Young-Mock Lee

Safe and Effective Use of the Ketogenic Diet in Children with Epilepsy and Mitochondrial Respiratory Chain Complex Defects

Summary:  Purpose: To evaluate the clinical efficacy and safety of the ketogenic diet (KD) for patients with intractable childhood epilepsy and mitochondrial respiratory chain (RC) complex defects.

Neuroradiologic findings in children with mitochondrial disorder: correlation with mitochondrial respiratory chain defects

Mitochondrial disorders are a heterogeneous group of disorders affecting energy metabolism that can present at any age with a wide variety of clinical symptoms. We investigated brain magnetic resonance (MR) findings in 40 children with defects of the mitochondrial respiratory chain (MRC) complex and correlated them with the type of MRC defects. Enrolled were 40 children with MRC defects in biochemical enzyme assay of the muscle specimen. Twenty-one children were found to have classical syndromes of mitochondrial disorders and 19 children presented nonspecific mitochondrial encephalomyopathies. Their brain MR imaging findings were retrospectively reviewed and correlated with the biochemical defect in the MRC complex. Children with MRC defects showed various neuroradiologic features on brain MR imaging that resulted from a complex genetic background and a heterogeneous phenotype. Rapid progression of atrophy involving all structures of the brain with variable involvement of deep gray and white matter are the most frequent MR findings in children with MRC defects in both classical syndromes of mitochondrial disorder and nonspecific mitochondrial encephalomyopathies. The type of biochemical defect in the MRC complex enzyme did not correlate with brain MR findings in child patients.

Prognostic Factors of Status Epilepticus in Children

We retrospectively reviewed the medical records of 189 children who were admitted to the Pediatric Neurology Department at Yonsei University College of Medicine with status epilepticus (SE) between April, 1994 and April, 2003. The children were followed up for a mean duration of 17 months. We analyzed the clinical findings and the relationships between neurologic sequelae, recurrence, age of onset, presumptive causes, types of seizure, seizure duration and the presence of fever. Mean age at SE onset was 37 months. Incidences by seizure type classification were generalized convulsive SE in 73.5%, and non-convulsive SE in 26.5%. The incidences of presumptive causes of SE were idiopathic 40.7%, epilepsy 29.1%, remote 16.4% and acute symptomatic in 13.3%. Among all the patients, febrile episodes occurred in 35.4%, especially in patients under 3 year old, and 38.4% of these were associated with febrile illness regardless of presumptive cause. Neurologic sequelae occurred in 33% and the mortality rate was 3%. Neurologic sequelae were lower in patients that presented with an idiopathic etiology and higher in generalized convulsive SE patients. The recurrence of SE was higher in patients with a remote symptomatic epileptic etiology, and generalized convulsive SE showed higher rates of recurrence. Based on this retrospective study, the neurologic outcomes and recurrence of SE were found to be strongly associated with etiology and seizure type. Age, seizure duration and the presence of febrile illness were found to have no effect on outcome.

Seizure outcome of infantile spasms with focal cortical dysplasia.

PURPOSE This study sought to evaluate the seizure outcome of infantile spasms (IS) with focal cortical dysplasia (FCD). METHODS We retrospectively reviewed infantile spasms patients with FCD from 2004 to 2010. We investigated seizure outcome from antiepileptic drug (AED), ketogenic diet (KD), resective surgery, and analyzed the results according to individual imaging studies. RESULTS Among 404 patients of IS, FCD was confirmed in 51 patients. In retrospective review of brain MRI, only 21 patients (41.2%) were suspected of FCD before 1year of age, but 45 patients (88.2%) became confirmed to FCD by MRI after the age of 1year. Once the spasms were not controlled by 1 or 2 AEDs, the chance of becoming seizure free with additional third or more drugs was very low (2.3%). The seizure free rate was 33.3% (7/21) in patients treated with ketogenic diet, and 73.3% (22/30) in surgical patients, who were both intractable to AEDs. There were no significant differences in seizure free rate in both ketogenic diet and surgical patients, between MRI negative and positive patients prior to 1year of age. CONCLUSIONS KD and surgery should be considered in medically refractory IS with FCD.

Ophthalmological manifestations in patients with Leigh syndrome

Background To describe the ophthalmological manifestations in patients with childhood onset Leigh syndrome (LS) and investigate the correlation between genotypes and phenotypes in patients with LS. Methods Childhood onset LS was clinically and enzymatically confirmed in a total of 63 patients. Among them, 44 patients who underwent ophthalmologic consultation were included in this study. Patients with LS underwent genotyping for the whole genome of mitochondrial DNA and SURF1 mutations. The clinical demographic and ophthalmologic phenotypes were compared between the good prognosis group and the poor prognosis group. Results Strabismus (40.9%) was the most frequently observed ophthalmologic manifestation, followed by pigmentary retinopathy (22.5%), optic atrophy (22.5%), ptosis (15.9%), and nystagmus (13.6%). Thirteen patients were exotropes and five patients were esotropes. The mean exodeviation was 29.6±12.5 prism dioptres (PD) and the mean esodeviation was 24.0±8.9 PD. All patients with esotropia reported disease onset at <1 year old. Among 26 patients older than 4 years, eight (30.8%) patients had better than 0.4 in the best eye was noted. Eyelid ptosis was a main presenting sign in four patients (9.1%). Among these patients, two patients had m.13513G>A mutation in the MT-ND5 gene. Age at onset was 2.47±2.06 years in the good prognosis group and 0.92±0.98 years in the poor prognosis group (p=0.002). Serum lactate peak concentration was 3.23±1.36 mmol/L in the good prognosis group and 4.54±2.31 mmol/L in the poor prognosis group (p=0.051). Conclusions LS is a group of mitochondrial disorders with variable ophthalmologic manifestations, the most frequent being strabismus in this study. Ptosis could be an initial sign in patients with LS and these patients can be easily misdiagnosed as having juvenile myasthenia gravis.

An efficient liposomal gene delivery vehicle using Sendai F/HN proteins and protamine.

By means of a simple mixing procedure, we have constructed cationic Sendai virosomes consisting of fusogenic viral F/HN proteins and cationic lipids. Sendai virus F/HN proteins were purified by Triton X-100 treatment and sequential centrifugation, and then quantitatively added to cationic liposomes. The presence of HN proteins is essential for hemolytic activity of Sendai virus as well as efficient gene transfection. The amount of detergent added for purification of F/HN proteins was also crucial for hemolytic activity. The relevance of F/HN proteins in the gene-transfer capability of the cationic Sendai F/HN virosomes (CSVs) was verified by heat inactivation of the F/HN proteins, and cell-binding competition. DNA condensation by protamine sulfate was able to further enhance the transfection efficiency and serum resistance of CSV. The enhanced transfection efficiency of protamine-condensed DNA-encapsulating cationic Sendai F/HN virosomes (PCSVs) may result from specific and efficient cell binding mediated by F/HN proteins and efficient DNA encapsulation by protamine. The DNA condensation by protamine was crucial for systemic in vivo gene transfer by CSVs. The PCSVs exhibited a higher gene expression in various organs, especially the liver, compared to DOTAP/Chol lipoplexes. These results demonstrate the potential for the use of PCSV as gene delivery vehicles for systemic gene transfer.

Isolated Cerebellar Variant of Adrenoleukodystrophy with a de novo Adenosine Triphosphate-Binding Cassette D1 (ABCD1) Gene Mutation

X-linked adrenoleukodystrophy (X-ALD) shows a wide range of phenotypic expression, but clinical presentation as an isolated lesion of the cerebellar white matter and dentate nuclei has not been reported. We report an unusual presentation of X-ALD only with an isolated lesion of the cerebellar white matter and dentate nuclei. The proband, a 37-year-old man presented with bladder incontinence, slurred speech, dysmetria in all limbs, difficulties in balancing, and gait ataxia. Brain magnetic resonance imaging showed an isolated signal change of white matter around the dentate nucleus in cerebellum. With high level of very long chain fatty acid, gene study showed a de novo mutation in exon 1 at nucleotide position c.277_296dup20 (p.Ala100Cysfs*10) of the adenosine triphosphate-binding cassette D1 gene. It is advised to consider X-ALD as a differential diagnosis in patients with isolated cerebellar degeneration symptoms.

Preliminary Study of Neurodevelopmental Outcomes and Parenting Stress in Pediatric Mitochondrial Disease

BACKGROUND Little is known regarding the neuropsychological profiles of pediatric patients with mitochondrial diseases or their parents, information that is crucial for improving the quality of life (QOL) for both patients and parents. We aimed to delineate neurodevelopment and psychological comorbidity in children with mitochondrial diseases in the preliminary investigation of adequate intervention methods, better prognoses, and improved QOL for both patients and parents. METHODS Seventy children diagnosed with mitochondrial diseases were neuropsychologically evaluated. Neurocognitive (development, intelligence) and psychological (behavior, daily living function, maternal depression, parenting stress) functions were analyzed. Clinical variables, including the first symptom, epileptic classification, organ involvement, lactic acidosis, brain magnetic resonance imaging findings, muscle pathology, biochemical enzyme assay results, and syndromic diagnosis of mitochondrial diseases, were also reviewed. RESULTS Prediagnostic assessments indicated that cognitive and psychomotor developments were significantly delayed. Group mean full scale intelligence quotient (IQ) scores indicated mild levels of intellectual disability, borderline levels of verbal IQ impairment, and mild levels of intellectual disability on performance IQ. Many children exhibited clinically significant levels of behavioral problems, whereas mothers of children with mitochondrial diseases exhibited significant increases in parenting stress relative to mothers of healthy children. Furthermore, 65% of mothers exhibited significant levels of depression. Early onset of the first symptoms, diffuse brain atrophy, and drug-resistant epilepsy negatively influenced neurodevelopmental and adaptive functions. CONCLUSION Better understanding of the functional levels and profiles of neurodevelopment and psychological comorbidity in children with mitochondrial diseases in the prediagnostic period is essential for adequate support and QOL of children with mitochondrial diseases and their parents.

Long-term Outcome of Resective Epilepsy Surgery in Patients With Lennox-Gastaut Syndrome

In this study, we investigated the long-term seizure and adaptive function outcome of epilepsy surgery in patients with LGS. OBJECTIVE: We aimed to evaluate the long-term outcome of resective epilepsy surgery in patients with Lennox-Gastaut syndrome (LGS). METHODS: We reviewed the case reports of 90 patients with LGS who had undergone resective surgery between 2003 and 2014 at the Severance Children’s Hospital and managed them for a minimum period of 2 years. RESULTS: At the time of surgery, the patients were between 3.0 and 23.5 years old (mean ± SD: 9.3 ± 4.4). The time from seizure onset to surgery ranged from 0.7 to 20.1 years (7.2 ± 4.3). On postoperative follow-up for an average period of 6.1 ± 2.2 years (range: 2.1–11.4 years), 45 patients (50.0%) had no seizures, and 15 (16.7%) reported infrequent seizures. Seizure-free outcomes were achieved in 15 of the 21 (71.4%) hemispherectomies, 23 of the 51 (45.1%) multilobar resections, and 7 of the 18 (38.9%) single lobar resections. On high-resolution MRIs, 20 patients (22.2%) had negative findings, 8 of whom (40.0%) became seizure-free after resective surgery. Malformation of cortical development was the most common pathologic finding and was noted in 57 patients (63.3%). Seizure-free patients achieved better adaptive behavior and social competence than did patients with persistent seizures at the second (2–3 years after surgery) and third (4–6 years after surgery) follow-ups, as indicated by social quotients (P < .05). CONCLUSIONS: Resective surgery is a viable option in some patients to treat seizures that are associated with LGS, with a high probability of seizure control and better adaptive function.

Genotype-Phenotype Correlations in Pediatric Patients with Myotonic Dystrophy Type 1

Purpose Myotonic dystrophy, also known as dystrophia myotonica (DM), is an autosomal dominant disorder with 2 genetically distinct forms. DM type 1 (DM1) is the more common form and is caused by abnormal expansion of cytosine/thymine/guanine (CTG) repeats in the DM protein kinase (DMPK) gene. Our study aimed to determine whether the age of onset is correlated with CTG repeat length in a population of pediatric patients with DM1. Methods We retrospectively identified 30 pediatric patients with DM1 that underwent DMPK testing, of which the clinical data of 17 was sufficient. The cohort was divided into 2 subgroups based on the clinical phenotype (congenital-onset vs. late-onset) and number of CTG repeats (<1,000 vs. ≥1,000). Results We found no significant difference between the age of onset and CTG repeat length in our pediatric patient population. Based on clinical subgrouping, we found that the congenital-onset subgroup was statistically different with respect to several variables, including prematurity, rate of admission to neonatal intensive care unit, need for respiratory support at birth, hypotonia, dysphagia, ventilator dependence, and functional status on last visit, compared to the late-onset subgroup. Based on genetic subgrouping, we found a single variable (poor feeding in neonate) that was significantly different in the large CTG subgroup than that in the small CTG subgroup. Conclusion Clinical variables exhibiting statistically significant differences between the subgroups should be focused on prognosis and designing tailored management approaches for the patients; our findings will contribute to achieve this important goal for treating patients with DM1.