsarrhythmia in two. The second treatment course was then introduced in eight of the remaining 14 patients, providing complete suppression of WS in an additional two patients. Regarding the long-term effects, 13 patients (48%), with excellent short-term results and a longer than 1-year follow-up, remained seizure-free. Side effects of a mild degree were seen in 13 patients during ACTH treatment. Our new ACTH step-up method brought 61 and 48% of the patients into short-term and long-term remission, respectively, without significant side effects. The dose of ACTH required to control WS appears to be unexpectedly smaller than the dose we previously used.

[Clinical and electroencephalogram study of 5 children with hypothalamic hamartoma].

We retrospectively studied 5 children with hypothalamic hamartoma (HH) to elucidate the clinical, neuroimaging and electroencephalogram (EEG) characteristics of this disorder. In all cases, high resolution MRI scans demonstrated an intrahypothalamic mass protruding into the 3rd ventricle. An initial symptom was epileptic attack in 4 cases and precocious puberty in the remaining one. Gelastic seizures developed in 4 of 5 patients at ranging from 2 days to 11 years of age. The ictal EEGs during the gelastic seizures showed diffuse attenuation of background activity, followed by rhythmic slow discharges either diffusely or in the central area. Gamma-knife radiosurgery was performed on 2 cases whose seizures were resistant to available antiepileptic drugs. One of the 2 patients was responded significantly to this treatment, showing the disappearance of combined attacks and a marked reduction of the generalized spike-waves discharges. A more aggressive therapy, including gamma-knife radiosurgery and surgical treatment, should be considered for patients whose seizures are resistant to the medical treatment and causing deterioration of intelligence and behavioral problem.

Zonisamide for West syndrome: a comparison of clinical responses among different titration rate.

We administered zonisamide (ZNS) to patients with West syndrome in different titration protocols and compared their short-term therapeutic effects. We designed three protocols to raise the serum ZNS concentration (SZC): (1) increase the dose in three steps, from 3 to 10 mg/kg every 3 days, (2) increase the dose from 5 to 10 mg/kg over 3-7 days, and (3) start with 10 mg/kg and maintain this dosage for 2 weeks. The subjects were 23 infants with West syndrome, 8 of whom comprised the 1st group, 5 the 2nd group, and the remaining 10, the 3rd group. As a result, excellent and good effects were obtained in a total of seven patients (30.4%) and one patient, respectively (1/8 in the 1st step-up group, 3/5 in the 2nd step-up group, and 4/10 in the 3rd group). The maximum SZC was higher in the excellent and good effect groups (n=8; 32.0+/-8.0 microg/ml) than in the ineffective group (n=15; 22.4+/-8.2 microg/ml) (P<0.05). The period of time required for cessation of spasms appeared shorter in the 3rd group (n=4; mean=5.7 days) than in the 1st and 2nd groups (n=4; mean=10.3 days). There were few side effects except for transient hyperthermia and gastrointestinal symptoms. Our new protocol of starting with 10 mg/kg of ZNS can be introduced safely and make a therapeutic judgment feasible within 2 weeks.

Clinical presentation, EEG studies, and novel mutations in two cases of GLUT1 deficiency syndrome in Japan.

We report the first two Japanese children diagnosed with glucose transporter type 1 (GLUT1) deficiency syndrome. Both boys had been treated under the initial diagnosis of epilepsy and were reinvestigated for previously unexplainable hypoglycorrhachia. Myoclonic seizures developed at 4 months of age in Patient #1 (7 years old), and at 2 months of age in Patient #2 (11 years old), followed by cerebellar ataxia, spastic diplegia, and mental retardation. Both patients had hypoglycorrhachia, and the symptoms were more severe in the latter. CSF and serum glucose levels determined simultaneously showed a CSF/serum glucose ratio of below 0.4 in both patients. In mildly affected Patient #1, the postprandial waking EEG showed improvement in the background activity, as compared to that recorded after overnight fasting, while no significant changes were observed in severely affected Patient #2. In both patients, the functional GLUT1 defect was confirmed by 3-O-methyl-D-glucose uptake into erythrocytes. Molecular analyses identified heterozygous novel mutations in both patients, within exons 6 and 2 of the GLUT1 gene, respectively. The ketogenic diet was refused in Patient #1, but started in Patient #2 with significant clinical benefit. Fasting CSF analysis and pre-/postprandial EEG changes in children with epileptic seizures and unexplainable neurological deterioration help in diagnosing this potentially treatable disorder.

Effect of ACTH therapy for epileptic spasms without hypsarrhythmia.

PURPOSE: We analyzed the short- and long-term effects of adrenocorticotropic hormone (ACTH) therapy for patients with epileptic spasms (ESs) who did not meet the criteria of West syndrome (WS). METHODS: The subjects were 30 patients, including 13 boys and 17 girls, who had received ACTH therapy between 1970 and 2003. We excluded patients with WS, but included those with a history of WS who no longer showed hypsarrhythmia at the period of ACTH therapy. The age at onset of ESs and at ACTH therapy ranged from 2 to 82 months with a median of 18 months, and from 11 to 86 months with a median of 29 months, respectively. RESULTS: Excellent and poor responses were obtained in 19 (63%) and 11 (37%) patients, respectively, as a short-term effect. Although the patients could be subclassified into five subgroups according to the previous reports, no difference was seen in short- term response to ACTH. Among 17 of the 19 patients with excellent short-term outcomes and a follow-up of >1 year after the ACTH therapy, eight patients have continued to be seizure free (29%; excellent long-term effect), whereas the remaining nine patients had a recurrence of seizures (complex partial seizures, four; generalized tonic seizures, three; ESs, two) at 9 months to 198 months (median, 49 months) after ACTH therapy. In addition, nine of the 17 patients demonstrated a localized frontal EEG focus after the ACTH therapy, although most of these had previously shown diffuse epileptic EEG abnormality. CONCLUSIONS: ACTH therapy is worth trying for patients with resistant ESs, even without features of WS. However, the long-term effect is uncertain because recurrences of various types of seizures, including focal, were frequently observed.