Publications by authors named "Karl M Klein"

Objective: Somatic variants causing epilepsy are challenging to detect, as they are only present in a subset of brain cells (e.g., mosaic), resulting in low variant allele frequencies.

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Objective: Recent studies have identified brain somatic variants as a cause of focal epilepsy. These studies relied on resected tissue from epilepsy surgery, which is not available in most patients. The use of trace tissue adherent to depth electrodes used for stereo electroencephalography (EEG) has been proposed as an alternative but is hampered by the low cell quality and contamination by nonbrain cells.

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Hypothalamic hamartoma (HH) is a rare benign developmental brain lesion commonly associated with a well characterized epilepsy phenotype. Most individuals with HH are non-syndromic without additional developmental anomalies nor a family history of disease. Nonetheless, HH is a feature of Pallister-Hall (PHS) and Oro-Facial-Digital Type VI (OFD VI) syndromes, both characterized by additional developmental anomalies.

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Objective: This study was undertaken to develop a multimodal machine learning (ML) approach for predicting incident depression in adults with epilepsy.

Methods: We randomly selected 200 patients from the Calgary Comprehensive Epilepsy Program registry and linked their registry-based clinical data to their first-available clinical electroencephalogram (EEG) and magnetic resonance imaging (MRI) study. We excluded patients with a clinical or Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)-based diagnosis of major depression at baseline.

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Importance: Both epilepsy and enzyme-inducing antiseizure medications (eiASMs) having varying reports of an association with increased risks for osteoporosis.

Objective: To quantify and model the independent hazards for osteoporosis associated with incident epilepsy and eiASMS and non-eiASMs.

Design, Setting, And Participants: This open cohort study covered the years 1998 to 2019, with a median (IQR) follow-up of 5 (1.

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Purpose: Hypothalamic hamartoma (HH) can be syndromic (eg, Pallister-Hall syndrome [PHS], HH, and mesoaxial polydactyly) or nonsyndromic. Most PHS cases have germline variants in , but a minority remain unresolved. Some nonsyndromic HH cases have mosaic variants in the brain.

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Article Synopsis
  • Familial adult myoclonus epilepsy (FAME) is a type of epilepsy caused by genetic factors, and scientists have been trying to understand it for a long time.
  • Recent research has found specific gene changes that are linked to FAME in different parts of the world.
  • The study of these genetic changes can help experts learn more about the disease and eventually create better ways to diagnose and treat it.
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Objective: The phenotypic and genotypic spectrum of adult patients with epilepsy and intellectual disability (ID) is less clear than in children. We investigated an adult patient cohort to further elucidate this and inform the genetic testing approach.

Methods: Fifty-two adult patients (30 male, 22 female) with epilepsy, at least mild ID and no known genetic or acquired cause were included and phenotyped.

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Identifying genetic risk factors for highly heterogeneous disorders like epilepsy remains challenging. Here, we present the largest whole-exome sequencing study of epilepsy to date, with >54,000 human exomes, comprising 20,979 deeply phenotyped patients from multiple genetic ancestry groups with diverse epilepsy subtypes and 33,444 controls, to investigate rare variants that confer disease risk. These analyses implicate seven individual genes, three gene sets, and four copy number variants at exome-wide significance.

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Familial adult myoclonic epilepsy (FAME) is an adult-onset neurological disease characterized by cortical tremor, myoclonus, and seizures due to a pentanucleotide repeat expansion: a combination of pathogenic TTTCA expansion associated with a TTTTA repeat in introns of six different genes. Repeat-primed PCR (RP-PCR) is an inexpensive test for expansions at known loci. The analysis of the SAMD12 locus revealed that the repeats have different size, configuration, and composition.

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Article Synopsis
  • The study focuses on adults with STXBP1-related developmental and epileptic encephalopathy (STXBP1-DEE), examining seizure types, movement disorders, and functional independence.
  • It included 30 adult patients with severe epilepsy; 80% had treatment-resistant seizures, and most exhibited significant developmental impairment and behavioral challenges.
  • Video assessments revealed gait and movement disorders in patients, with varying levels of mobility and a high prevalence of severe intellectual disability and autistic features.
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Article Synopsis
  • The study focuses on Kv3.2, a potassium channel crucial for high-frequency brain firing and efficient action potential generation, examining its genetic variations linked to epilepsy.
  • Researchers analyzed clinical data and functional characteristics of Kv3.2 variants found in patients with different types of epilepsy, including cases like genetic generalized epilepsy and severe developmental epilepsy.
  • Results revealed that out of 18 identified variants, 10 were new and linked to severe epilepsy forms, leading to significant insights about Kv3.2's involvement in epilepsy and its role in regulating brain activity.
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Purpose: Pathogenic variants in GABRB3 have been associated with a spectrum of phenotypes from severe developmental disorders and epileptic encephalopathies to milder epilepsy syndromes and mild intellectual disability (ID). In this study, we analyzed a large cohort of individuals with GABRB3 variants to deepen the phenotypic understanding and investigate genotype-phenotype correlations.

Methods: Through an international collaboration, we analyzed electro-clinical data of unpublished individuals with variants in GABRB3, and we reviewed previously published cases.

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Objective: This study aimed to measure health-related quality of life (HRQOL) in children and adolescents with tuberous sclerosis complex (TSC) and quality of life (QOL) and depressive symptoms among caregivers.

Methods: Adequate metrics were used to assess HRQOL in children and adolescents with TSC (4-18 years, KINDL) as well as QOL (EQ-5D) and symptoms of depression (BDI-II) among caregivers. Predictors for reduced HRQOL and depressive symptoms were identified by variance analysis, ordinal regression, and bivariate correlation.

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Background And Objective: Pathogenic variants in KCNT1 have been associated with severe forms of epilepsy, typically sleep-related hypermotor epilepsy or epilepsy of infancy with migrating focal seizures. To show that pathogenic variants in KCNT1 can be associated with mild extra-frontal epilepsy, we report a KCNT1 family with a wide spectrum of phenotypes ranging from developmental and epileptic encephalopathy to mild focal epilepsy without cognitive regression and not consistent with sleep-related hypermotor epilepsy.

Methods: A large Canadian family of Caucasian descent including 9 affected family members was recruited.

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We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability).

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Background: The approval of everolimus (EVE) for the treatment of angiomyolipoma (2013), subependymal giant cell astrocytoma (2013) and drug-refractory epilepsy (2017) in patients with tuberous sclerosis complex (TSC) represents the first disease-modifying treatment option available for this rare and complex genetic disorder.

Objective: The objective of this study was to analyse the use, efficacy, tolerability and treatment retention of EVE in patients with TSC in Germany from the patient's perspective.

Methods: A structured cross-age survey was conducted at 26 specialised TSC centres in Germany and by the German TSC patient advocacy group between February and July 2019, enrolling children, adolescents and adult patients with TSC.

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Background: Tuberous sclerosis complex (TSC) is a monogenetic, multisystemic disease characterised by the formation of benign tumours that can affect almost all organs, caused by pathogenic variations in TSC1 or TSC2. In this multicentre study from Germany, we investigated the influence of sociodemographic, clinical, and therapeutic factors on quality of life (QoL) among individuals with TSC.

Methods: We assessed sociodemographic and clinical characteristics and QoL among adults with TSC throughout Germany using a validated, three-month, retrospective questionnaire.

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Background: Tuberous sclerosis complex (TSC), a multisystem genetic disorder, affects many organs and systems, characterized by benign growths. This German multicenter study estimated the disease-specific costs and cost-driving factors associated with various organ manifestations in TSC patients.

Methods: A validated, three-month, retrospective questionnaire was administered to assess the sociodemographic and clinical characteristics, organ manifestations, direct, indirect, out-of-pocket, and nursing care-level costs, completed by caregivers of patients with TSC throughout Germany.

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Background: Tuberous sclerosis complex (TSC) is a monogenetic, multisystem disorder characterized by benign growths due to TSC1 or TSC2 mutations. This German multicenter study estimated the costs and related cost drivers associated with organ manifestations in adults with TSC.

Methods: A validated, three-month, retrospective questionnaire assessed the sociodemographic and clinical characteristics, organ manifestations, direct, indirect, out-of-pocket (OOP), and nursing care-level costs among adult individuals with TSC throughout Germany from a societal perspective (costing year: 2019).

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Objective: The term 'precision medicine' describes a rational treatment strategy tailored to one person that reverses or modifies the disease pathophysiology. In epilepsy, single case and small cohort reports document nascent precision medicine strategies in specific genetic epilepsies. The aim of this multicentre observational study was to investigate the deeper complexity of precision medicine in epilepsy.

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Objective: To use clinically informed machine learning to derive prediction models for early and late premature death in epilepsy.

Methods: This was a population-based primary care observational cohort study. All patients meeting a case definition for incident epilepsy in the Health Improvement Network database for inclusive years 2000-2012 were included.

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Pharmacoresistance is a major burden in epilepsy treatment. We aimed to identify genetic biomarkers in response to specific antiepileptic drugs (AEDs) in genetic generalized epilepsies (GGE). We conducted a genome-wide association study (GWAS) of 3.

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Article Synopsis
  • The study focused on understanding how body positions change during generalized convulsive seizures (GCSs) and their relation to sudden unexpected death in epilepsy (SUDEP).
  • Among the 494 analyzed seizures, a significant number of patients shifted body positions, with a striking correlation between starting in a prone position and remaining prone during and after the seizure.
  • The findings suggest that epilepsy patients should be encouraged to sleep in non-prone positions (like supine or lateral) to potentially lower their risk of SUDEP.
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Purpose: Epilepsy surgery is an evidence-based treatment for drug-refractory focal epilepsy. We aimed to evaluate how well preoperative outcome estimates of epilepsy surgery in clinical practice correlated with postoperative outcome and to compare prediction by the clinical team with available scores (m-SFS, ESN).

Method: Retrospective cohort study including patients with drug-refractory focal epilepsy who underwent resective epilepsy surgery at Epilepsy Center Hessen, Marburg, between 1998-2016.

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