S F Berkovic

University of Melbourne, Melbourne, Victoria, Australia

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Publications (280)2046.8 Total impact

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    ABSTRACT: BACKGROUND: Although there is increasing recognition of the role of somatic mutations in genetic disorders, the prevalence of somatic mutations in neurodevelopmental disease and the optimal techniques to detect somatic mosaicism have not been systematically evaluated. METHODS: Using a customized panel of known and candidate genes associated with brain malformations, we applied targeted high-coverage sequencing (depth, ≥200×) to leukocyte-derived DNA samples from 158 persons with brain malformations, including the double-cortex syndrome (subcortical band heterotopia, 30 persons), polymicrogyria with megalencephaly (20), periventricular nodular heterotopia (61), and pachygyria (47). We validated candidate mutations with the use of Sanger sequencing and, for variants present at unequal read depths, subcloning followed by colony sequencing. RESULTS: Validated, causal mutations were found in 27 persons (17%; range, 10 to 30% for each phenotype). Mutations were somatic in 8 of the 27 (30%), predominantly in persons with the double-cortex syndrome (in whom we found mutations in DCX and LIS1), persons with periventricular nodular heterotopia (FLNA), and persons with pachygyria (TUBB2B). Of the somatic mutations we detected, 5 (63%) were undetectable with the use of traditional Sanger sequencing but were validated through subcloning and subsequent sequencing of the subcloned DNA. We found potentially causal mutations in the candidate genes DYNC1H1, KIF5C, and other kinesin genes in persons with pachygyria. CONCLUSIONS: Targeted sequencing was found to be useful for detecting somatic mutations in patients with brain malformations. High-coverage sequencing panels provide an important complement to whole-exome and whole-genome sequencing in the evaluation of somatic mutations in neuropsychiatric disease. (Funded by the National Institute of Neurological Disorders and Stroke and others.).
    New England Journal of Medicine 08/2014; 371(8):733-43. · 54.42 Impact Factor
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    ABSTRACT: We present the analysis of a prospective multicentre study to investigate genetic effects on prognosis of newly treated epilepsy. Patients with a new clinical diagnosis of epilepsy requiring medication were recruited and followed up prospectively. Clinical outcome was defined as freedom from seizures for a minimum of 12 months in accordance with the consensus statement from the International League Against Epilepsy (ILAE). Genetic effects on remission of seizures after starting treatment were analysed with and without adjustment for significant clinical prognostic factors, and the results from each cohort were combined using a fixed effects meta-analysis. After quality control, we analysed 889 newly treated epilepsy patients using 472,450 genotyped and 6.9 x 10(6) imputed single nucleotide polymorphisms. Suggestive evidence for association (defined as Pmeta<5.0 x 10(-7)) with remission of seizures after starting treatment was observed at three loci: 6p12.2 (rs492146, Pmeta=2.1 x 10(-7), OR[G]=0.57), 9p23 (rs72700966, Pmeta=3.1 x 10(-7), OR[C]=2.70) and 15q13.2 (rs143536437, Pmeta=3.2 x 10(-7), OR[C]=1.92). Genes of biological interest at these loci include PTPRD and ARHGAP11B (encoding functions implicated in neuronal development) and GSTA4 (a phase II biotransformation enzyme). Pathway analysis using two independent methods implicated a number of pathways in prognosis of epilepsy including KEGG categories 'calcium signaling pathway' and 'phosphatidylinositol signaling pathway'. Through a series of power curves, we conclude it is unlikely any single common variant explains >4.4% of the variation in outcome of newly treated epilepsy.
    Human Molecular Genetics 08/2013; · 7.69 Impact Factor
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    ABSTRACT: Background/Aims: Renin processing and storage is believed to occur in lysosome-like structures in the afferent arteriole. SCARB2/Limp-2 is a transmembrane lysosomal protein responsible for the intracellular trafficking of β-glucocerebrosidase. This study aimed to confirm the expression of SCARB2/Limp-2 in renin secretory granules, and explore its role in renin processing and secretion. Methods: Co-localisation studies of (pro)renin with lysosomal membrane proteins, SCARB2/Limp-2, LAMP-1 and LAMP-2, were performed in mouse and human kidney sections. Intrarenal expression and secretion of (pro)renin in wild-type (WT) and Limp-2(-/-) mice were compared with and without stimulation. Results: SCARB2/Limp-2, LAMP-1 and LAMP-2 co-localised with (pro)- renin in mouse and human kidney. Plasma renin concentration was increased in Limp-2(-/-) mice when compared to WT littermates. No change in (pro)renin expression, however, was observed in Limp-2(-/-) mouse kidney cortex by immunofluorescence microscopy, Western blotting, quantitative RT-PCR or the ultrastructural appearance of renin secretory granules. Acute stimulation of renin release by isoprenaline or hydralazine was similar in WT and Limp-2(-/-) mice. Following chronic salt restriction, however, immunofluorescence microscopy showed less (pro)renin expressed in Limp-2(-/-) compared with WT mouse kidneys, and there was significantly less prorenin but not renin by Western blotting in Limp-2(-/-) mouse kidney cortex, despite no difference in circulating renin levels. Conclusion: Renin secretory granules possess integral lysosomal proteins, confirming that they are indeed modified lysosomes. Limp-2 deficiency leads to a minor increase in circulating renin. Limp-2, however, is not required for acute or chronic stimulation of renin release.
    Nephron Experimental Nephrology 04/2013; 122(3-4):103-113. · 2.01 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE:Bilateral posterior PNH is a distinctive complex malformation with imaging features distinguishing it from classic bilateral PNH associated with FLNA mutations. The purpose of this study was to define the imaging features of posterior bilateral periventricular nodular heterotopia and to determine whether associated brain malformations suggest specific subcategories.MATERIALS AND METHODS:We identified a cohort of 50 patients (31 females; mean age, 13 years) with bilateral posterior PNH and systematically reviewed and documented associated MR imaging abnormalities. Patients were negative for mutations of FLNA.RESULTS:Nodules were often noncontiguous (n = 28) and asymmetric (n = 31). All except 1 patient showed associated developmental brain abnormalities involving a spectrum of posterior structures. A range of posterior fossa abnormalities affected the cerebellum, including cerebellar malformations and posterior fossa cysts (n = 38). Corpus callosum abnormalities (n = 40) ranged from mild dysplasia to agenesis. Posterior white matter volume was decreased (n = 22), and colpocephaly was frequent (n = 26). Most (n = 40) had associated cortical abnormalities ranging from minor to major (polymicrogyria), typically located in the cortex overlying the PNH. Abnormal Sylvian fissure morphology was common (n = 27), and hippocampal abnormalities were frequent (n = 37). Four family cases were identified-2 with concordant malformation patterns and 2 with discordant malformation patterns.CONCLUSIONS:The associations of bilateral posterior PNH encompass a range of abnormalities involving brain structures inferior to the Sylvian fissures. We were unable to identify specific subgroups and therefore conceptualize bilateral posterior PNH as a continuum of infrasylvian malformations involving the posterior cerebral and hindbrain structures.
    American Journal of Neuroradiology 01/2013; · 3.17 Impact Factor
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    ABSTRACT: Epilepsy comprises several syndromes, amongst the most common being mesial temporal lobe epilepsy with hippocampal sclerosis. Seizures in mesial temporal lobe epilepsy with hippocampal sclerosis are typically drug-resistant, and mesial temporal lobe epilepsy with hippocampal sclerosis is frequently associated with important co-morbidities, mandating the search for better understanding and treatment. The cause of mesial temporal lobe epilepsy with hippocampal sclerosis is unknown, but there is an association with childhood febrile seizures. Several rarer epilepsies featuring febrile seizures are caused by mutations in SCN1A, which encodes a brain-expressed sodium channel subunit targeted by many anti-epileptic drugs. We undertook a genome-wide association study in 1018 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 7552 control subjects, with validation in an independent sample set comprising 959 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 3591 control subjects. To dissect out variants related to a history of febrile seizures, we tested cases with mesial temporal lobe epilepsy with hippocampal sclerosis with (overall n = 757) and without (overall n = 803) a history of febrile seizures. Meta-analysis revealed a genome-wide significant association for mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures at the sodium channel gene cluster on chromosome 2q24.3 [rs7587026, within an intron of the SCN1A gene, P = 3.36 x 10-9, odds ratio (A) = 1.42, 95% confidence interval: 1.26-1.59]. In a cohort of 172 individuals with febrile seizures, who did not develop epilepsy during prospective follow-up to age 13 years, and 6456 controls, no association was found for rs7587026 and febrile seizures. These findings suggest SCN1A involvement in a common epilepsy syndrome, give new direction to biological understanding of mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures, and open avenues for investigation of prognostic factors and possible prevention of epilepsy in some children with febrile seizures.
    Brain 01/2013; · 10.23 Impact Factor
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    ABSTRACT: Studies of absence seizures (AS) using EEG with fMRI (EEG-fMRI) show a consistent network with prominent thalamic activation and a variety of cortical changes. Despite evidence suggesting a role of frontal cortex in seizure generation, group studies have not detected consistent AS-related changes in this region. We hypothesized that only a subgroup may show frontal cortical activation. We studied 13 subjects with AS during EEG-fMRI to classify the different individual patterns of frontal cortical activation associated with AS. Based upon visual inspection of surface-rendered activation maps we identified 2 subgroups that could be distinguished by the activation in the dorsolateral prefrontal cortex (DLPFC). One group of patients (n = 7) showed a primarily positive signal change (DLPFC-POS), whereas the other group (n = 6) showed a primarily negative signal change (DLFPC-NEG). When the DLPFC-POS group was compared to the DLPFC-NEG group, time-course analysis revealed a larger positive blood oxygenation level-dependent deflection following onset of the AS in cortical and subcortical areas beyond the DLPFC. This suggests a basic biological difference between these groups. These observations suggest that there may be at least 2 mechanisms underpinning AS in individuals with absence epilepsy. This may have phenotypic and genetic implications for understanding epilepsy syndromes.
    Neurology 04/2012; 78(15):1157-65. · 8.30 Impact Factor
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    ABSTRACT: Benign neonatal sleep myoclonus is an uncommon, nonepileptic disorder characterized by myoclonic jerks appearing in the neonatal period that occur predominantly during sleep. Although self-limiting, the disorder is frequently confused with epileptic neonatal seizures. A few familial cases have been reported; however the genetics has not been studied. We ascertained 3 families with 2 or more affected individuals and analyzed the pedigrees. We used microsatellite markers to determine if the disorder was possibly linked to KCNQ2 or KCNQ3, the 2 genes that cause most cases of benign familial neonatal seizures, a disorder that it could be easily confused with. The 3 pedigrees, including one with 4 affected individuals, were suggestive of autosomal dominant inheritance. The loci for KCNQ2 and KCNQ3 were excluded in the 2 larger families. We conclude that benign neonatal sleep myoclonus can show autosomal dominant inheritance and is not allelic with benign familial neonatal seizures.
    Journal of child neurology 03/2012; 27(10):1260-3. · 1.59 Impact Factor
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    ABSTRACT: To determine the genetic etiology of the severe early infantile onset syndrome of malignant migrating partial seizures of infancy (MPSI). Fifteen unrelated children with MPSI were screened for mutations in genes associated with infantile epileptic encephalopathies: SCN1A, CDKL5, STXBP1, PCDH19, and POLG. Microarray studies were performed to identify copy number variations. One patient had a de novo SCN1A missense mutation p.R862G that affects the voltage sensor segment of SCN1A. A second patient had a de novo 11.06 Mb deletion of chromosome 2q24.2q31.1 encompassing more than 40 genes that included SCN1A. Screening of CDKL5 (13/15 patients), STXBP1 (13/15), PCDH19 (9/11 females), and the 3 common European mutations of POLG (11/15) was negative. Pathogenic copy number variations were not detected in 11/12 cases. Epilepsies associated with SCN1A mutations range in severity from febrile seizures to severe epileptic encephalopathies including Dravet syndrome and severe infantile multifocal epilepsy. MPSI is now the most severe SCN1A phenotype described to date. While not a common cause of MPSI, SCN1A screening should now be considered in patients with this devastating epileptic encephalopathy.
    Neurology 07/2011; 77(4):380-3. · 8.30 Impact Factor
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    ABSTRACT: Deficiency of the intrinsic lysosomal protein human scavenger receptor class B, member 2 (SCARB2; Limp-2 in mice) causes collapsing focal and segmental glomerular sclerosis (FSGS) and myoclonic epilepsy in humans, but patients with no apparent kidney damage have recently been described. We now demonstrate that these patients can develop tubular proteinuria. To determine the mechanism, mice deficient in Limp-2, the murine homolog of SCARB2, were studied. Most low-molecular-weight proteins filtered by the glomerulus are removed in the proximal convoluted tubule (PCT) by megalin/cubilin-dependent receptor-mediated endocytosis. Expression of megalin and cubilin was unchanged in Limp-2(-/-) mice, however, and the initial uptake of injected Alexa Fluor 555-conjugated bovine serum albumin (Alexa-BSA) was similar to wild-type mice, indicating that megalin/cubilin-dependent, receptor-mediated endocytosis was unaffected. There was a defect in proteolysis of reabsorbed proteins in the Limp-2(-/-) mice, demonstrated by the persistence of Alexa-BSA in the PCT compared with controls. This was associated with the failure of the lysosomal protease cathepsin B to colocalize with Alexa-BSA and endogenous retinol-binding protein in kidneys from Limp-2(-/-) mice. The data suggest that tubular proteinuria in Limp-2(-/-) mice is due to failure of endosomes containing reabsorbed proteins to fuse with lysosomes in the proximal tubule of the kidney. Failure of proteolysis is a novel mechanism for tubular proteinuria.
    AJP Renal Physiology 03/2011; 300(6):F1437-47. · 4.42 Impact Factor
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  • Clinical Neurophysiology - CLIN NEUROPHYSIOL. 01/2011; 122.
  • Epilepsia. 01/2011;
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    ABSTRACT: We used EEG-fMRI to study epileptiform activity in a cohort of untreated children with typical absence seizures (AS). Our aim was to identify cortical and subcortical regions involved in spike and wave events and to explore the timing of activity in these regions. Eleven children with AS confirmed on video-EEG underwent EEG-fMRI. An event-related analysis of epileptiform activity was performed. Regions of interest (ROIs), identified in the event-related analysis, were used to study the time course of the blood oxygen level-dependent (BOLD) signal prior to and immediately following events of interest in these ROIs. Group analysis confirmed positive BOLD in the thalamus and negative BOLD in the lateral and mesial parietal lobe, caudate nuclei, and additionally the brainstem reticular formation. The event-related time course differed between the thalamus, the parietal cortex, and the pons and caudate nuclei. In the subcortical structures, BOLD signal change occurred at, or immediately after, electrographic onset. Importantly, in the parietal cortex, but not in other cortical regions, there was a subtle BOLD signal increase for 10 seconds prior to the onset of epileptiform activity. In children with typical AS, we have confirmed a core network of structures involved in generalized epileptiform activity that includes the reticular structures of the brainstem. Furthermore, we have identified changes in parietal BOLD signal which precede the onset of epileptiform activity, suggesting the parietal cortex has a role in the initiation of epileptiform activity.
    Neurology 09/2010; 75(10):904-11. · 8.30 Impact Factor
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    ABSTRACT: Heterozygous mutations in STXBP1, encoding the syntaxin binding protein 1, have recently been identified in Ohtahara syndrome, an epileptic encephalopathy with very early onset. In order to explore the phenotypic spectrum associated with STXBP1 mutations, we analyzed a cohort of patients with unexplained early-onset epileptic encephalopathies. We collected and clinically characterized 106 patients with early-onset epileptic encephalopathies. Mutation analysis of the STXBP1 gene was done using sequence analysis of the exon and intron-exon boundaries and multiplex amplification quantification to detect copy number variations. We identified 4 truncating mutations and 2 microdeletions partially affecting STXBP1 in 6 of the 106 patients. All mutations are predicted to abolish STXBP1 function and 5 mutations were proven to occur de novo. None of the mutation-carrying patients had Ohtahara syndrome. One patient was diagnosed with West syndrome at disease onset, while the initial phenotype of 5 further patients did not fit into a specific recognized epilepsy syndrome. Three of these patients later evolved to West syndrome. All patients had severe to profound mental retardation, and ataxia or dyskinetic movements were present in 5 patients. This study shows that mutations in STXBP1 are not limited to patients with Ohtahara syndrome, but are also present in 10% (5/49) of patients with an early-onset epileptic encephalopathy that does not fit into either Ohtahara or West syndrome and rarely in typical West syndrome. STXBP1 mutational analysis should be considered in the diagnostic evaluation of this challenging group of patients.
    Neurology 09/2010; 75(13):1159-65. · 8.30 Impact Factor
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    ABSTRACT: Familial glucose transporter type 1 (GLUT1) deficiency due to autosomal dominant inheritance of SLC2A1 mutations is associated with paroxysmal exertional dyskinesia; epilepsy and intellectual disability occur in some family members. We recently demonstrated that GLUT1 deficiency occurs in over 10% of patients with early-onset absence epilepsy. This family study analyses the phenotypes in 2 kindreds segregating SLC2A1 mutations identified through probands with early-onset absence epilepsy. One comprised 9 individuals with mutations over 3 generations; the other had 6 individuals over 2 generations. Of 15 subjects with SLC2A1 mutations, epilepsy occurred in 12. Absence seizures were the most prevalent seizure type (10/12), with onset from 3 to 34 years of age. Epilepsy phenotypes varied widely, including idiopathic generalized epilepsies (IGE) with absence (8/12), myoclonic-astatic epilepsy (2/12), and focal epilepsy (2/12). Paroxysmal exertional dyskinesia occurred in 7, and was subtle and universally undiagnosed prior to molecular diagnosis. There were 2 unaffected mutation carriers. GLUT1 deficiency is an important monogenic cause of absence epilepsies with onset from early childhood to adult life. Individual cases may be phenotypically indistinguishable from common forms of IGE. Although subtle paroxysmal exertional dyskinesia is a helpful diagnostic clue, it is far from universal. The phenotypic spectrum of GLUT1 deficiency is considerably greater than previously recognized. Diagnosis of GLUT1 deficiency has important treatment and genetic counseling implications.
    Neurology 08/2010; 75(5):432-40. · 8.30 Impact Factor
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    ABSTRACT: Photoparoxysmal response (PPR) is considered to be a risk factor for idiopathic generalised epilepsy (IGE) and it has a strong genetic basis. Two genome-wide linkage studies have been published before and they identified loci for PPR at 6p21, 7q32, 13q13, 13q31 and 16p13. Here we combine these studies, augmented with additional families, in a mega-analysis of 100 families. Non-parametric linkage analysis identified three suggestive peaks for photosensitivity, two of which are novel (5q35.3 and 8q21.13) and one has been found before (16p13.3). We found no evidence for linkage at four previously detected loci (6p21, 7q32, 13q13 and 13q31). Our results suggest that the different family data sets are not linked to a shared locus. Detailed analysis showed that the peak at 16p13 was mainly supported by a single subset of families, while the peaks at 5q35 and 8q21 had weak support from multiple subsets. Family studies clearly support the role of PPR as a risk factor for IGE. This mega-analysis shows that distinct loci seem to be linked to subsets of PPR-positive families that may differ in subtle clinical phenotypes or geographic origin. Further linkage studies of PPR should therefore include in-depth phenotyping to make appropriate subsets and increase genetic homogeneity.
    Epilepsy research 02/2010; 89(2-3):286-94. · 2.48 Impact Factor
  • Epilepsia. 01/2010; 51:23-23.
  • Clinical Neurophysiology - CLIN NEUROPHYSIOL. 01/2010; 121.

Publication Stats

13k Citations
2,046.80 Total Impact Points

Institutions

  • 1992–2013
    • University of Melbourne
      • • Department of Medicine
      • • Australian Venom Research Institute
      Melbourne, Victoria, Australia
  • 2012
    • Tel Aviv University
      • Faculty of Medicine
      Tel Aviv, Tel Aviv, Israel
  • 2008
    • University of Queensland 
      • Queensland Brain Institute
      Brisbane, Queensland, Australia
  • 1993–2007
    • The Royal Children's Hospital
      • • Department of Neurology
      • • Department of Neurosurgery
      Melbourne, Victoria, Australia
    • Mayo Foundation for Medical Education and Research
      • Department of Neurology
      Scottsdale, AZ, United States
  • 2005
    • Schneider Children's Medical Center of Israel
      Petah Tikva, Central District, Israel
  • 1998–2004
    • Victoria University Melbourne
      Melbourne, Victoria, Australia
  • 1987–2004
    • McGill University
      • • Department of Neurology and Neurosurgery
      • • Department of Neuropathology
      • • Centre for Research in Neuroscience
      Montréal, Quebec, Canada
  • 1996–2003
    • Beth Israel Deaconess Medical Center
      • Department of Neurology
      Boston, MA, United States
  • 2002
    • Sendai National College of Technology
      Sendai, Kagoshima, Japan
    • University of Adelaide
      Tarndarnya, South Australia, Australia
  • 2001
    • Tel Aviv Sourasky Medical Center
      • Department of Neurology
      Tel Aviv, Tel Aviv, Israel
  • 2000
    • Boston Children's Hospital
      • Department of Radiology
      Boston, MA, United States
  • 1997–2000
    • Victorian Institute of Forensic Medicine
      Victoria Point, Queensland, Australia
  • 1994–1999
    • Monash University (Australia)
      • • Department of Forensic Medicine
      • • School of Psychology and Psychiatry
      Melbourne, Victoria, Australia
    • Kuopio University Hospital
      Kuopio, Eastern Finland Province, Finland
  • 1983–1998
    • Austin Health
      • Department of Neurology
      Melbourne, Victoria, Australia
  • 1993–1997
    • Royal Melbourne Hospital
      Melbourne, Victoria, Australia
  • 1995
    • University of Bonn
      • Institute of Human Genetics
      Bonn, North Rhine-Westphalia, Germany
    • Yale University
      • Department of Neurology
      New Haven, CT, United States