Voltage-gated sodium channel epilepsies in a tertiary care center: Phenotypic spectrum with correlation to predicted functional effects.

BACKGROUND: Variants in sodium channel genes (SCN) are strongly associated with epilepsy phenotypes. Our aim in this study to evaluate the genotype and phenotype correlation of patients with SCN variants in our tertiary care center. METHODS: In this retrospective study, patients with SCN variants and epilepsy who were followed up at our clinic between 2018 and 2022 were evaluated. Our study discussed the demographics of the patients, the seizure types, the age of seizure onset, the SCN variants, the domains and the functions of the variants, the magnetic resonance imaging findings, the motor, cognitive, and psychiatric comorbidities, and the response to anti-seizure medication. Genetic testing was conducted using a next-generation sequencing gene panel (epilepsy panel) or a whole-exome sequencing. For evaluating variant function, we used a prediction tool (https://funnc.shinyapps.io/shinyappweb/ site). To assess protein domains, we used the PER viewer (http://per.broadinstitute.org/). RESULTS: Twenty-three patients with SCN variants and epilepsy have been identified. Sixteen patients had variants in the SCN1A, six patients had variants in the SCN2A, and one patient had a variant in the SCN3A. Two novel SCN1A variants and two novel SCN2A variants were identified. The analysis revealed 14/23 missense, 6/23 nonsense, 2/23 frameshift, and 1/23 splice site variants in the SCN. There are seven variants predicted to be gain-of-function and 13 predicted to be loss-of-function. Among 23 patients; 11 had Dravet Syndrome, 6 had early infantile developmental and epileptic encephalopathy, three had genetic epilepsy with febrile seizures plus spectrum disorder, one had self-limited familial neonatal-infantile epilepsy, one had self-limited infantile epilepsy and one had infantile childhood development epileptic encephalopathy. CONCLUSION: Our cohort consists of mainly SCN1 variants, most of them were predicted to be loss of function. Dravet syndrome was the most common phenotype. The prediction tool used in our study demonstrated overall compatibility with clinical findings. Due to the diverse clinical manifestations of variant functions, it may assist in guiding medication selection and predicting outcomes. We believe that such a tool will help the clinician in both prognosis prediction and solving therapeutic challenges in this group where refractory seizures are common.

A Retrospective Review of 18 Patients With Childhood-Onset Hereditary Spastic Paraplegia, Nine With Novel Variants.

BACKGROUND: Hereditary spastic paraplegias (HSPs) are a group of genetically heterogeneous neurodegenerative disorders. Our objective was to determine the clinical and molecular characteristics of patients with genetically confirmed childhood-onset HSPs and to expand the genetic spectrum for some rare subtypes of HSP. METHODS: We reviewed the charts of subjects with genetically confirmed childhood-onset HSP. The age at the disease onset was defined as the point at which the delayed motor milestones were observed. Delayed motor milestones were defined as being unable to hold the head up by four months, sitting unassisted by nine months, and walking independently by 17 months. If there were no delayed motor milestones, age at disease onset was determined by leg stiffness, frequent falls, or unsteady gait. Genetic testing was performed based on delayed motor milestones, progressive leg spasticity, and gait difficulty. The variant classification was determined based on the American College of Medical Genetics standard guidelines for variant interpretation. Variants of uncertain significance (VUS) were considered disease-associated when clinical findings were consistent with the previously described disease phenotypes for pathogenic variants. In addition, in the absence of another pathogenic, likely pathogenic, or VUS variant that could explain the phenotype of our cases, we concluded that the disease is associated with VUS in the HSP-causing gene. Segregation analysis was also performed on the parents of some patients to demonstrate the inheritance model. RESULTS: There were a total of 18 patients from 17 families. The median age of symptom onset was 18 months (2 to 84 months). The mean delay between symptom onset and genetic diagnosis was 5.8 years (5 months to 17 years). All patients had gait difficulty caused by progressive leg spasticity and weakness. Independent walking was not achieved at 17 months for 67% of patients (n = 12). In our cohort, there were two subjects each with SPG11, SPG46, and SPG 50 followed by single subject each with SPG3A, SPG4, SPG7, SPG8, SPG30, SPG35, SPG43, SPG44, SPG57, SPG62, infantile-onset ascending spastic paralysis (IAHSP), and spastic paraplegia and psychomotor retardation with or without seizures (SPPRS). Eight novel variants in nine patients were described. Two affected siblings had a novel variant in the GBA2 gene (SPG46), and one subject each had a novel variant in WASHC5 (SPG8), SPG11 (SPG11), KIF1A (SPG30), GJC2 (SPG44), ERLIN1 (SPG62), ALS2 (IAHSP), and HACE1 (SPPRS). Among the novel variants, the variant in the SPG11 was pathogenic and the variants in the KIF1A, GJC2, and HACE1 were likely pathogenic. The variants in the GBA2, ALS2, ERLIN1, and WASHC5 were classified as VUS. CONCLUSIONS: There was a significant delay between symptom onset and genetic diagnosis of HSP. An early diagnosis may be possible by examining patients with delayed motor milestones, progressive spasticity, gait difficulties, and neuromuscular weakness in the context of HSP. Eight novel variants in nine patients were described, clinically similar to the previously described disease phenotype associated with pathogenic variants. This study contributes to expanding the genetic spectrum of some rare subtypes of HSP.

Association of epilepsy with neuroimaging patterns in children with cerebral palsy.

OBJECTIVES: In this study, we examined whether epilepsy and drug-resistant epilepsy are associated with neuroimaging findings in children with cerebral palsy (CP). METHODS: Magnetic resonance imaging classification system (MRICS) proposed by Surveillance of Cerebral Palsy in Europe (SCPE) was used for classification of different MRI patterns in patients with cerebral palsy. We reviewed the brain MRI scans and medical records of children with CP who were followed-up in our clinic between 2019 and 2023. Patients were divided into three categories: CP without epilepsy, CP with controlled epilepsy and CP with DRE. MRI patterns were grouped as maldevelopments, predominant white matter injury, predominant gray matter injury, miscellaneous (delayed myelination, cerebral atrophy, cerebellar atrophy, brainstem lesions and calcifications, lesions that were not classified under any other group) and normal according to MRICS of the SCPE. RESULTS: There were 325 CP patients. The most common MRI patterns were predominant white matter injury (47.6%) and gray matter injury (23.8%). There was a 1.5-fold reduction in the risk of epilepsy in patients with predominant white matter injury (OR = 1.54, 95% CI 1.23-1.94). In contrast, children in the miscellaneous group had significantly higher risks of epilepsy (p < 0.001), and we were able to determine that miscellaneous findings increased the risk by 1.8 times (OR = 1.77, 95% CI 1.47-2.12). CONCLUSION: In conclusion, more than half of the children with CP had epilepsy, 40.7% of whom had DRE. On MRI, miscellaneous findings may indicate a poor prognosis for epilepsy, while predominant white matter injury may indicate a good outcome. Children with CP, especially those with miscellaneous findings on MRI, should be closely monitored for epilepsy development.

Chronic inflammatory demyelinating neuropathy after etanercept therapy in the course of juvenile idiopathic arthritis.

BACKGROUND: Chronic inflammatory demyelinating neuropathy has been reported after the use of tumor necrosis factor inhibitors. The mechanisms of nerve injury caused by tumor necrosis factor inhibitors are not yet well understood. CASE: In this paper, we report a 12 year and nine month old girl who developed chronic inflammatory demyelinating neuropathy in the course of juvenile idiopathic arthritis after etanercept withdrawal. She became non-ambulant with four-limb involvement. She received intravenous immunoglobulins, steroids, and plasma exchange, but had a limited response. Finally, rituximab was given and a slow, but progressive clinical improvement was seen. She was ambulant four months after rituximab treatment. We considered chronic inflammatory demyelinating neuropathy as a probable adverse effect of etanercept. CONCLUSIONS: Tumor necrosis factor inhibitors could elicit the demyelinating process, and chronic inflammatory demyelinating neuropathy might persist despite treatment discontinuation. First-line immunotherapy may be inefficient as in our case, and aggressive treatment may be necessary.

Neurodevelopmental Outcome in Patients with Typical Imaging Features of Injury as a Result of Neonatal Hypoglycemia.

Introduction: Previous reports described a pattern of hypoglycemia-induced damage predominantly affecting the parieto-occipital regions. The long-term neurological sequelae of severe neonatal hypoglycemic encephalopathy include developmental delay, poor head growth, learning or behavioral difficulties, visual impairment, and epilepsy. This study reports neurodevelopmental outcome of children with neonatal hypoglycemia-associated parieto-occipital brain injury who were evaluated in our pediatric neurology outpatient clinic for different neurological complaints. Methods: We retrospectively reviewed patients who were followed at Kocaeli University Hospital, Pediatric Neurology Department between 2007 and 2015. Patients (n=42) with predominately parieto-occipital lesions on magnetic resonance imaging (MRI) with the typical pattern of neonatal hypoglycemia were evaluated. Patients with documented hypoglycemia (n=21) were included in this study. Patients (n=9) with recurrent episodes of hypoglycemia longer than 12 hours were evaluated as prolonged hypoglycemia. Results: Eleven patients (52.4%) experienced seizures in the neonatal period. Eighteen patients (85.7%) developed epilepsy during the follow-up. Refractory seizures were observed in 8 patients (38.1%). Nine patients (42.9%) manifested microcephaly, seven patients (33.3%) manifested cerebral palsy. Parieto-occipital involvement and the spasticity rate were statistically high in patients with prolonged hypoglycemia (p<0.01). Two patients had autistic features and four patients (19%) had attention deficit hyperactivity disorder. VEP studies could be performed in 18 of 21 patients. All patients had abnormal VEP results. Conclusion: We are of the opinion that most patients of neonatal hypoglycemia are not always documented. Patients under risk and patients with symptoms of hypoglycemia should be vigorously screened and treated to prevent neurologic impairments including cerebral palsy, epilepsy and visual disturbance.

Proteomic Analysis of m.8296A>G Variation in the Mitochondrial tRNA Lys Gene.

Variation in the mitochondrial tRNA Lys gene at position 8296 was previously found to be associated with maternally inherited diabetes mellitus and deafness, hypertrophic cardiomyopathy, myoclonic epilepsy with ragged-red fibers and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The pathogenicity of the m.8296A>G variation is unclear. In this study, we aimed to analyze the mitochondrial proteome in a patient with m.8296A>G variation to elucidate the effects of this mutation at the protein level. Whole-exome sequencing and mitochondrial genome analysis were performed in a patient with sensorineural hearing impairment, cognitive impairment, leukodystrophy, migraine-like headaches, and gastrointestinal dysmotility. Mitochondrial genome analysis identified a homoplasmic m.8296A>G variation in the mitochondrial tRNA Lys gene in the proband and unaffected mother. Global mitochondrial proteome analysis was carried out in the muscle mitochondria of the index patient and a control subject. Comparative muscle mitochondrial proteome analysis revealed a total of 13 nuclear-encoded mitochondrial proteins differently expressed with respect to the control. Ten of the 13 proteins were downregulated. Most of the proteins were involved in ATP synthesis and Krebs cycle and have strong interactions with each other. We considered the m.8296A>G variation to be pathogenic with variable penetrance for our patient's phenotype, and this variation led to different expressions of nuclear-encoded proteins involved in energy metabolism.

Primary adrenal insufficiency in a patient with biallelic QRSL1 mutations.

Background: Biallelic QRSL1 mutations cause mitochondrial 'combined oxidative phosphorylation deficiency-40' (COXPD40). COXPD40 has been reported to be invariably lethal in infancy. Adrenal insufficiency was weakly reported and investigated among seven previously reported patients with COXPD40. Objective: We report the clinical, biochemical, molecular, and functional characteristics of a patient with adrenal insufficiency due to COXPD40. Methods: The medical history and adrenal function tests were examined. Genetic analysis was performed using whole-exome sequencing. Mitochondrial function was tested using mitochondrial membrane potential (MMP) and superoxide dismutase (SOD) enzyme assays. Results: An 8-year-old boy was investigated for adrenal insufficiency. He also had mild developmental delay, sensorineural hearing loss, hypertrophic cardiomyopathy, nephrocalcinosis, elevated parathyroid hormone and creatine kinase, and lactic acidosis. Biallelic novel QRSL1 variants (c.300T>A;Y100* and c.610G>A;G204R) were identified. Oxidative damage in mitochondria was shown by reduced MMP and SOD assays in the patient compared to controls (P < 0.0001). Adrenal function tests revealed a 'primary adrenal insufficiency other than congenital adrenal hyperplasia' (non-CAH PAI) with an isolated glucocorticoid deficiency. In the 8-year follow-up, having the longest survival of reported COXPD40 patients, he had preserved mineralocorticoid functions and gonadal steroidogenesis. Conclusion: Biallelic QRSL1 mutations can cause non-CAH PAI. Adrenal functions should be monitored in mitochondrial disorders to improve clinical outcomes.

BEND4 as a Candidate Gene for an Infection-Induced Acute Encephalopathy Characterized by a Cyst and Calcification of the Pons and Cerebellar Atrophy.

Three siblings born to Turkish parents from the same village had normal brain development until acute neurological deterioration between 12 months and 8 years of age. Consequent loss of all acquired motor, social, and language functions following infections was associated with a pontine cyst, calcification, and cerebellar atrophy. Exome sequencing revealed a homozygous c.1297G>A (p.Gly433Ser) alteration in BEND4, which was predicted to be deleterious in in silico analysis tools and segregated in multiple affected individuals in the family. BEND4 has not been associated with any existing disease. Immunofluorescence microscopy analysis of wild-type and mutant BEND4 expressing Vero cells showed nuclear and cytoplasmic localization. Wild-type BEND4 displayed a network-like distribution, whereas mutant BEND4 showed a juxtanuclear distribution pattern. Differential proteome analysis of Vero cells expressing BEND4 revealed that mutant BEND4 expression caused selective increase in reticulocalbin-1 and endoplasmic reticulum resident protein-29. Both proteins are associated with the endoplasmic reticulum and are primarily involved in protein processing and folding pathways. Any defect or stress in protein folding creates stress on cells and may cause chronic damage. This is the first study showing that pathogenic BEND4 variants may lead to an infection-induced acute necrotizing encephalopathy as demonstrated in characteristic neuroimaging findings.

Cytotoxic lesions of the corpus callosum in children: Etiology, clinical and radiological features, and prognosis.

OBJECTIVES: Cytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with entities like infection manifested by restricted diffusion on diffusion-weighted cranial magnetic resonance imaging. Our objectives are to evaluate the clinic-radiological spectrum of pediatric patients with cytotoxic lesions of the corpus callosum (CC). METHODS: Children (0-18 years) admitted between February 2017 and May 2020 with splenial lesions showing diffusion restriction on MRI, either isolated or within involvement of other parts of the brain, were included retrospectively. The primary lesions of the CC (e.g. acute disseminated encephalomyelitis, acute ischemic infarction, and glioblastoma multiforme) were excluded. CLOCCs were divided into infection-associated, metabolic disorder-associated, and trauma-associated lesions, as well as CLOCCs involving other entities. Data were collected from the medical databases. RESULTS: Forty-one patients were determined to have CLOCCs. Twenty-five (61%) were infection-associated, nine (22%) were trauma-associated, and three (7%) were metabolic disorder-associated cases, including 2 inherited disorders of metabolism. There were four (10%) patients with other entities, three with epilepsy, and one had an apparent life-threatening event. Six patients had a known etiology among the infection-associated group; one had multisystem inflammatory syndrome caused by COVID-19 and one had been infected by COVID-19 without any complications. All the infection-associated patients with isolated splenial lesions recovered totally, although six patients required intensive care hospitalization. Four trauma-associated patients had sequela lesions. CONCLUSIONS: CLOCCs are associated with a spectrum of diseases, including the new coronavirus, COVID-19 infection. Infection-associated CLOCCs has the best prognosis, although severe cases may occur. Sequelae are possible based on the etiology.

Diagnostic yield of muscle biopsy in infants: Retrospective analysis of clinical and histopathologic findings.

The aim was to define the clinical and histopathologic findings of infants who underwent muscle biopsy and identify the diagnostic yield of muscle biopsy in this cohort. Infants who underwent muscle biopsy from January 2010 to March 2017 at a tertiary hospital were included in the study (N = 87; 64 boys (73.6%), 23 girls (26.4%); age range 0 - 2 years; mean age 9.73 ± 7.04 months). Clinical and histopathologic data were obtained from medical records. Developmental delay (64.4%) and hypotonia (59.8%) were the most frequent clinical findings, and mitochondrial disease (61%) was the most frequent clinical diagnosis, followed by muscular dystrophy (15.9%) and congenital myopathy (11.5%). Creatine kinase level was normal in 65.9% and > 1,000 U/L in 17.1%. Specific pathologic findings were identified from 38 biopsies (43.7%). The most frequent pathologic findings were features compatible with mitochondrial/metabolic myopathy (14 patients, 16.1%) and muscular dystrophy (12 patients, 13.8%). Myopathic changes were present in 7 biopsy samples (8.0%) and neurogenic changes in 5 (5.7%). The clinical and pathologic diagnoses were compatible in 24 patients (63.2%). The diagnostic yield of muscle biopsy remains significant, especially in this age group. Mitochondrial disease is a major diagnostic challenge, and muscle biopsy helps to support the clinical diagnosis and guide further studies.

Acute flaccid myelitis outbreak through 2016-2018: A multicenter experience from Turkey.

AIM: We aim to describe the demographic characteristics, etiology, neurophysiology, imaging findings, treatment, prognosis, and prognostic factors of acute flaccid myelitis. METHODS: The clinical data, laboratory test and, magnetic resonance imaging (MRI) results of pediatric patients diagnosed with acute flaccid myelitis according to the Centers for Disease Control criteria between August 1, 2016, and December 31, 2018, from 13 centers in Turkey were reviewed. RESULTS: Of the 34 cases identified, 31 were confirmed (91.2%). Eighteen patients (55.9%) were boys. The median patient age was 4 years (interquartile range 2.5-6.9 years). Most of the patients were admitted in 2018 (n = 27). A preceding history of a febrile illness was reported in all patients, with a median of 4 days (interquartile range 3-7 days) before symptom onset. Thirty-one patients had T2 hyperintensity on spinal MRI, and 18 patients had cerebrospinal fluid pleocytosis. The most common infectious agents were entero/rhinoviruses (n = 5) in respiratory specimens. All patients except one received immunotherapy either alone or in combination. Among 27 patients with follow-up data 24 had persistent weakness. Involvement of four limbs together with an abnormal brain MRI at onset were associated with a poor prognosis. CONCLUSION: The number of patients with acute flaccid myelitis increased since 2012, spiking with every 2-year interval, largely in the pediatric population. The median age decreases with every outbreak. Clinicians should be aware of the clinical picture for early collection of specimens and early start of rehabilitation programs. Further studies are needed to better characterize the etiology, pathogenesis, risk factors, and treatment of this rare condition.

Vanishing white matter disease with different faces.

PURPOSE: The goal of this study was to better understand vanishing white matter (VWM) disease, which is one of the most common hereditary white matter disorders, and its relationship to radiologic features, genetic analyses, and clinical findings. METHODS: We performed a study on 11 patients to describe the clinical and neuroimaging features of VWM. Patients were grouped into "infantile," "early childhood," and "juvenile" based on their onset age. EIF2B1-5 genes encoding five subunits of eukaryotic translation initiation factor 2B (eIF2B) were analyzed in all patients with clinically suspected VWM disease. RESULTS: In brain magnetic resonance imaging (MRI), all patients showed white matter abnormalities with various degrees. The initial clinical presentation in five of patients was ataxia, with severe refractory epilepsy in three patients. In children with infantile-onset VWM, a rapid deterioration of motor function was detected, and the frequency of epilepsy was higher. Two patients showed manifestations of end-stage VWM disease, and one of them had chronic subdural hematoma. One of our patients and his father were diagnosed with Brugada syndrome. Sequencing of the exons and exon-intron boundaries of the EIF2B1-5 genes revealed mutations in the genes EIF2B5 (5 cases), EIF2B3 (3 cases), and EIF2B4 (2 cases). We also found a novel mutation in one patient: c.323_325delGAA in the EIF2B1 gene. CONCLUSIONS: In this study, in addition to classical clinical and radiological findings, we wanted to emphasize that we may be confronted with refractory epilepsy (early infancy), cardiac problems, and intracranial complications that may occur in advanced stages.

Acute ophthalmoparesis and persistent mydriasis: expanding the clinical spectrum of anti-GQ1b positive cranial neuropathy in a 5.5-year-old girl.

Sakarya Günes A, Maras Genç H, Uyur Yalçin E, Yilmaz V, Saruhan Direskeneli G, Kara B. Acute ophthalmoparesis and persistent mydriasis: expanding the clinical spectrum of anti-GQ1b positive cranial neuropathy in a 5.5-year-old girl. Turk J Pediatr 2019; 61: 794-797. Acute ophthalmoparesis without ataxia (AO) is an atypical form of Miller- Fisher syndrome (MFS) and is rare in children. Anti-GQ1b antibodies can be detected in patients with AO, as in MFS. A 5.5-year-old girl had total ophthalmoparesis, blurred vision, ptosis, diplopia and mydriasis non-reactive to light or near stimuli with preserved consciousness and deep tendon reflexes. She had no ataxia. Cerebrospinal fluid (CSF) examination and cranial MRI were normal. Serum antiGQ1b antibodies were positive. She was diagnosed with AO and intravenous Immunoglobulin (IVIG) was ordered, 400 mg/ kg/day, for 5 days. Ophthalmoparesis and blurred vision improved in a few weeks. At the end of the first year, mydriasis still persisted, but improved and became responsive to near stimuli. Pupillary involvement may be seen in approximately 50% of MFS patients, and improvement in a few weeks or months has been reported in adults. Our case shows the expanding clinical spectrum of anti-GQ1b positive cranial neuropathy as early-onset AO and prolonged mydriasis more than one year.

Risk factors and motor outcome of paediatric stroke patients.

BACKGROUND: Childhood stroke causes significant morbidity and mortality. In this study, we aimed to define the presenting findings, causes, risk factors and motor outcomes of our patients. METHODS: We retrospectively analysed patients aged from 1 month to 18 years who were diagnosed as having the first onset of stroke between January 2006 and December 2015. Presenting features, causes, risk factors, recurrence rate and motor outcomes were recorded. Motor outcome was evaluated by the gross motor function classification system. RESULTS: Forty-seven children were included in the study. Thirty-eight (78.7%) children had an arterial stroke, 9 (19.1%) had a venous stroke. The median age at the time of presentation was 60 months (3-214). Thirty-two patients (68%) presented with a focal neurological sign and 9 presented with seizure (19.1%). Patients who had a venous stroke presented with more diffuse neurological symptoms than those who had an arterial stroke. At least one risk factor for stroke was identified in 74.5% of the patients; the most common causative factor was prothrombotic state seen in 16 patients (33.5%). Stroke recurred in 5 patients (10.6%); coexistence of multiple factors was a risk factor for recurrence. Presenting with seizure was not a facilitator for epilepsy. Thirty-two (68%) patients had a favourable motor outcome. Younger age (24 months versus 114 months) and presenting with focal neurological signs were related to non-favourable motor outcome. CONCLUSION: Our cohort demonstrates that most of the children had a risk factor for stroke and have had favourable motor outcome. However, younger age and presenting with focal seizures are related to non-favourable motor outcome.

Mild encephalitis/encephalopathy with a reversible splenial lesion in children.

PURPOSE: We aimed to present clinical and radiologic characteristics of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) in children. METHODS: Eight children (5 boys and 3 girls; median age, 5.9 years; age range, 8 months to 14.1 years) diagnosed with MERS between September 2015 and June 2017 were included in the study. We reviewed the patient's data, including demographic characteristics, prodromal and neurologic symptoms, neurologic examination, magnetic resonance imaging and electroencephalography findings, laboratory findings, treatment, and prognosis. RESULTS: Prodromal symptoms were nausea and vomiting (n=6), diarrhea (n=6), and fever (n=3). Initial neurologic symptoms were seizures (n=4), delirious behavior (n=1), drowsiness (n=1), ataxia (n=1), transient blindness (n=2), abnormal speech (n=2), and headache (n=1). Two patients had a suspected infective agent: urinary tract infection caused by Escherichia coli and gastroenteritis caused by rotavirus. Seven patients had type I lesions, comprising characteristic symmetric ovoid (n=6) and band-shaped (n=1) T2-weighted hyperintense lesions at the spenium of corpus callosum, and one patient had type II lesion with additional symmetric posterior periventricular lesions. The lesions were isointense to mildly hypointense on T1-weighted imaging and did not show enhancement. All lesions displayed restricted diffusion. In all patients, neurologic symptoms completely normalized < 48 hours from the onset of symptoms without any sequelae. CONCLUSION: MERS has characteristic imaging features and favorable outcome.

Long-term clinical and radiologic follow-up of Schilder's disease.

BACKGROUND: Schilder's disease is a rare, subacute, or chronic demyelinating disorder that mainly affects children and generally shows a monophasic course. CASE: Here, we present three boys diagnosed with Schilder's disease, age at onset 10-14 years, and followed up for 4-8 years. All of them presented with headache, two with encephalopathy and vomiting, and one with diplopia and vertigo. Cranial magnetic resonance imaging (MRI) showed two large demyelinating lesions, asymmetric in two patients and symmetric in the other. They were treated with steroid therapy. There were no radiologic relapses after discontinuation of corticosteroid therapy in all patients, but clinical attack without objective clinical findings was observed in one patient. Mild memory deficits and decline in school performance were the only neurologic sequelae in two patients. Cranial MRI findings showed significant shrinkage, but persistent T2-weighted hyperintensity of white matter lesions and loss of ring contrast enhancement at the end of the steroid therapy. There were no differences between the radiologic findings at the end of the steroid therapy and subsequent follow-ups. CONCLUSION: Although Schilder's disease is considered to be a variant of MS, it behaves more like ADEM with its monophasic course, and low recurrence rates. Radiologic features include shrinkage of mass lesions after steroid therapy, but sequel lesions remain same at the subacute and chronic stage.

Severe neurodegenerative disease in brothers with homozygous mutation in POLR1A.

In two brothers born to consanguineous parents, we identified an unusual neurological disease that manifested with ataxia, psychomotor retardation, cerebellar and cerebral atrophy, and leukodystrophy. Via linkage analysis and exome sequencing, we identified homozygous c.2801C>T (p.(Ser934Leu)) in POLR1A (encoding RPA194, largest subunit of RNA polymerase I) and c.511C>T (p.(Arg171Trp)) in OSBPL11 (encoding oxysterol-binding protein-like protein 11). Although in silico analysis, histopathologic evidence and functional verification indicated that both variants were deleterious, segregation with the patient phenotype established that the POLR1A defect underlies the disease, as a clinically unaffected sister also was homozygous for the OSBPL11 variant. Decreased nucleolar RPA194 was observed in the skin fibroblasts of only the affected brothers, whereas intracellular cholesterol accumulation was observed in the skin biopsies of the patients and the sister homozygous for the OSBPL11 variant. Our findings provide the first report showing a complex leukodystrophy associated with POLR1A. Variants in three other RNA polymerase subunits, POLR1C, POLR3A and POLR3B, are known to cause recessive leukodystrophy similar to the disease afflicting the present family but with a later onset. Of those, POLR1C is also implicated in a mandibulofacial dysostosis syndrome without leukodystrophy as POLR1A is. This syndrome is absent in the family we present.

Pyruvate dehydrogenase-E1α deficiency presenting as recurrent acute proximal muscle weakness of upper and lower extremities in an 8-year-old boy.

The mitochondrial pyruvate dehydrogenase enzyme complex (PDHC) plays an important role in aerobic energy metabolism and acid-base equilibrium. PDHC contains of 5 enzymes, 3 catalytic (E1, E2, E3) and 2 regulatory, as well as 3 cofactors and an additional protein (E3-binding protein) encoded by nuclear genes. The clinical presentation of PDHC deficiency ranges from fatal neonatal lactic acidosis to chronic neurologic dysfunction without lactic acidosis. Paroxysmal neurologic problems such as intermittent ataxia, episodic weakness, exercise-induced dystonia and recurrent demyelination may also be seen although they are rare. Here, we present an 8-year-old boy complaining of acute proximal muscle weakness of upper and lower extremities with normal mental status. He had a history of Guillain-Barré-like syndrome at the age of 2 years. Electrophysiologic studies showed sensorial polyneuropathy findings in the first attack and sensorimotor axonal polyneuropathy findings in the last attack. The genetic analysis revealed a previously reported hemizygote novel mutation of the PDHA1 gene (p.A353T/c.1057G > A), which encodes the E1α subunit of PDHC. Thiamine was ordered (15 mg/kg/day), dietary carbohydrates were restricted and clinical findings improved in a few weeks. This rare phenotype of PDHC deficiency is discussed.