The gene encoding gigaxonin, a new member of the cytoskeletal BTB/kelch repeat family, is mutated in giant axonal neuropathy.

Disorganization of the neurofilament network is a prominent feature of several neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), infantile spinal muscular atrophy and axonal Charcot-Marie-Tooth disease. Giant axonal neuropathy (GAN, MIM 256850), a severe, autosomal recessive sensorimotor neuropathy affecting both the peripheral nerves and the central nervous system, is characterized by neurofilament accumulation, leading to segmental distension of the axons. GAN corresponds to a generalized disorganization of the cytoskeletal intermediate filaments (IFs), to which neurofilaments belong, as abnormal aggregation of multiple tissue-specific IFs has been reported: vimentin in endothelial cells, Schwann cells and cultured skin fibroblasts, and glial fibrillary acidic protein (GFAP) in astrocytes. Keratin IFs also seem to be alterated, as most patients present characteristic curly or kinky hairs. We report here identification of the gene GAN, which encodes a novel, ubiquitously expressed protein we have named gigaxonin. We found one frameshift, four nonsense and nine missense mutations in GAN of GAN patients. Gigaxonin is composed of an amino-terminal BTB (for Broad-Complex, Tramtrack and Bric a brac) domain followed by a six kelch repeats, which are predicted to adopt a beta-propeller shape. Distantly related proteins sharing a similar domain organization have various functions associated with the cytoskeleton, predicting that gigaxonin is a novel and distinct cytoskeletal protein that may represent a general pathological target for other neurodegenerative disorders with alterations in the neurofilament network.

A common pattern of brain MRI imaging in mitochondrial diseases with complex I deficiency.

OBJECTIVE: To identify a consistent pattern of brain MRI imaging in primary complex I deficiency. Complex I deficiency, a major cause of respiratory chain dysfunction, accounts for various clinical presentations, including Leigh syndrome. Human complex I comprises seven core subunits encoded by mitochondrial DNA (mtDNA) and 38 core subunits encoded by nuclear DNA (nDNA). Moreover, its assembly requires six known and many unknown assembly factors. To date, no correlation between genotypes and brain MRI phenotypes has been found in complex I deficiencies. DESIGN AND SUBJECTS: The brain MRIs of 30 patients carrying known mutation(s) in genes involved in complex I were retrospectively collected and compared with the brain MRIs of 11 patients carrying known mutations in genes involved in the pyruvate dehydrogenase (PDH) complex as well as 10 patients with MT-TL1 mutations. RESULTS: All complex I deficient patients showed bilateral brainstem lesions (30/30) and 77% (23/30) showed anomalies of the putamen. Supratentorial stroke-like lesions were only observed in complex I deficient patients carrying mtDNA mutations (8/19) and necrotising leucoencephalopathy in patients with nDNA mutations (4/5). Conversely, the isolated stroke-like images observed in patients with MT-TL1 mutations, or the corpus callosum malformations observed in PDH deficient patients, were never observed in complex I deficient patients. CONCLUSION: A common pattern of brain MRI imaging was identified with abnormal signal intensities in brainstem and subtentorial nuclei with lactate peak as a clue of complex I deficiency. Combining clinico-biochemical data with brain imaging may therefore help orient genetic studies in complex I deficiency.

Febrile brain stroke and tuberculous meningitis: persisting threat in non-endemic countries.

Tuberculous meningitis is uncommon in western countries and its outcome is poor when it is not diagnosed and treated in good time. Here, we present a case of febrile brain stroke revealing a tuberculous arachnoiditis in a 13-month-old infant living in a non-endemic country. Thanks to prompt specific antibiotherapy, the clinical outcome was globally favourable in spite of the occurrence of an asymptomatic brain tuberculoma, which disappeared spontaneously. Although tuberculous meningitis is rare in non-endemic countries, it must be evoked in strokes occurring in a febrile context.

Insidious peripheral neuropathy occurring under treatment in infantile MTHFR deficiency.

5,10-Methylenetetrahydrofolate reductase (MTHFR) deficiency was diagnosed in a 1-month-old baby with signs of cerebral distress. Under a classic treatment using methionine supplementation, methyl donor (betaine) folinic acid, vitamin B(6) and vitamin B(12), the neuromotor development was satisfactory. At 15 years of age, however, despite no clear modification of the biochemical markers in body fluids, she developed a clinically overt peripheral axonal neuropathy. Only partial clinical improvement was obtained after reinforcement of betaine doses. Surveillance of the peripheral nerve is indicated in MTHFR deficiency, including in the infantile form with a good therapeutic compliance.

[Arterial ischemic stroke in the healthy child. Practical approach (neonate and foetus excluded)]. / Accident artériel ischémique cérébral d'apparence primitive chez l'enfant. Démarche pratique (nouveau-né et foetus exclus).

Primary stroke can be due to embolism or an obstructive process of the vascular wall. Embolism may come from a parietal lesion of a large artery in the neck (traumatic dissections), from a cryptic cardiopathy, from a venous thrombosis associated with a right-left shunt. Among pathologies of endocranial arteries, the most frequent is the acute, postviral arteriopathy of the sus-clinoïd carotid, which evolves toward stabilisation or regression. Insidious obstructive arteriopathies of the Willis circle, including development of a transparenchymal suppletive circulation (Moya-Moya disease), cumulate chronic circulatory insufficiency and repetitive strokes. Inflammatory multifocal cerebral arteriopathies mainly involve mean and small arteries. Most of them are secondary to a multisystemic disease, but some are primary. The basic investigation is anatomical and begins with MRI. Emergency conventional cerebral angiography is discussed when heparinotherapy is difficult to decide (evolutive thrombosis), or when an endovascular intervention appears possible (anoeuvrism). Secondarily, conventional angiography is indicated in any chronic situation where a precise anatomical follow-up is necessary. Investigations of the cardiovascular system, of the thrombophilic risk, of a dysimmune process are discussed according to the clinico-anatomical diagnosis.

Survival motor neuron gene deletion in the arthrogryposis multiplex congenita-spinal muscular atrophy association.

The survival motor neuron (SMN) gene was lacking in 6/12 patients with arthrogryposis multiplex congenita (AMC) associated with spinal muscular atrophy (SMA). Neither point mutation in the SMN gene nor evidence for linkage to chromosome 5q13 were found in the other patients. Hitherto, arthrogryposis was regarded as an exclusion criterion in SMA. Our data strongly suggest that AMC of neurogenic origin is genetically heterogeneous, with a subgroup being allelic to SMA. Absence or interruption of the SMN gene in the AMC-SMA association will make the diagnosis easier and genetic counselling will now become feasible.

Mutation of the fumarase gene in two siblings with progressive encephalopathy and fumarase deficiency.

We report an inborn error of the tricarboxylic acid cycle, fumarase deficiency, in two siblings born to first cousin parents. They presented with progressive encephalopathy, dystonia, leucopenia, and neutropenia. Elevation of lactate in the cerebrospinal fluid and high fumarate excretion in the urine led us to investigate the activities of the respiratory chain and of the Krebs cycle, and to finally identify fumarase deficiency in these two children. The deficiency was profound and present in all tissues investigated, affecting the cytosolic and the mitochondrial fumarase isoenzymes to the same degree. Analysis of fumarase cDNA demonstrated that both patients were homozygous for a missense mutation, a G-955-->C transversion, predicting a Glu-319-->Gln substitution. This substitution occurred in a highly conserved region of the fumarase cDNA. Both parents exhibited half the expected fumarase activity in their lymphocytes and were found to be heterozygous for this substitution. The present study is to our knowledge the first molecular characterization of tricarboxylic acid deficiency, a rare inherited inborn error of metabolism in childhood.

[Spectacular neurologic manifestations after mild head trauma: retrospective study on 51 children]. / Manifestations neurologiques spectaculaires après traumatisme crânien bénin: étude rétrospective de 51 enfants.

UNLABELLED: Mild head traumas, as a rule, remain a- or paucisymptomatic. In a few cases however, spectacular manifestations develop despite absence of intracerebral lesion. POPULATION, METHODS: We have studied retrospectively 51 such children and contacted their family in order to clarify the follow-up. RESULTS: The dominant symptoms allowed to categorize the following situations: syncope-like loss of consciousness (11 cases), seizures (6), severe headaches with neurologic signs (15), confusion (8), visual disorders (6), amnesic ictus (5). Recurrences were possible but benign: in 8/11 children in the group "syncopes", in 1/6 in the group "seizures", in 5/21 in the 4 other groups. In the latter 4 groups, 11/21 children developed common migraine. Except for the only case who developed epilepsy later on, scholarship was normal in the 25 cases with sufficient follow-up. DISCUSSION: Beside syncopes and seizures, the long-lasting episodes suggested a migrainous pathogeny, perhaps at a maturative stage where the trigger of migrainous mechanism is at a low level in the brain. CONCLUSION: The mildness of the knock, the normality of CT scan including when the symptoms are present and the normality of both consciousness and examination once the symptoms have disappeared allow to avoid further investigations.

Allelic heterogeneity of SMARD1 at the IGHMBP2 locus.

Spinal Muscular Atrophy with Respiratory Distress (SMARD) is an autosomal recessive disorder characterized by neurogenic muscular atrophy due to progressive anterior horn cell degeneration and early life-threatening respiratory failure ascribed to diaphragmatic dysfunction. SMARD is clinically and genetically heterogeneous. SMARD type 1 is characterized by onset of respiratory failure within the first weeks of life and has been ascribed to mutations in the immunoglobulin mu-binding protein 2 (IGHMBP2) gene on chromosome 11q13-q21. We report here the identification of nine novel IGHMBP2 mutations in five SMARD1 patients, including seven missense [ c.587A>G (p.Gln196Arg), c.647C>T (p.Pro216Leu), c.752T>C (p.Leu251Pro), c.1693G>A (p.Asp565Asn), c.1730T>C (p.Leu577Pro), c.1807C>T (p.Arg603Cys), c.1909C>T (p.Arg637Cys)] and two nonsense mutations [ c.1488C>A (p.Cys496X), c.2368C>T (p.Arg790X)]. Interestingly, 7 of 9 mutations occurred at highly conserved residues of the putative DNA helicase domain. The identification of novel IGHMBP2 variants will hopefully help diagnosing SMARD1 and contribute to a better functional characterization of IGHMBP2 gene product.

Somatic mosaicism for partial paternal isodisomy in Wiedemann-Beckwith syndrome: a post-fertilization event.

Genomic imprinting has been implicated in the aetiology of an overgrowth cancer-prone syndrome, the Wiedemann-Beck-with syndrome (WBS). We have demonstrated uniparental disomy (UPD) for paternal chromosome 11p markers in 5 out of 25 sporadic cases (20%). Delineation of the extent of the disomy region may help in understanding the mechanism and the stage, meiotic or mitotic, of disomy formation in this disease and in associated tumours. Our current studies in WBS patients with seventeen 11p and one 11q markers reveal paternal isodisomy, not heterodisomy, in the five cases. For one case we demonstrate unambiguously that partial isodisomy for 11p and somatic mosaicism for UPD resulted from a post-fertilization event. The restriction of isodisomy to part of 11p in another case, and somatic mosaicism for UPD in three other cases, suggest a mitotic recombinational event that must have occurred after fertilization. Mosaic phenotypes reflect the timing of their origin and the fate of the cells involved, as well as the cell-specific pattern of imprinting. Somatic mosaicism for UPD in four cases may thus explain the incomplete forms of WBS. The association of hemihypertrophy in sporadic WBS and even some cases of isolated hemihypertrophy. This is in agreement with a recent report of paternal isodisomy for 11p markers in a patient with hemihypertrophy, Wilms' tumour and adrenocortical carcinoma. Moreover, the risk of developing a tumour seems higher (50%) for patients with paternal 11p UPD than for WBS patients in general (7.5%).

Giant axonal neuropathy locus refinement to a < 590 kb critical interval.

Giant axonal neuropathy (GAN) is a rare autosomal recessive neurodegenerative disorder, characterised clinically by the development of chronic distal polyneuropathy during childhood, mental retardation, kinky or curly hair, skeletal abnormalities and, ultrastructurally, by axons in the central and peripheral nervous systems distended by masses of tightly woven neurofilaments. We recently localised the GAN locus in 16q24.1 to a 5-cM interval between the D16S507 and D16S511 markers by homozygosity mapping in three consanguineous Tunisian families. We have now established a contig-based physical map of the region comprising YACs and BACs where we have placed four genes, ten ESTs, three STSs and two additional microsatellite markers, and where we have identified six new SSCP polymorphisms and six new microsatellite markers. Using these markers, we have refined the position of our previous flanking recombinants. We also identified a shared haplotype between two Tunisian families and a small region of homozygosity in a Turkish family with distant consanguinity, both suggesting the occurrence of historic recombinations and supporting the conclusions based on the phase-known recombinations. Taken together, these results allow us to establish a transcription map of the region, and to narrow down the GAN position to a < 590 kb critical interval, an important step toward the identification of the defective gene.

Organization of the mevalonate kinase (MVK) gene and identification of novel mutations causing mevalonic aciduria and hyperimmunoglobulinaemia D and periodic fever syndrome.

Mevalonic aciduria (MA) and hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS) are two autosomal recessive inherited disorders both caused by a deficient activity of the enzyme mevalonate kinase (MK) resulting from mutations in the encoding MVK gene. Thus far, disease-causing mutations only could be detected by analysis of MVK cDNA. We now describe the genomic organization of the human MVK gene. It is 22 kb long and contains 11 exons of 46 to 837 bp and 10 introns of 379 bp to 4.2 kb. Three intron-exon boundaries were confirmed from natural splice variants, indicating the occurrence of exon skipping. Sequence analysis of 27 HIDS and MA patients confirmed all previously reported genotypes based on cDNA analysis and identified six novel nucleotide substitutions resulting in missense or nonsense mutations, providing new insights in the genotype/phenotype relation between HIDS and MA.

Extensive macrogyri or no visible gyri: distinct clinical, electroencephalographic, and genetic features according to different imaging patterns.

We studied 43 children with extensive brain gyral anomalies diagnosed radiologically and defined by (a) the absence or paucity of sulci over cortical areas affecting at least two lobes in each hemisphere, and (b) the absence or reduction of interdigitation between gray and white matter. We correlated the clinical, EEG, and genetic findings with the imaging features. A seemingly homogeneous group of patients (group A, n = 30) presented a common imaging pattern characterized by four features: (1) a thickened neocortex, (2) widened lateral ventricles, (3) apparent verticalization and widening of sylvian fissures, and (4) bilateral and symmetric distribution of the abnormalities. Another group of patients (group B, n = 13) exhibited heterogeneous imaging anomalies, termed "nonlissencephalic brain malformation," differing in at least one of the following four ways from the radiologic criteria defining group A: absence of verticalization of sylvian fissures (n = 12), thin neocortex (n = 2), normal-size lateral ventricles (n = 2), and asymmetric brain defects (n = 3). In group A, some clinical features had a significantly lower frequency (p < or = 0.01) than in group B: microcephaly, a complete lack of postural development, and intractable epilepsy. There was a significant relationship, but only in group A, between the degree of gyral anomalies and the extent of neurodevelopmental delay. Some EEG patterns (rapid rhythms and delta-theta rhythms) were highly specific for the group A patients. There was lower risk of familial recurrence in group A (recurrence of convolutional anomalies was 3.5% of sibship in group A versus 44% of sibship in group B, p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Extensive brain calcifications, leukodystrophy, and formation of parenchymal cysts: a new progressive disorder due to diffuse cerebral microangiopathy.

A new cerebral disorder, described in three unrelated children, has recognizable clinical, radiologic, and neuropathologic findings. The onset occurs from early infancy to adolescence with slowing of cognitive performance, rare convulsive seizures, and a mixture of extrapyramidal, cerebellar, and pyramidal signs. CT shows progressive calcifications in the basal and cerebellar gray nuclei and the central white matter. MRI reveals diffuse abnormal signals of the white matter on T2-weighted sequences. A special feature is the development of parenchymal cysts in the cerebellum and the supratentorial compartment, leading to compressive complications and surgical considerations. Neuropathologic examination of surgically removed pericystic samples reveals angiomatous-like rearrangements of the microvessels, together with degenerative secondary changes of other cellular elements. Both the anatomic findings and the course of the disease suggest a constitutional, diffuse cerebral microangiopathy resulting in microcystic, then macrocystic, parenchymal degeneration.

Haemorrhagic shock and encephalopathy syndrome: neurological course and predictors of outcome.

UNLABELLED: The haemorrhagic shock and encephalopathy syndrome (HSES) is a devastating disease. The aetiology of this syndrome is unknown, and, despite intensive treatment, the outcome is often fatal or associated with severe neurological sequelae. OBJECTIVE: To assess the neurological features and potential prognostic markers of the disease. DESIGN: Retrospective study. SETTING: Division of Neuropaediatrics in a children's university hospital. PATIENTS AND METHODS: Fourteen patients fulfilling the HSES criteria out of 42 children admitted with fever and shock to the Paediatric Intensive Care Unit between 1986 and 1994, were analysed for clinical, biological, neuroradiological, EEG and neuropathological findings. RESULTS: The patients (age range from 2 to 33 months) were found at night or in the morning either comatous (n = 3) or convulsing (n = 11). All but one were healthy before admission, although eight had had a brief prodromal infectious disease. All were febrile (mean body temperature 39.9 degrees C +/-0.9 degrees). Seasonal clustering during the winter months was observed. Coma and seizures with frequent status epilepticus were the main neurological manifestations. All children recovered from their multiple organ failure within a few days. Seven died (50%); four survivors had neurological sequelae (29%) with a developmental quotient (DQ) of 50% or less in three and a DQ of 75% in one and three infants (21%) had normal outcomes. Computed tomography (CT) displayed a diffuse area of low density mainly in the cerebral cortex and intraventricular and parenchymal haemorrhages. Magnetic resonance imaging (MRI) showed haemorrhagic cortical lesions. Postmortem examination of the brain conducted in three patients showed necrotic and haemorrhagic lesions, mainly in cortical areas. Comparison of the children with adverse outcome (death or neurological sequelae) with those with normal outcome revealed that predictors of poor outcome were status epilepticus (p = 0.003) and coma for more than 24 h (p = 0.01). Infants without disseminated intravascular coagulation, without a biphasic course and without brain hypodensities or haemorrhages on CT scans performed at least 4 days after onset had a normal neurodevelopmental outcome. CONCLUSION: The central nervous system appeared to be the main target of the HSES lesions. The most common outcome was brain death or severe brain damage. Further studies with a larger sample are necessary to determine whether the prognostic indicators we identified are reliable.

Infantile neuropathy with unstable myelin: study of the P0 protein.

An unusual form of hereditary motor and sensory neuropathy characterized by a prominent disruption of the myelin lamellae is reported. In addition to detailed morphological analysis, we investigated the protein P0, which is the major protein of peripheral myelin involved in adhesion. No major gene rearrangement and no differences in P0 protein expression were observed in the present case.

Central nervous system lesions in hypomelanosis of Ito: an MRI and pathological study.

A severe form of hypomelanosis of Ito is reported, which presented as fetal macrocephaly and neonatal epileptic encephalopathy. Lymphocyte karyotypes were normal. MRI showed an absence of delineation between cortical grey matter and white matter. The prominent neuropathological finding was an abnormal cortical morphogenesis, with the co-existence of cells migrating normally and cells exhibiting arrêt en route or even the complete absence of migration. Intense astrocytic reaction with moderate dystrophic features was present. Juxtaposition of two migration behaviours in the neural cells paralleled the cutaneous findings and reinforced the hypothesis of a genetic chimerism.

Mitotic spindle fiber orientation in relation to cell migration in the neo-cortex of normal and reeler mouse.

The angular distribution of mitotic spindle fibers has been studied in the telencephalic ventricular zone (VZ) of mouse embryos and has been found to be monophasic and invariant during the early cortical histogenesis both in the normal and in a reeler embryo. This observation suggests that the orientation of mitotic spindle fibers is independent of nerve cell migration in the embryonic cortex.

[Quantitative study of isolated nerve fibers in alcoholic neuropathy (author's transl)]. / Etude quantitative des fibres nerveuses isolees dans les polynevrites alcooliques.

This is a report of qualitative and quantitative study of nerve fibres in alcoholic neuropathy. In order to determine the frequency of segmental demyelination in alcoholic neuropathy, 10 nerve biopsies from 9 patients were studied by teasing; 100 consecutive fibres were isolated from each nerve and classified according to their morphology. This study confirms that segmental demyelination is a rare finding in this condition. Segmental demyelination of peripheral nerve fibres occurred in three cases and affected 6 to 8 per cent of the fibres. Wallerian degeneration of nerve fibres was found in all ten nerve biopsy specimens and affected 31 to 98 percent of the isolated fibres.

Treatment of vein of Galen aneurysmal malformation.

The authors report the case of a vein of Galen aneurysmal malformation in a 1-year-old baby presenting with an enlarging head. The lesion was a direct arteriovenous fistula in a dilated vein of Galen and was treated by complete embolization in one session. Four months after occlusion of the shunt, the ectatic vein of Galen and torcular were normal, and the head circumference had stabilized. This case serves as an opportunity to emphasize the quality of results that can be obtained with endovascular techniques. Proper analysis of the vein of Galen angioarchitecture allows planning for appropriate treatment with the lowest possible risk of morbidity and mortality.