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1.
Brain ; 142(1): 59-69, 2019 01 01.
Article in English | MEDLINE | ID: mdl-30561534

ABSTRACT

Kufs disease is the major adult form of neuronal ceroid lipofuscinosis, but is rare and difficult to diagnose. Diagnosis was traditionally dependent on the demonstration of characteristic storage material, but distinction from normal age-related accumulation of lipofuscin can be challenging. Mutation of CLN6 has emerged as the most important cause of recessive Kufs disease but, remarkably, is also responsible for variant late infantile ceroid lipofuscinosis. Here we provide a detailed description of Kufs disease due to CLN6 pathogenic variants. We studied 20 cases of Kufs disease with CLN6 pathogenic variants from 13 unrelated families. Mean age of onset was 28 years (range 12-51) with bimodal peaks in teenage and early adult life. The typical presentation was of progressive myoclonus epilepsy with debilitating myoclonic seizures and relatively infrequent tonic-clonic seizures. Patients became wheelchair-bound with a mean 12 years post-onset. Ataxia was the most prominent motor feature. Dementia appeared to be an invariable accompaniment, although it could take a number of years to manifest and occasionally cognitive impairment preceded myoclonic seizures. Patients were usually highly photosensitive on EEG. MRI showed progressive cerebral and cerebellar atrophy. The median survival time was 26 years from disease onset. Ultrastructural examination of the pathology revealed fingerprint profiles as the characteristic inclusions, but they were not reliably seen in tissues other than brain. Curvilinear profiles, which are seen in the late infantile form, were not a feature. Of the 13 unrelated families we observed homozygous CLN6 pathogenic variants in four and compound heterozygous variants in nine. Compared to the variant late infantile form, there was a lower proportion of variants that predicted protein truncation. Certain heterozygous missense variants in the same amino acid position were found in both variant late infantile and Kufs disease. There was a predominance of cases from Italy and surrounding regions; this was partially explained by the discovery of three founder pathogenic variants. Clinical distinction of type A (progressive myoclonus epilepsy) and type B (dementia with motor disturbance) Kufs disease was supported by molecular diagnoses. Type A is usually caused by recessive pathogenic variants in CLN6 or dominant variants in DNAJC5. Type B Kufs is usually associated with recessive CTSF pathogenic variants. The diagnosis of Kufs remains challenging but, with the availability of genetic diagnosis, this will largely supersede the use of diagnostic biopsies, particularly as biopsies of peripheral tissues has unsatisfactory sensitivity and specificity.


Subject(s)
Membrane Proteins/genetics , Neuronal Ceroid-Lipofuscinoses/diagnosis , Neuronal Ceroid-Lipofuscinoses/genetics , Adolescent , Adult , Age of Onset , Aged , Brain/ultrastructure , Female , Humans , Male , Middle Aged , Mutation , Neuronal Ceroid-Lipofuscinoses/diagnostic imaging , Neuronal Ceroid-Lipofuscinoses/pathology , Survival Rate , Young Adult
2.
Am J Med Genet A ; 179(12): 2343-2356, 2019 12.
Article in English | MEDLINE | ID: mdl-31660690

ABSTRACT

Polymicrogyria (PMG) is a heterogeneous brain malformation that may result from prenatal vascular disruption or infection, or from numerous genetic causes that still remain difficult to identify. We identified three unrelated patients with polymicrogyria and duplications of chromosome 2p, defined the smallest region of overlap, and performed gene pathway analysis using Cytoscape. The smallest region of overlap in all three children involved 2p16.1-p16.3. All three children have bilateral perisylvian polymicrogyria (BPP), intrauterine and postnatal growth deficiency, similar dysmorphic features, and poor feeding. Two of the three children had documented intellectual disability. Gene pathway analysis suggested a number of developmentally relevant genes and gene clusters that were over-represented in the critical region. We narrowed a rare locus for polymicrogyria to a region of 2p16.1-p16.3 that contains 33-34 genes, 23 of which are expressed in cerebral cortex during human fetal development. Using pathway analysis, we showed that several of the duplicated genes contribute to neurodevelopmental pathways including morphogen, cytokine, hormonal and growth factor signaling, regulation of cell cycle progression, cell morphogenesis, axonal guidance, and neuronal migration. These findings strengthen the evidence for a novel locus associated with polymicrogyria on 2p16.1-p16.3, and comprise the first step in defining the underlying genetic etiology.


Subject(s)
Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Chromosome Duplication , Chromosomes, Human, Pair 2 , Genetic Association Studies , Genetic Predisposition to Disease , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Malformations of Cortical Development/diagnosis , Malformations of Cortical Development/genetics , Adolescent , Brain/abnormalities , Brain/diagnostic imaging , Comparative Genomic Hybridization , Computational Biology/methods , Facies , Female , Humans , Infant, Newborn , Magnetic Resonance Imaging , Male , Phenotype
3.
Ann Neurol ; 81(5): 677-689, 2017 May.
Article in English | MEDLINE | ID: mdl-28380698

ABSTRACT

OBJECTIVE: To comprehensively describe the new syndrome of myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK), including cellular electrophysiological characterization of observed clinical improvement with fever. METHODS: We analyzed clinical, electroclinical, and neuroimaging data for 20 patients with MEAK due to recurrent KCNC1 p.R320H mutation. In vitro electrophysiological studies were conducted using whole cell patch-clamp to explore biophysical properties of wild-type and mutant KV 3.1 channels. RESULTS: Symptoms began at between 3 and 15 years of age (median = 9.5), with progressively severe myoclonus and rare tonic-clonic seizures. Ataxia was present early, but quickly became overshadowed by myoclonus; 10 patients were wheelchair-bound by their late teenage years. Mild cognitive decline occurred in half. Early death was not observed. Electroencephalogram (EEG) showed generalized spike and polyspike wave discharges, with documented photosensitivity in most. Polygraphic EEG-electromyographic studies demonstrated a cortical origin for myoclonus and striking coactivation of agonist and antagonist muscles. Magnetic resonance imaging revealed symmetrical cerebellar atrophy, which appeared progressive, and a prominent corpus callosum. Unexpectedly, transient clinical improvement with fever was noted in 6 patients. To explore this, we performed high-temperature in vitro recordings. At elevated temperatures, there was a robust leftward shift in activation of wild-type KV 3.1, increasing channel availability. INTERPRETATION: MEAK has a relatively homogeneous presentation, resembling Unverricht-Lundborg disease, despite the genetic and biological basis being quite different. A remarkable improvement with fever may be explained by the temperature-dependent leftward shift in activation of wild-type KV 3.1 subunit-containing channels, which would counter the loss of function observed for mutant channels, highlighting KCNC1 as a potential target for precision therapeutics. Ann Neurol 2017;81:677-689.


Subject(s)
Ataxia , Cognitive Dysfunction/etiology , Epilepsies, Myoclonic , Hot Temperature , Shaw Potassium Channels/metabolism , Adolescent , Adult , Age of Onset , Ataxia/complications , Ataxia/diagnostic imaging , Ataxia/genetics , Ataxia/physiopathology , Electroencephalography , Epilepsies, Myoclonic/complications , Epilepsies, Myoclonic/diagnostic imaging , Epilepsies, Myoclonic/genetics , Epilepsies, Myoclonic/physiopathology , Female , HEK293 Cells , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Mutation , Pedigree , Shaw Potassium Channels/genetics , Syndrome , Young Adult
4.
Ann Neurol ; 77(4): 675-83, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25623524

ABSTRACT

OBJECTIVE: The DEPDC5 (DEP domain-containing protein 5) gene, encoding a repressor of the mTORC1 signaling pathway, has recently emerged as a major gene mutated in familial focal epilepsies. We aimed to further extend the role of DEPDC5 to focal cortical dysplasias (FCDs). METHODS: Seven patients from 4 families with DEPDC5 mutations and focal epilepsy associated with FCD were recruited and investigated at the clinical, neuroimaging, and histopathological levels. The DEPDC5 gene was sequenced from genomic blood and brain DNA. RESULTS: All patients had drug-resistant focal epilepsy, 5 of them underwent surgery, and 1 had a brain biopsy. Electroclinical phenotypes were compatible with FCD II, although magnetic resonance imaging (MRI) was typical in only 4 cases. Histopathology confirmed FCD IIa in 2 patients (including 1 MRI-negative case) and showed FCD I in 2 other patients, and remained inconclusive in the last 2 patients. Three patients were seizure-free postsurgically, and 1 had a worthwhile improvement. Sequencing of blood DNA revealed truncating DEPDC5 mutations in all 4 families; 1 mutation was found to be mosaic in an asymptomatic father. A brain somatic DEPDC5 mutation was identified in 1 patient in addition to the germline mutation. INTERPRETATION: Germline, germline mosaic, and brain somatic DEPDC5 mutations may cause epilepsy associated with FCD, reinforcing the link between mTORC1 pathway and FCDs. Similarly to other mTORopathies, a "2-hit" mutational model could be responsible for cortical lesions. Our study also indicates that epilepsy surgery is a valuable alternative in the treatment of drug-resistant DEPDC5-positive focal epilepsies, even if the MRI is unremarkable.


Subject(s)
Epilepsies, Partial/diagnosis , Epilepsies, Partial/genetics , Malformations of Cortical Development/diagnosis , Malformations of Cortical Development/genetics , Mutation/genetics , Repressor Proteins/genetics , Adolescent , Adult , Child , Female , GTPase-Activating Proteins , Humans , Male , Middle Aged , Pedigree , Young Adult
5.
Epilepsia ; 57(2): 210-21, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26666500

ABSTRACT

OBJECTIVE: To evaluate efficacy, tolerability, and safety of adjunctive brivaracetam (BRV) in patients with Unverricht-Lundborg disease (EPM1). METHODS: Two prospective, multicenter, double-blind, phase III trials (N01187/NCT00357669; N01236/NCT00368251) in patients (≥16 years) with genetically ascertained EPM1, showing moderate-severe myoclonus (action myoclonus score ≥30/160), randomized (1:1:1) to twice-daily BRV (N01187: 50 or 150 mg/day; N01236: 5 or 150 mg/day), or placebo. Both studies comprised a baseline period (2 weeks), 2-week up-titration period, 12-week stable-dose maintenance period, and down-titration or entry into long-term follow-up study. Symptoms of myoclonus were assessed by Unified Myoclonus Rating Scale (UMRS). Primary efficacy end point was percent reduction from baseline in action myoclonus score (UMRS section 4) at last treatment visit. Safety assessments included treatment-emergent adverse events (TEAEs). RESULTS: N01187: 50 patients randomized, 47 completed; N01236: 56 patients randomized, 54 completed. Median (min-max) percent reduction from baseline in action myoclonus score is the following-N01187: placebo 5.6 (-81.3 to 53.8), pooled BRV group (primary efficacy analysis) 21.4 (-50.0 to 73.6), BRV 50 mg/day 26.3 (-35.8 to 69.2), BRV 150 mg/day 16.9 (-50.0 to 73.6); N01236: placebo 17.5 (-170 to 61.5), BRV 5 mg/day -4.6 (-430 to 81.8), BRV 150 mg/day (primary efficacy analysis) 12.3 (-58.3 to 96.9). Estimated differences versus placebo were not statistically significant. TEAEs were reported by 72-75% placebo-treated and 56-83% BRV-treated patients. SIGNIFICANCE: Effect of BRV on action myoclonus was not statistically significant. However, action myoclonus score showed wide intrapatient variability and may not have been the optimal tool to measure severity of myoclonus in EPM1. Both studies had very high completion rates (95.3% overall), and a high percentage of patients (88.7% overall) entered long-term follow-up; both likely to be influenced by good tolerability. These studies demonstrate the feasibility of rigorous trials in progressive myoclonic epilepsy.


Subject(s)
Anticonvulsants/therapeutic use , Pyrrolidinones/therapeutic use , Unverricht-Lundborg Syndrome/drug therapy , Adolescent , Adult , Clonazepam/therapeutic use , Dose-Response Relationship, Drug , Double-Blind Method , Drug Therapy, Combination , Female , Fructose/analogs & derivatives , Fructose/therapeutic use , Humans , Isoxazoles/therapeutic use , Levetiracetam , Male , Middle Aged , Phenobarbital/therapeutic use , Piracetam/analogs & derivatives , Piracetam/therapeutic use , Topiramate , Treatment Outcome , Valproic Acid/therapeutic use , Young Adult , Zonisamide
6.
Dev Med Child Neurol ; 58(1): 39-48, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26179148

ABSTRACT

AIM: Polymicrogyria (PMG) is one of the most common forms of cortical malformation yet the mechanism of its development remains unknown. This study describes the histopathological aspects of PMG in a large series including a significant proportion of fetal cases. METHOD: We have reviewed the neuropathology and medical records of 44 fetuses and 27 children and adults in whom the cortical architecture was focally or diffusely replaced by one or more festooning bands of neurons. RESULTS: The pial surface of the brain overlying the polymicrogyric cortex was abnormal in almost 90% of cases irrespective of the aetiology. This accords with animal studies indicating the importance of the leptomeninges in cortical development. The aetiology of PMG was highly heterogeneous and there was no correlation between cortical layering patterns and aetiology. PMG was almost always associated with other brain malformations. INTERPRETATION: The inclusion of many fetal cases has allowed us to examine the early developmental stages of PMG. The study indicates the significance of surface signals responsible for human corticogenesis and the complex interaction between genetic and environmental factors leading to this common endpoint of cortical maldevelopment.


Subject(s)
Brain/pathology , Fetus/pathology , Polymicrogyria/pathology , Adolescent , Adult , Autopsy , Brain/cytology , Brain/growth & development , Child , Child, Preschool , Fetus/cytology , Humans , Infant , Infant, Newborn , Young Adult
7.
Hum Mol Genet ; 22(7): 1417-23, 2013 Apr 01.
Article in English | MEDLINE | ID: mdl-23297359

ABSTRACT

Kufs disease, an adult-onset neuronal ceroid lipofuscinosis, is challenging to diagnose and genetically heterogeneous. Mutations in CLN6 were recently identified in recessive Kufs disease presenting as progressive myoclonus epilepsy (Type A), whereas the molecular basis of cases presenting with dementia and motor features (Type B) is unknown. We performed genome-wide linkage mapping of two families with recessive Type B Kufs disease and identified a single region on chromosome 11 to which both families showed linkage. Exome sequencing of five samples from the two families identified homozygous and compound heterozygous missense mutations in CTSF within this linkage region. We subsequently sequenced CTSF in 22 unrelated individuals with suspected recessive Kufs disease, and identified an additional patient with compound heterozygous mutations. CTSF encodes cathepsin F, a lysosomal cysteine protease, dysfunction of which is a highly plausible candidate mechanism for a storage disorder like ceroid lipofuscinosis. In silico modeling suggested the missense mutations would alter protein structure and function. Moreover, re-examination of a previously published mouse knockout of Ctsf shows that it recapitulates the light and electron-microscopic pathological features of Kufs disease. Although CTSF mutations account for a minority of cases of type B Kufs, CTSF screening should be considered in cases with early-onset dementia and may avoid the need for invasive biopsies.


Subject(s)
Cathepsin F/genetics , Mutation, Missense , Neuronal Ceroid-Lipofuscinoses/genetics , Adult , Animals , Anterior Horn Cells/pathology , Case-Control Studies , Cathepsin F/metabolism , Chromosome Mapping , Consanguinity , DNA Mutational Analysis , Exome , Female , Genetic Association Studies , Humans , Lod Score , Mice , Mice, Knockout , Middle Aged , Models, Molecular , Neuronal Ceroid-Lipofuscinoses/enzymology , Neuronal Ceroid-Lipofuscinoses/pathology , Pedigree , Protein Structure, Secondary , Protein Structure, Tertiary , Sequence Analysis, RNA
8.
Am J Hum Genet ; 88(5): 566-73, 2011 May 13.
Article in English | MEDLINE | ID: mdl-21549341

ABSTRACT

The molecular basis of Kufs disease is unknown, whereas a series of genes accounting for most of the childhood-onset forms of neuronal ceroid lipofuscinosis (NCL) have been identified. Diagnosis of Kufs disease is difficult because the characteristic lipopigment is largely confined to neurons and can require a brain biopsy or autopsy for final diagnosis. We mapped four families with Kufs disease for whom there was good evidence of autosomal-recessive inheritance and found two peaks on chromosome 15. Three of the families were affected by Kufs type A disease and presented with progressive myoclonus epilepsy, and one was affected by type B (presenting with dementia and motor system dysfunction). Sequencing of a candidate gene in one peak shared by all four families identified no mutations, but sequencing of CLN6, found in the second peak and shared by only the three families affected by Kufs type A disease, revealed pathogenic mutations in all three families. We subsequently sequenced CLN6 in eight other families, three of which were affected by recessive Kufs type A disease. Mutations in both CLN6 alleles were found in the three type A cases and in one family affected by unclassified Kufs disease. Mutations in CLN6 are the major cause of recessive Kufs type A disease. The phenotypic differences between variant late-infantile NCL, previously found to be caused by CLN6, and Kufs type A disease are striking; there is a much later age at onset and lack of visual involvement in the latter. Sequencing of CLN6 will provide a simple diagnostic strategy in this disorder, in which definitive identification usually requires invasive biopsy.


Subject(s)
Membrane Proteins/genetics , Mutation , Neuronal Ceroid-Lipofuscinoses/etiology , Neuronal Ceroid-Lipofuscinoses/genetics , Adolescent , Adult , Age of Onset , Biopsy , Dementia/pathology , Exons , Female , Genetic Linkage , Genetic Testing/methods , Genotype , Heterozygote , Humans , Male , Middle Aged , Pedigree , Polymorphism, Single Nucleotide
9.
Neurosurg Focus ; 34(6): E6, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23724840

ABSTRACT

Hypothalamic hamartomas are uncommon but well-recognized developmental malformations that are classically associated with gelastic seizures and other refractory seizure types. The clinical course is often progressive and, in addition to the catastrophic epileptic syndrome, patients commonly exhibit debilitating cognitive, behavioral, and psychiatric disturbances. Over the past decade, investigators have gained considerable knowledge into the pathobiological and neurophysiological properties of these rare lesions. In this review, the authors examine the causes and molecular biology of hypothalamic hamartomas as well as the principal clinical features, neuroimaging findings, and electrophysiological characteristics. The diverse surgical modalities and strategies used to manage these difficult lesions are outlined in the second article of this 2-part review.


Subject(s)
Brain Waves/physiology , Epilepsy/etiology , Hamartoma , Hypothalamic Diseases , Electroencephalography , Hamartoma/complications , Hamartoma/diagnosis , Hamartoma/therapy , Humans , Hypothalamic Diseases/complications , Hypothalamic Diseases/diagnosis , Hypothalamic Diseases/therapy , Magnetoencephalography , Nerve Tissue Proteins/metabolism , Neuroimaging
10.
Neurosurg Focus ; 34(6): E7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23724841

ABSTRACT

Hypothalamic hamartomas are uncommon developmental heterotopic masses composed of an intermixed array of neurons, glia, and myelinated fibers closely associated with the mammillary bodies. Gelastic seizures, the hallmark feature of hypothalamic hamartomas, commonly present in early childhood. However, patients usually also display a disabling clinical syndrome, which may include various other types of refractory seizures with secondary generalization together with progressive cognitive, behavioral, and psychiatric dysfunction. The hamartoma itself has been unequivocally shown to be intrinsically epileptogenic. Over the past 2 decades there has been considerable effort to develop neurosurgical techniques to treat the epileptic syndrome effectively as well as to improve the neurocognitive and behavioral outcome.


Subject(s)
Hamartoma/complications , Hamartoma/therapy , Hypothalamic Diseases/complications , Hypothalamic Diseases/therapy , Neurosurgical Procedures/methods , Seizures/etiology , Treatment Outcome , Child, Preschool , Deep Brain Stimulation , Endoscopes , Humans , Magnetic Resonance Imaging , Male , Radiosurgery , Vagus Nerve Stimulation
11.
Neurogenetics ; 13(1): 31-47, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22218741

ABSTRACT

Interstitial deletions of 6q are associated with variable phenotypes, including growth retardation, dysmorphic features, upper limb malformations, and Prader-Willi (PW)-like features. Only a minority of cases in the literature have been characterized with high resolution techniques, making genotype-phenotype correlations difficult. We report 12 individuals with overlapping, 200-kb to 16.4-Mb interstitial deletions within 6q15q22.33 characterized by microarray-based comparative genomic hybridization to better correlate deletion regions with specific phenotypes. Four individuals have a PW-like phenotype, though only two have deletion of SIM1, the candidate gene for this feature. Therefore, other genes on 6q may contribute to this phenotype including multiple genes on 6q16 and our newly proposed candidate, the transcription cofactor gene VGLL2 on 6q22.2. Two individuals present with movement disorders as a major feature, and ataxia is present in a third. The 4.1-Mb 6q22.1q22.2 critical region for movement disorders includes the cerebellar-expressed candidate gene GOPC. Observed brain malformations include thick corpus callosum in two subjects, cerebellar vermal hypoplasia in two subjects, and cerebellar atrophy in one subject. Seven subjects' deletions overlap a ~250-kb cluster of four genes on 6q22.1 including MARCKS, HDAC2, and HS3ST5, which are involved in neural development. Two subjects have only this gene cluster deleted, and one deletion was apparently de novo, suggesting at least one of these genes plays an important role in development. Although the phenotypes associated with 6q deletions can vary, using overlapping deletions to delineate critical regions improves genotype-phenotype correlation for interstitial 6q deletions.


Subject(s)
Genetic Association Studies , Abnormalities, Multiple/genetics , Adult , Child , Child, Preschool , Chromosome Deletion , Chromosomes, Human, Pair 6/genetics , Computational Biology , Developmental Disabilities/genetics , Female , Humans , In Situ Hybridization, Fluorescence , Infant , Male , Microarray Analysis , Young Adult
12.
J Neurosci ; 30(28): 9612-20, 2010 Jul 14.
Article in English | MEDLINE | ID: mdl-20631190

ABSTRACT

Hyperekplexia is a rare, but potentially fatal, neuromotor disorder characterized by exaggerated startle reflexes and hypertonia in response to sudden, unexpected auditory or tactile stimuli. This disorder is primarily caused by inherited mutations in the genes encoding the glycine receptor (GlyR) alpha1 subunit (GLRA1) and the presynaptic glycine transporter GlyT2 (SLC6A5). In this study, systematic DNA sequencing of GLRA1 in 88 new unrelated human hyperekplexia patients revealed 19 sequence variants in 30 index cases, of which 21 cases were inherited in recessive or compound heterozygote modes. This indicates that recessive hyperekplexia is far more prevalent than previous estimates. From the 19 GLRA1 sequence variants, we have investigated the functional effects of 11 novel and 2 recurrent mutations. The expression levels and functional properties of these hyperekplexia mutants were analyzed using a high-content imaging system and patch-clamp electrophysiology. When expressed in HEK293 cells, either as homomeric alpha1 or heteromeric alpha1beta GlyRs, subcellular localization defects were the major mechanism underlying recessive mutations. However, mutants without trafficking defects typically showed alterations in the glycine sensitivity suggestive of disrupted receptor function. This study also reports the first hyperekplexia mutation associated with a GlyR leak conductance, suggesting tonic channel opening as a new mechanism in neuronal ligand-gated ion channels.


Subject(s)
Muscle Hypertonia/genetics , Receptors, Glycine/genetics , Reflex, Abnormal/genetics , Reflex, Startle/genetics , Cell Line , Female , Genetic Variation , Humans , Male , Mutation/genetics , Phenotype , Transfection
13.
Am J Hum Genet ; 82(3): 673-84, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18308289

ABSTRACT

Action myoclonus-renal failure syndrome (AMRF) is an autosomal-recessive disorder with the remarkable combination of focal glomerulosclerosis, frequently with glomerular collapse, and progressive myoclonus epilepsy associated with storage material in the brain. Here, we employed a novel combination of molecular strategies to find the responsible gene and show its effects in an animal model. Utilizing only three unrelated affected individuals and their relatives, we used homozygosity mapping with single-nucleotide polymorphism chips to localize AMRF. We then used microarray-expression analysis to prioritize candidates prior to sequencing. The disorder was mapped to 4q13-21, and microarray-expression analysis identified SCARB2/Limp2, which encodes a lysosomal-membrane protein, as the likely candidate. Mutations in SCARB2/Limp2 were found in all three families used for mapping and subsequently confirmed in two other unrelated AMRF families. The mutations were associated with lack of SCARB2 protein. Reanalysis of an existing Limp2 knockout mouse showed intracellular inclusions in cerebral and cerebellar cortex, and the kidneys showed subtle glomerular changes. This study highlights that recessive genes can be identified with a very small number of subjects. The ancestral lysosomal-membrane protein SCARB2/LIMP-2 is responsible for AMRF. The heterogeneous pathology in the kidney and brain suggests that SCARB2/Limp2 has pleiotropic effects that may be relevant to understanding the pathogenesis of other forms of glomerulosclerosis or collapse and myoclonic epilepsies.


Subject(s)
Chromosomes, Human, Pair 4/genetics , Genes, Recessive , Glomerulonephritis/genetics , Lysosomal Membrane Proteins/genetics , Myoclonic Epilepsies, Progressive/genetics , Receptors, Scavenger/genetics , Animals , Cerebellar Cortex/pathology , Chromosome Mapping , Gene Expression , Genetic Linkage , Genotype , Glomerulonephritis/pathology , Humans , Mice , Mice, Knockout , Myoclonic Epilepsies, Progressive/pathology , Oligonucleotide Array Sequence Analysis
14.
Brain ; 133(Pt 5): 1415-27, 2010 May.
Article in English | MEDLINE | ID: mdl-20403963

ABSTRACT

Polymicrogyria is one of the most common malformations of cortical development and is associated with a variety of clinical sequelae including epilepsy, intellectual disability, motor dysfunction and speech disturbance. It has heterogeneous clinical manifestations and imaging patterns, yet large cohort data defining the clinical and imaging spectrum and the relative frequencies of each subtype are lacking. The aims of this study were to determine the types and relative frequencies of different polymicrogyria patterns, define the spectrum of their clinical and imaging features and assess for clinical/imaging correlations. We studied the imaging features of 328 patients referred from six centres, with detailed clinical data available for 183 patients. The ascertainment base was wide, including referral from paediatricians, geneticists and neurologists. The main patterns of polymicrogyria were perisylvian (61%), generalized (13%), frontal (5%) and parasagittal parieto-occipital (3%), and in 11% there was associated periventricular grey matter heterotopia. Each of the above patterns was further divided into subtypes based on distinguishing imaging characteristics. The remaining 7% were comprised of a number of rare patterns, many not described previously. The most common clinical sequelae were epileptic seizures (78%), global developmental delay (70%), spasticity (51%) and microcephaly (50%). Many patients presented with neurological or developmental abnormalities prior to the onset of epilepsy. Patients with more extensive patterns of polymicrogyria presented at an earlier age and with more severe sequelae than those with restricted or unilateral forms. The median age at presentation for the entire cohort was 4 months with 38% presenting in either the antenatal or neonatal periods. There were no significant differences between the prevalence of epilepsy for each polymicrogyria pattern, however patients with generalized and bilateral forms had a lower age at seizure onset. There was significant skewing towards males with a ratio of 3:2. This study expands our understanding of the spectrum of clinical and imaging features of polymicrogyria. Progression from describing imaging patterns to defining anatomoclinical syndromes will improve the accuracy of prognostic counselling and will aid identification of the aetiologies of polymicrogyria, including genetic causes.


Subject(s)
Magnetic Resonance Imaging , Malformations of Cortical Development/classification , Malformations of Cortical Development/diagnosis , Age of Onset , Child, Preschool , Cohort Studies , Developmental Disabilities/etiology , Epilepsy/epidemiology , Epilepsy/etiology , Female , Humans , Infant , Infant, Newborn , Male , Malformations of Cortical Development/complications , Malformations of Cortical Development/epidemiology , Microcephaly/etiology , Muscle Spasticity/etiology , Prevalence , Sex Distribution
15.
Can J Neurol Sci ; 38(6): 839-44, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22030420

ABSTRACT

Stories abound about the medical abuses that have come to define medicine and the "pseudo"-neurosciences in the Third Reich. Well known are the Nazi program of euthanasia and the neuroscientific publications that arose from it. Nevertheless, during this widespread perversion of medical practice and science, true medical heroics persisted, even in the concentration camps. In December 1942, inmates of Camp Vapniarka began experiencing painful lower extremity muscle cramps, spastic paraparesis, and urinary incontinence. In order to reduce the cost of feeding the 1200, mostly Jewish, inmates of Camp Vapniarka and surreptitiously hasten their deaths, the Nazi-affiliated Romanian officers of the camp had begun feeding them a diet high in Lathyrus sativus. L. sativus is the neurotoxin implicated in neurolathyrism, a degenerative disease of the upper motor neurons. Dr. Arthur Kessler, one of the camp's prisoners, eventually identified the source of the epidemic. Armed with this knowledge, the inmates collectively organized to halt its spread.


Subject(s)
Concentration Camps/history , Heroin/history , National Socialism/history , Neurosciences/history , Heroin/therapeutic use , History, 20th Century , Humans , Pain/drug therapy , Pain/history
16.
Epilepsy Behav ; 17(4): 569-70, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20236869

ABSTRACT

A woman known to have never fully controlled idiopathic generalized epilepsy presented at 47 years of age with a new onset of drop attacks. After clinical investigations, including prolonged video/EEG telemetry, tilt-table testing, and multiple sleep latency tests, the etiology of her drop attacks remained elusive. Subsequently we were able to demonstrate that her drop attacks may be provoked by her voluntary recollection of memories of past sexual abuse. This case study highlights the need to consider psychological factors when evaluating otherwise unexplained drop attacks. In addition, we propose a seizure-provoking technique that may be used both effectively and ethically in the diagnosis of psychogenic drop attacks as well as nonepileptic seizures.


Subject(s)
Epilepsy, Generalized/complications , Syncope/etiology , Syncope/psychology , Electroencephalography , Female , Humans , Middle Aged , Psychophysiologic Disorders/complications , Psychophysiologic Disorders/psychology , Syncope/therapy , Video Recording
17.
Eur J Hum Genet ; 28(6): 783-789, 2020 06.
Article in English | MEDLINE | ID: mdl-31919451

ABSTRACT

Adult-onset neuronal ceroid lipofuscinoses (ANCL, Kufs disease) are rare hereditary neuropsychiatric disorders characterized by intralysosomal accumulation of ceroid in tissues. The ceroid accumulation primarily affects the brain, leading to neuronal loss and progressive neurodegeneration. Although several causative genes have been identified (DNAJC5, CLN6, CTSF, GRN, CLN1, CLN5, ATP13A2), the genetic underpinnings of ANCL in some families remain unknown. Here we report one family with autosomal dominant (AD) Kufs disease caused by a 30 bp in-frame duplication in DNAJC5, encoding the cysteine-string protein alpha (CSPα). This variant leads to a duplication of the central core motif of the cysteine-string domain of CSPα and affects palmitoylation-dependent CSPα sorting in cultured neuronal cells similarly to two previously described CSPα variants, p.(Leu115Arg) and p.(Leu116del). Interestingly, the duplication was not detected initially by standard Sanger sequencing due to a preferential PCR amplification of the shorter wild-type allele and allelic dropout of the mutated DNAJC5 allele. It was also missed by subsequent whole-exome sequencing (WES). Its identification was facilitated by reanalysis of original WES data and modification of the PCR and Sanger sequencing protocols. Independently occurring variants in the genomic sequence of DNAJC5 encoding the cysteine-string domain of CSPα suggest that this region may be more prone to DNA replication errors and that insertions or duplications within this domain should be considered in unsolved ANCL cases.


Subject(s)
Gene Duplication , HSP40 Heat-Shock Proteins/genetics , Membrane Proteins/genetics , Neuronal Ceroid-Lipofuscinoses/genetics , Adult , Animals , Cell Line , False Negative Reactions , Female , Genetic Testing/standards , HSP40 Heat-Shock Proteins/metabolism , Humans , Male , Membrane Proteins/metabolism , Mice , Middle Aged , Neuronal Ceroid-Lipofuscinoses/pathology , Neurons/metabolism , Protein Processing, Post-Translational , Protein Transport , Whole Genome Sequencing/standards
18.
Epilepsia ; 50(5): 1256-61, 2009 May.
Article in English | MEDLINE | ID: mdl-19175392

ABSTRACT

Epilepsy prevalence in the developing world is many fold that found in developed countries. For individuals whose conditions failed to respond to pharmacotherapy, surgery is the only opportunity for cure. In Uganda, we developed a center for treatment of intractable temporal lobe epilepsy (iTLE) that functions within the technologic and expertise constraints of a severely low resource area. Our model relies on partnership with epilepsy professionals and training of local staff. Patients were prescreened at regional clinics for iTLE. Individuals meeting inclusion criteria were referred to the treating Ugandan hospital (CURE Children's' Hospital of Uganda, CCHU) for video-EEG (electroencephalography), computed tomography (CT) imaging, and neuropsychological evaluation. Data were transferred to epilepsy experts for analysis and treatment recommendations. Ten patients were diagnosed with iTLE and surgically treated at CCHU. Six (60%) were seizure free, and there was no neurologic morbidity or mortality. Our model for surgical treatment of pharmacoresistant TLE has functioned successfully in a true developing world low resource setting.


Subject(s)
Epilepsy, Temporal Lobe/surgery , Neurosurgical Procedures/methods , Adolescent , Electroencephalography/methods , Epilepsy, Temporal Lobe/diagnosis , Epilepsy, Temporal Lobe/epidemiology , Female , Humans , Male , Neuropsychological Tests , Pilot Projects , Tomography, X-Ray Computed , Uganda/epidemiology , Young Adult
19.
J Neurosurg ; 110(2): 332-42, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19245287

ABSTRACT

OBJECT: The authors report long-term follow-up seizure outcome in patients who underwent corpus callosotomy during the period 1981-2001 at the Montreal Neurological Institute. METHODS: The records of 95 patients with a minimum follow-up of 5 years (mean 17.2 years) were retrospectively evaluated with respect to seizure, medication outcomes, and prognostic factors on seizure outcome. RESULTS: All patients had more than one type of seizure, most frequently drop attacks and generalized tonic-clonic seizures. The most disabling seizure type was drop attacks, followed by generalized tonic-clonic seizures. Improvement was noted in several seizure types and was most likely for generalized tonic-clonic seizures (77.3%) and drop attacks (77.2%). Simple partial, generalized tonic, and myoclonic seizures also benefited from anterior callosotomy. The extent of the callosal section was correlated with favorable seizure outcome. The complications were mild and transient and no death was seen. CONCLUSIONS: This study confirms that anterior callosotomy is an effective treatment in intractable generalized seizures that are not amenable to focal resection. When considering this procedure, the treating physician must thoroughly assess the expected benefits, limitations, likelihood of residual seizures, and the risks, and explain them to the patient, his or her family, and other caregivers.


Subject(s)
Corpus Callosum/surgery , Epilepsies, Myoclonic/surgery , Epilepsies, Partial/surgery , Epilepsy, Generalized/surgery , Epilepsy, Tonic-Clonic/surgery , Syncope/surgery , Adolescent , Adult , Anticonvulsants/therapeutic use , Cerebral Cortex/physiopathology , Cerebral Cortex/surgery , Child , Child, Preschool , Corpus Callosum/physiopathology , Electroencephalography , Epilepsies, Myoclonic/physiopathology , Epilepsies, Partial/diagnosis , Epilepsies, Partial/physiopathology , Epilepsy, Generalized/physiopathology , Epilepsy, Tonic-Clonic/diagnosis , Epilepsy, Tonic-Clonic/physiopathology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Neurologic Examination , Neuropsychological Tests , Postoperative Complications/diagnosis , Recurrence , Retrospective Studies , Syncope/diagnosis , Syncope/physiopathology , Tomography, X-Ray Computed , Video Recording , Young Adult
20.
Brain ; 131(Pt 12): 3246-55, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18812443

ABSTRACT

Focal cortical dysplasia (FCD) is often characterized by minor structural changes that may go unrecognized by standard radiological analysis. Visual assessment of morphological characteristics of FCD and sulci harbouring them is difficult due to the complexity of brain convolutions. Our purpose was to elucidate and quantify the spatial relationship between FCD lesions and brain sulci using automated sulcal extraction and morphometry. We studied 43 consecutive FCD patients using high-resolution MRI. Lesions were classified into small and large using qualitative (detection on initial clinical assessment of conventional MRI) and quantitative (volume) criteria. Sulci were identified and labelled automatically using an algorithm based on a congregation of neural networks. Segmented FCD lesions and sulci were then simultaneously visualized in 3D. We measured mean and maximum depth of sulci related to each FCD and of the corresponding sulci in 21 healthy controls. In addition, we calculated sulcal depth within the FCD neighbourhood. Twenty-one (21/43 = 49%) patients had small FCD lesions (volume range: 128-3093 mm(3)). Among them, 17 (81%) had been overlooked during initial radiological evaluation and were subsequently identified using image processing. Eighteen (18/21 = 86%) small FCD lesions were located at the bottom of a sulcus. Two others were related to the walls of two sulci and one was located at the crown of a gyrus. Mean and maximum depth of sulci related to the FCD was higher than that of the corresponding sulci in controls (P < 0.008). Sulcal depth within lesional neighbourhood had larger mean depth than that of the entire sulcus (P < 0.0002). Evidence that small FCD lesions are preferentially located at the bottom of an abnormally deep sulcus may be used to direct the search for developmental abnormalities, particularly in patients in whom large-scale MRI features are only mildly abnormal or absent.


Subject(s)
Malformations of Cortical Development/pathology , Adolescent , Adult , Brain Mapping/methods , Epilepsies, Partial/etiology , Female , Humans , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Male , Malformations of Cortical Development/complications , Temporal Lobe/abnormalities , Temporal Lobe/pathology , Young Adult
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