Development and implementation of a novel assay for L-2-hydroxyglutarate dehydrogenase (L-2-HGDH) in cell lysates: L-2-HGDH deficiency in 15 patients with L-2-hydroxyglutaric aciduria.

L-2-hydroxyglutaric aciduria (L-2-HGA) is a rare inherited autosomal recessive neurometabolic disorder caused by mutations in the gene encoding L-2-hydroxyglutarate dehydrogenase. An assay to evaluate L-2-hydroxyglutarate dehydrogenase (L-2-HGDH) activity in fibroblast, lymphoblast and/or lymphocyte lysates has hitherto been unavailable. We developed an L-2-HGDH enzyme assay in cell lysates based on the conversion of stable-isotope-labelled L-2-hydroxyglutarate to 2-ketoglutarate, which is converted into L-glutamate in situ. The formation of stable isotope labelled L-glutamate is therefore a direct measure of L-2-HGDH activity, and this product is detected by liquid chromatography-tandem mass spectrometry. A deficiency of L-2-HGDH activity was detected in cell lysates from 15 out of 15 L-2-HGA patients. Therefore, this specific assay confirmed the diagnosis unambiguously affirming the relationship between molecular and biochemical observations. Residual activity was detected in cells derived from one L-2-HGA patient. The L-2-HGDH assay will be valuable for examining in vitro riboflavin/FAD therapy to rescue L-2-HGDH activity.

The burden of paediatric stroke and cerebrovascular disorders in Croatia.

Pediatric stroke is significantly less common than stroke in adults, but represents a major challenge to public health authorities. The aim of this retrospective study was to identify the total and annual number of children younger than 18 years with arterial ischaemic stroke and transient ischaemic attack referred to the Children's Hospital Zagreb, which is a major national centre specialised for the treatment and prevention of stroke in children. We reviewed the medical records of the Department of Neuropediatrics database at the Children's Hospital Zagreb between 1998-2005 in order to provide demographic and clinical characteristics and neuroimaging findings in children with arterial ischaemic stroke. In the 7-year period, we identified a total of 124 children from different geographic areas of Croatia with a confirmed diagnosis of transient ischaemic attack (N=77), and arterial ischaemic stroke (N=47). Perinatal and childhood arterial ischaemic stroke were equally represented (23 and 24 children, respectively). The average number of new cases identified each year was 18 cases (range: 12-21), seven arterial ischaemic stroke and 11 transient ischaemic attack cases. Male predominance was found in children with arterial ischaemic stroke with a male : female ratio of 1.76 : 1, and was slightly higher in childhood arterial ischaemic stroke compared with perinatal arterial ischaemic stroke (2 : 1 and 1.56 : 1, respectively). In contrast, transient ischaemic attack was more frequently found in girls, and more likely identified in older children compared with younger children with arterial ischaemic stroke. Obtained data will contribute to better understanding of paediatric stroke in Croatia and will provide a base for the establishment of the national referral center and national pediatric stroke registry.

Cystic leukoencephalopathy without megalencephaly: a distinct disease entity in 15 children.

OBJECTIVE: To describe a distinctive syndrome of nonprogressive encephalopathy, normo- or microcephaly, and early onset of severe psychomotor impairment in 15 white patients, including two siblings and two first cousins. METHODS AND RESULTS: MRI revealed bilateral cysts in the anterior part of the temporal lobe and white matter abnormalities with pericystic abnormal myelination and symmetric lesions in frontal and occipital periventricular regions. None of the usual inborn errors of metabolism/infectious diseases associated with leukoencephalopathy and bilateral anterior temporal lobe cysts were detected. CONCLUSIONS: These patients' clinical signs and cranial MRI abnormalities are strikingly similar and may represent a distinctive disease with autosomal-recessive inheritance: cystic leukoencephalopathy without megalencephaly.

Cytochrome c oxidase partial deficiency-associated Leigh disease presenting as an extrapyramidal syndrome.

Leigh disease is a subacute neurodegenerative disorder characterized by symmetric necrotic lesions in the basal ganglia, cerebellum, thalamus, brain stem, and optical nerves and caused by altered oxidative phosphorylation. We describe the clinical, biochemical, neuroimaging, and molecular studies of a 19-year-old boy with early-onset Leigh disease manifesting as severe extrapyramidal disorder with generalized dystonia and choreoathetosis. He was born of healthy parents after an uneventful pregnancy and delivery. At the age of 2 1/2 years, after a minor respiratory infection, he developed unstable, broad-based gait and tremor of the hands. These symptoms persisted for the next several years, when ataxia became more prominent. Difficulty in swallowing, dysarthria, trunk dystonia, and marked dyskinesia of the arms and hands gradually developed. Nystagmus, transient ptosis, and strabismus also appeared. Abnormal laboratory findings included elevated plasma and cerebrospinal fluid lactate and pyruvate, with an abnormal lactate/pyruvate ratio. Cranial computed tomography and magnetic resonance imaging demonstrated signs of cerebellar atrophy, bilateral and symmetric hypodensities in the lentiform nucleus and thalamus, and transient hyperintensities of cerebral peduncles in T2-weighted sequences suggestive of Leigh disease. Muscle biopsy revealed isolated fiber atrophy, necrotic fibers undergoing phagocytosis, and no ragged-red fibers. The measured catalytic activity of cytochrome c oxidase in skeletal muscle homogenates demonstrated a partial cytochrome c oxidase deficiency No abnormalities in the mitochondrial genome and in the SURF-1 gene were found. The boy is currently receiving levodopa therapy, creatine monohydrate, and a high dosage of thiamine and lipoic acid, his condition is stabilized, and extrapyramidal symptoms are less pronounced.

Mutations of MLC1 (KIAA0027), encoding a putative membrane protein, cause megalencephalic leukoencephalopathy with subcortical cysts.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive disorder characterized by macrocephaly, deterioration of motor functions with ataxia, and spasticity, eventuating in mental decline. The brain appears swollen on magnetic resonance imaging, with diffuse white-matter abnormalities and the invariable presence of subcortical cysts. MLC was recently localized on chromosome 22q(tel). We have narrowed down the critical region by linkage analysis of 11 informative families with MLC to a region of approximately 250 kb, containing four known genes. One family with two patients who were siblings did not display linkage between the MLC phenotype and any of the analyzed microsatellite markers on chromosome 22q(tel), suggesting genetic heterogeneity and the existence of at least a second MLC locus. The maximum two-point LOD score for the 11 families was 6.6 at recombination fraction .02. Twelve different mutations in seven informative and six uninformative families were found in one of the candidate genes, KIAA0027, which we renamed "MLC1." The gene encodes a putative membrane protein with eight predicted transmembrane domains. The patients of one family were compound heterozygotes for mutations that both introduced stop codons. The mutations further included frameshifts, splice-acceptor mutations, a putative splice-donor mutation, and amino acid substitutions of residues in predicted transmembrane domains. These data provide strong evidence that mutations of MLC1 cause the disease.

Megalencephalic leukoencephalopathy: a further case of a new neurodegenerative white matter disease.

The case is presented of a 4.5-year-old boy with cystic megalencephalic leukoencephalopathy who met the diagnostic criteria of a recently described neurodegenerative white matter disorder, i.e. leukoencephalopathy with swelling and a discrepantly mild clinical course (van der Knaap 1995). He demonstrated an extremely mild and slowly progressive clinical course with near normal psychomotor development, particularly of mental functions, which contrasted with somewhat disturbed gross and fine motor skills. Repeated CT and MRI scanning showed extensive hemispheral cerebral white matter changes and demonstrated predominant frontal involvement of the periventricular and subcortical white matter. MRI was more sensitive in the detection of preserved structures, i.e. occipital subcortical and central white matter, as well as in the visualisation of swelling and cystic lesions in the tip of the temporal lobes, which represent the hallmark of this entity. Thus, MRI is an essential diagnostic tool for this entity.

Cystic leukoencephalopathy in a megalencephalic child: clinical and magnetic resonance imaging/magnetic resonance spectroscopy findings.

A neurodegenerative disorder characterized by megalencephaly since early infancy and slowly progressive symptoms of cerebellar, pyramidal, and extrapyramidal dysfunction, pseudobulbar signs, and epilepsy was detected in an 8-year-old girl with severe neuromotor handicap but preservation of mental and sensory functions. Cranial computed tomography and magnetic resonance imaging revealed brain swelling as well as severe abnormalities of frontal, temporal, and parietal white matter, with an extended cystlike appearance isointense to cerebrospinal fluid. Localized proton magnetic resonance spectroscopy of affected cystic white matter showed a loss of all metabolites, in accordance with a complete disintegration of neuroaxonal and glial tissue. This case is likely a severe variant of a recently described megalencephalic leukoencephalopathy with swelling and discrepantly mild clinical course.

Personality traits in school children with epilepsy.

An alternative way of looking at epilepsy has been restricted to the observation of personality characteristics and behavioral cognitive impairments, as these are the most important secondary handicaps. The term "behavioural disorders" is connected with the problem of the development of personality. For this reason, in clinical work a sensitive and standardized psychometric instruments for measuring personality constructs are required. One of the most frequent used instruments in our child neurowork is Eysenck's Personality Inventory (EPI--junior questionnaire), based on Eysenck's theory. In this study, EPI-junior questionnaire was given to a group of 60 boys and girls aged 10-14 years with various forms of epilepsy (single partial seizures--N = 28; complex partial seizures--N = 18; typical absence--N = 8; atypical absence--N = 6. All children were receiving anticonvulsant drugs in doses within or below therapeutic limits. The possible influence of drug administration on personality characteristics of these children was not specifically analyzed for insufficient data in their medical histories. Results of personality characteristics obtained on the EPI junior test of the children with epilepsy were compared to the results of "normal" school children matched by age, sex and social conditions. Its was found (on the "extroversion-introversion" scale) that the children with epilepsy were more introverted than the control group children, which is contrary to the common clinical experience. On the other hand, there were no statistical differences between these two groups in the category of "neuroticism". Finally, the children with epilepsy had significantly higher results on the "lie scale", which indicated greater unreliability of their results obtained on EPI-junior "lie" scale as compared to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypoxic-ischemic brain damage in term neonates--the relation of neurodevelopmental handicap to cranial ultrasound findings.

This study presents ultrasound findings and neurodevelopmental follow-up in ten infants born at term suffering most severe grade of hypoxic-ischemic encephalopathy. Early ultrasound findings showed in nine of these ten neonates signs of cerebral edema accompanied in two children by intraventricular haemorrhage. Late ultrasound findings in all infants examined demonstrated severe cerebral atrophy, predominantly affecting the cortico-subcortical area. In three children multiple subcortical cysts were also present, corresponding to ultrasound findings of subcortical leukomalacia. Cranial computerized tomography was performed in six of the ten children, showing more precisely the predominant site of cortical atrophy, whereas in children with ultrasound findings of subcortical leukomalacia extensive low density areas in the subcortical white matter were present. All children had neurodevelopmental follow-up for between two and seven years. Six of the ten children have multiple disabilities suffering from spastic quadriparesis, epilepsy, mental retardation and/or visual disability. Among these six were all three children with subcortical leukomalacia. All the children demonstrated poor head growth and became markedly microcephalic. We consider ultrasonography to be very useful in the diagnosis of hypoxic-ischemic brain damage in term neonates as well in predicting the neurodevelopmental outcome in asphyxiated term infants.