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The rapid detection of SARS-CoV-2 infections is essential for both diagnostic and prognostic reasons: However, the current gold standard for COVID-19 diagnosis, that is the rRT-PCR test, is affected by long turnaround time, potential shortage of reagents, high false-negative rates and high costs. Thus, Machine Learning (ML) based methods have recently attracted increasing interest, especially when applied to digital imaging (x-rays and CT scans). In this article, we review the literature on ML-based diagnostic and prognostic methods grounding on hematochemical parameters. In doing so, we address the gap in the existing literature, which has so far neglected the application of ML to laboratory medicine. We surveyed 20 research articles, extracted from the Scopus and PubMed indexes. These studies were characterized by a large heterogeneity, in terms of considered laboratory and clinical parameters, sample size, reference population, employed ML methods and validation procedures. Most studies were found to be affected by reporting and replicability issues: Among the surveyed studies, only three reported complete information regarding the analytic methods (units of measure, analyzing equipment), while nine studies reported no information at all. Furthermore, only six studies reported results on independent external validation. In light of these results, we discuss the importance of a tighter collaboration between data scientists and medicine laboratory professionals, so as to correctly characterize the relevant population, select the most appropriate statistical and analytical methods, ensure reproducibility, enable the correct interpretation of the results, and gain actual usefulness by applying ML methods in clinical practice.

In the article titled "Genetic testing in neurology exploiting next generation sequencing: state of art", published on pages 265-266, Issue 2, Volume 15 of Neural Regeneration Research (Di Resta and Ferrari, 2020), the reference "Di Resta C, Spiga I, Presi S, Merella S, Pipitone GB, Manitto MP, Querques G, Parodi MB, Ferrari M, Carrera P (2018) Integration of multigene panels for the diagnosis of hereditary retinal disorders using Next Generation Sequencing and bioinformatics approaches. EJIFCC 29:15-25." was cited inappropriately. The appropriate reference is "Di Resta C, Becchetti A (2010) Introduction to ion channels. Adv Exp Med Biol 674:9-21.

Developments in "-omics" are creating a paradigm shift in laboratory medicine leading to personalized medicine. This allows the increase in diagnostics and therapeutics focused on individuals rather than populations. In order to investigate whether laboratory medicine is ready to play a key role in the integration of personalized medicine in routine health care and set the state-of-the-art knowledge about personalized medicine and laboratory medicine in Europe, a questionnaire was constructed under the auspices of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) and the European Society of Pharmacogenomics and Personalised Therapy (ESPT). The answers of the participating laboratory medicine professionals indicate that they are aware that personalized medicine can represent a new and promising health model, and that laboratory medicine should play a key role in supporting the implementation of personalized medicine in the clinical setting. Participants think that the current organization of laboratory medicine needs additional/relevant implementations such as (i) new technological facilities in -omics; (ii) additional training for the current personnel focused on the new methodologies; (iii) incorporation in the laboratory of new competencies in data interpretation and counseling; and (iv) cooperation and collaboration among professionals of different disciplines to integrate information according to a personalized medicine approach. ispartof: Drug Metab Pers Ther vol:30 issue:2 pages:121-128 ispartof: location:Germany status: published

Developments in "omics" are creating a paradigm shift in Laboratory Medicine leading to Personalised Medicine. This allows the increasing in diagnostics and therapeutics focused on individuals rather than populations. In order to investigate whether Laboratory Medicine is able to implement new diagnostic tools and expertise and commands proper state-of-the-art knowledge about Personalized Medicine and Laboratory Medicine in Europe, the joint Working Group "Personalized Laboratory Medicine" of the EFLM and ESPT societies compiled and conducted the Questionnaire "Is Laboratory Medicine ready for the era of Personalized Medicine?". 48 laboratories from 18 European countries participated at this survey. The answers of the participating Laboratory Medicine professionals indicate that they are aware that Personalized Medicine can represent a new and promising health model. Whereas they are aware that Laboratory Medicine should play a key role to support the implementation of Personalized Medicine in the clinical settings, the participants of this survey think that the current organization of the Laboratory Medicine needs additional/relevant implementations such as: 1. New technological Facilities in "omics"; 2. Additional training for the current personnel focused on the new methodologies; 3. Incorporation in the Laboratory of new competencies in data interpretation and counselling; 4. Improving cooperation and collaboration between professionals of different disciplines to integrate information suitable for a Personalized Medicine approach. This survey suggest a strategic plan that should be considered by both health care providers and scientific societies of Laboratory Medicine. The implementation of Personalized Medicine should be first tested in a limited number of centers (Academic / Hospitals) possessing a wide range of competencies and facilities in "-omics" and in bioinformatics. These centers should then be supported to gain the missing technological facilities and appropriately trained for this aim.

In recent years, Next-Generation Sequencing (NGS) opened a new way for the study of pathogenic mechanisms and for molecular diagnosis of inherited disorders. In the present work, we focused our attention on the inherited retinal dystrophies (IRDs), a group of specific disorders of the retina, displaying a very high clinical and genetic heterogeneity, whose genetic diagnosis is not easily feasible. It represents a paradigmatic example for the integration of clinical and molecular examination toward precision medicine. In this paper, we discuss the use of targeted NGS resequencing of selected gene panels in a cohort of patients affected by IRDs. We tested the hypothesis to apply a selective approach based on a careful clinical examination. By this approach we reached a 66% overall detection rate for pathogenic variants, with a 52% diagnostic yield. Reduction of the efforts for validation and classification of variants is a clear advantage for the management of genetic testing in a clinical setting.

The investigation of genetic forms of juvenile neurodegeneration could shed light on the causative mechanisms of neuronal loss. Schinzel-Giedion syndrome (SGS) is a fatal developmental syndrome caused by mutations in the SETBP1 gene, inducing the accumulation of its protein product. SGS features multi-organ involvement with severe intellectual and physical deficits due, at least in part, to early neurodegeneration. Here we introduce a human SGS model that displays disease-relevant phenotypes. We show that SGS neural progenitors exhibit aberrant proliferation, deregulation of oncogenes and suppressors, unresolved DNA damage, and resistance to apoptosis. Mechanistically, we demonstrate that high SETBP1 levels inhibit P53 function through the stabilization of SET, which in turn hinders P53 acetylation. We find that the inheritance of unresolved DNA damage in SGS neurons triggers the neurodegenerative process that can be alleviated either by PARP-1 inhibition or by NAD + supplementation. These results implicate that neuronal death in SGS originates from developmental alterations mainly in safeguarding cell identity and homeostasis., Schinzel-Giedion syndrome (SGS) is a fatal developmental syndrome characterized by severe intellectual and physical deficits due, at least in part, to early neurodegeneration. Here the authors introduce a human SGS model that displays disease-relevant phenotypes to demonstrate that neuronal death in SGS originates from developmental alterations mainly in safeguarding cell identity and homeostasis.

Background and aims Vaccines, to limit SARS-CoV-2 infection, were produced and reliable assays are needed for their evaluation. The WHO produced an International-Standard (WHO-IS) to facilitate the standardization/comparison of serological methods. The WHO-IS, produced in limited amount, was never tested for reproducibility. This study aims at developing a reproducible and accessible working standard (WS) to complement the WHO-IS. Materials and methods Sera from vaccinated individuals were used to produce the WSs. The WHO-IS, the WSs and single serum samples (n = 48) were tested on 6 quantitative serological devices. Neutralization assays were performed for the 48 samples and compared with their antibody titers. Results The WS carry an antibody titer 20-fold higher than the WHO-IS. It was reproducible, showed both good linearity and insignificant intra- and inter-laboratory variability. However, the WSs behave differently from the WHO-IS. Analysis of the 48 samples showed that single correlation factors are not sufficient to harmonize results from different assays. Yet, all the devices predict neutralization activity based on the antibody titer. Conclusions A reproducible and highly concentrated WS, specific for IgG against SARS-CoV-2 Spike-glycoprotein was produced. Such characteristics make it particularly suited for the harmonization of commercially available assays and the consequent evaluation of post-vaccinated individuals.

Ion channels are integral membrane proteins that contain pathways through which ions can flow. By shifting between closed and open conformational states (‘gating’ process), they control passive ion flow through the plasma membrane. Channels can be gated by membrane potential, or specific ligands, or other agents, such as mechanical stimuli. The efficacy of the gating process and the kinetics of subsequent inactivation or desensitization are regulated by intracellular mechanisms. Many types of membrane channels exist, with different degrees of ion selectivity. By controlling ion fluxes, they typically regulate membrane potential and excitability, shape the action potential, trigger muscle contraction and exocytosis (through Ca2+ influx), regulate cell volume and many other cellular processes. In the first part of the chapter, we give a brief introduction to the main physiological aspects of ion channels, which may not be familiar to molecular biologists. Subsequently, as a reference for later chapters, we summarize the main structural and functional features of the channel-proteins presently known to be related to integrin receptors.

Aims Brugada syndrome (BrS) is associated with an increased risk of sudden cardiac death due to ventricular tachycardia/fibrillation (VT/VF) in young, otherwise healthy individuals. Despite SCN5A being the most commonly known mutated gene to date, the genotype–phenotype relationship is poorly understood and remains uncertain. This study aimed to elucidate the genotype–phenotype correlation in BrS. Methods and results Brugada syndrome probands deemed at high risk of future arrhythmic events underwent genetic testing and phenotype characterization by the means of epicardial arrhythmogenic substrate (AS) mapping, and were divided into two groups according to the presence or absence of SCN5A mutation. Two-hundred probands (160 males, 80%; mean age 42.6 ± 12.2 years) were included in this study. Patients harbouring SCN5A mutations exhibited a spontaneous type 1 pattern and experienced aborted cardiac arrest or spontaneous VT/VF more frequently than the other subjects. SCN5A-positive patients exhibited a larger epicardial AS area, more prolonged electrograms and more frequently observed non-invasive late potentials. The presence of an SCN5A mutation explained >26% of the variation in the epicardial AS area and was the strongest predictor of a large epicardial area. Conclusion In BrS, the genetic background is the main determinant for the extent of the electrophysiological abnormalities. SCN5A mutation carriers exhibit more pronounced epicardial electrical abnormalities and a more aggressive clinical presentation. These results contribute to the understanding of the genetic determinants of the BrS phenotypic expression and provide possible explanations for the varying degrees of disease expression.

Different forms of sudden cardiac death have been described, including a recently identified form of genetic arrhythmogenic disorder, named “Triadin KnockOut Syndrome” (TKOS). TKOS is associated with recessive mutations in the TRDN gene, encoding for TRIADIN, but the pathogenic mechanism underlying the malignant phenotype has yet to be completely defined. Moreover, patients with TKOS are often refractory to conventional treatment, substantiating the need to identify new therapeutic strategies in order to prevent or treat cardiac events. The zebrafish (Danio rerio) heart is highly comparable to the human heart in terms of functions, signal pathways and ion channels, representing a good model to study cardiac disorders. In this work, we generated the first zebrafish model for trdn loss-of-function, by means of trdn morpholino injections, and characterized its phenotype. Although we did not observe any gross cardiac morphological defect between trdn loss-of-function embryos and controls, we found altered cardiac rhythm that was recovered by the administration of arrhythmic drugs. Our model will provide a suitable platform to study the effect of TRDN mutations and to perform drug screening to identify new pharmacological strategies for patients carrying TRDN mutations.

Alzheimer's disease is a neurodegenerative disorder and the most common and devastating form of dementia. It affects mainly older people, accounting for 50-80% of dementia cases. The age is the main associated risk factor and based on the onset age, early-onset (EOAD) or late-onset (LOAD) forms are distinguished. AD has a strong impact both on the life-style of patients and their families and on the society, due to the high costs related to social and medical care. So far, despite the great advances in understanding of the AD pathogenesis, there is no a cure for this form of dementia and current available treatments are limited to temporarily relieve symptoms. In this review, firstly we give an overview of the current knowledge of the genetic basis of both forms of AD with a particular emphasis on the insights in the understanding of the pathogenic mechanisms of this disorder. Then we discuss the promising relevance of "omics sciences" and the open challenges of the application of Big Data in promoting precision medicine for AD.

Healthcare professionals are considered to be at high risk of exposure and spread of SARS-CoV-2, and have therefore been considered a priority group in COVID-19 vaccination campaign strategies. However, it must be assumed that the immune response is influenced by numerous factors, including sex and gender. The analysis of these factors is an impact element for stratifying the population and targeting the vaccination strategy. Therefore, a large cohort of healthcare workers participating in the Italian vaccination campaign against SARS-CoV-2 has been studied to establish the impact of sex and gender on vaccination coverage using the Gender Impact Assessment approach. This study shows a significant difference in the antibody titers among different age and sex groups, with a clear decreasing trend in antibody titers in the older age groups. Overall, the serological values were significantly higher in females, the reported side effects are more frequent in females than in males. Therefore, disaggregated data point out how the evaluation of gender factors could be essential in COVID-19 vaccination strategies. On this biomedical and social basis, suggestions are provided to improve the SARS-CoV-2 vaccination campaign in healthcare professionals. Still, they could be adapted to other categories and contexts.

Objectives After exceptional research efforts, several vaccines were developed against SARS-CoV-2 which sustains the pandemic COVID-19. The Comirnaty vaccine showed high efficacy in clinical trials and was the first to be approved for its distribution to the general population. We evaluated the immune response induced by the first vaccine dose in different sex/age groups and subjects with or without naturally present anti-SARS-CoV-2 antibodies. Methods As part of an Italian multicenter project (Covidiagnostix), serum samples from 4,290 health-professionals were serologically tested the day of the first vaccination dose, and 21 days later, using two different instrumentations (Siemens-Healthineers and Roche). Results In total, 97% of samples showed the presence of specific antibodies 21 days after the vaccination dose; the percentage of non-responders increased with age in both genders. Remarkably, naturally seropositive individuals showed antibody persistence up to 11 months and an exceptionally higher vaccination response compared to subjects never infected by SARS-CoV-2. Conclusions This study highlighted the importance of the serological test i) to identify naturally SARS-CoV-2 seropositive individuals and ii) to evaluate the antibody level elicited by the first vaccination dose. Both tests, highlighted differences in the immune response, when subjects were stratified by sex and age, and between naturally seropositive and seronegative subjects. The data obtained show how serological tests could play a crucial role in the triage of the population subjected to the vaccination campaign for COVID-19. The definition of suitable instrumentation-specific thresholds is needed to correctly follow eventually acquired post-vaccination immunity in the general population.

Background The first COVID-19 vaccines are being distributed to the general population. However, the shortage of doses is slowing down the goal of reaching herd immunity. The aim of the study was to verify whether previously SARS-CoV-2 infected subjects, a considerable portion of the population, should receive the same vaccination treatment of seronegative individuals. Methods Health-professionals either recovered from COVID-19 or never infected by SARS-CoV-2 were serologically tested at different time-points right before, and several days after, vaccination. Results Previously infected individuals showed humoral immune responses, 21 days after the first dose, that was approximately 10-folds higher than the seronegative group 21 days after the second dose. Seropositivity persists for at least 11 months. Conclusion During a shortage of COVID-19 vaccine doses, previously SARS-CoV-2 infected individuals should be dispensed from the vaccination campaign. When dose availability returns to normality, injection of a single dose for seropositive individuals should be considered.

Objectives The rRT-PCR test, the current gold standard for the detection of coronavirus disease (COVID-19), presents with known shortcomings, such as long turnaround time, potential shortage of reagents, false-negative rates around 15–20%, and expensive equipment. The hematochemical values of routine blood exams could represent a faster and less expensive alternative. Methods Three different training data set of hematochemical values from 1,624 patients (52% COVID-19 positive), admitted at San Raphael Hospital (OSR) from February to May 2020, were used for developing machine learning (ML) models: the complete OSR dataset (72 features: complete blood count (CBC), biochemical, coagulation, hemogasanalysis and CO-Oxymetry values, age, sex and specific symptoms at triage) and two sub-datasets (COVID-specific and CBC dataset, 32 and 21 features respectively). 58 cases (50% COVID-19 positive) from another hospital, and 54 negative patients collected in 2018 at OSR, were used for internal-external and external validation. Results We developed five ML models: for the complete OSR dataset, the area under the receiver operating characteristic curve (AUC) for the algorithms ranged from 0.83 to 0.90; for the COVID-specific dataset from 0.83 to 0.87; and for the CBC dataset from 0.74 to 0.86. The validations also achieved good results: respectively, AUC from 0.75 to 0.78; and specificity from 0.92 to 0.96. Conclusions ML can be applied to blood tests as both an adjunct and alternative method to rRT-PCR for the fast and cost-effective identification of COVID-19-positive patients. This is especially useful in developing countries, or in countries facing an increase in contagions.

Brugada syndrome (BrS) is diagnosed by the presence of an elevated ST-segment and can result in sudden cardiac death. The most commonly found mutated gene is SCN5A, which some argue is the only gene that has been definitively confirmed to cause BrS, while the potential causative effect of other genes is still under debate. While the issue of BrS genetics is currently a hot topic, current knowledge is not able to result in molecular confirmation of over half of BrS cases. Therefore, it is difficult to develop research models with wide potential. Instead, the clinical genetics first need to be better understood. In this study, we provide crucial human data on the novel heterozygous variant NM_198056.2:c.4285G>A (p.Val1429Met) in the SCN5A gene, and demonstrate its segregation with BrS, suggesting a pathogenic effect. These results provide the first disease association with this variant and are crucial clinical data to communicate to basic scientists, who could perform functional studies to better understand the molecular effects of this clinically-relevant variant in BrS.

Summary. Background. The Lombardy region, Italy, has been severely affected by COVID-19. During the epidemic peak, in March 2020, patients needing intensive care unit treatments were approximately 10% of those infected. This fraction decreased to approximately 2% in the second part of April, and to 0.4% at the beginning of July. COVID-19 is characterized by several biochemical abnormalities whose discrepancy from normal values was associated to the severity of the disease. The aim of this retrospective study was to compare the biochemical patterns of patients during and after the pandemic peak in order to verify whether later patients were experiencing a milder COVID-19 course, as anecdotally observed by several clinicians of the same Hospital. Material and Methods. The laboratory findings of two equivalent groups of 84 patients each, admitted at the emergency department of the San Raffaele Hospital (Milan, Italy), during March and April respectively, were analyzed and compared. Results. White blood cell, platelets, lymphocytes and lactate dehydrogenase showed a statistically significant improvement (i.e. closer or within the normal clinical range) in the April group compared to March. Creatinine, C-reactive protein, Calcium and liver enzymes, were also pointing in that direction, although the differences were not significant. Discussion. The laboratory findings analyzed in this study were consistent with a milder COVID-19 course in the April group. After excluding several hypotheses, we concluded that our observation was likely the consequence of the lockdown strategy enforcement, which, by imposing social distancing and the use of respiratory protective devices, reduced viral loads upon infection. (www.actabiomedica.it).

Cardiac laminopathies, associated with mutations in the LMNA gene, encompass a wide spectrum of clinical manifestations, involving electrical and mechanical alterations of cardiomyocytes. Thus, dilated cardiomyopathy, bradyarrhythmias and atrial or ventricular tachyarrhythmias may occur in a number of combined phenotypes. Nowadays, some attempt has been made to identify clinical predictors for the most life-threatening complications of LMNA-associated heart disease, i.e. sudden cardiac death and end-stage heart failure. The goal of this manuscript is to combine the most recent evidences in an updated review to show the state-of-the-art of such a complex disease group. This is supposed to be the starting point to collect more data and design new ad hoc studies to identify clinically useful predictors to stratify risk in mutation carriers, including probands and their asymptomatic relatives.

[This corrects the article DOI: 10.4103/1673-5374.265554].

Brugada syndrome (BrS) is marked by an elevated ST-segment elevation and increased risk of sudden cardiac death. Variants in the SCN5A gene are considered to be molecular confirmation of the syndrome in about one third of cases, while the genetics remain a mystery in about half of the cases, with the remaining cases being attributed to variants in any of a number of genes. Before research models can be developed, it is imperative to understand the genetics in patients. Even data from humans is complicated, since variants in the most common gene in BrS, SCN5A, are associated with a number of pathologies, or could even be considered benign, depending on the variant. Here, we provide crucial human data on a novel NM_198056.2:c.2091G>A (p.Trp697X) point-nonsense heterozygous variant in the SCN5A gene, as well as its segregation with BrS. The results herein suggest a pathogenic effect of this variant. These results could be used as a stepping stone for functional studies to better understand the molecular effects of this variant in BrS.

Methods: 164 LMNA mutation carriers (median age 38 y; 51.2% females) were enrolled from 13 referral centers. All of them underwent a combined C and N assessment at the time of enrollment and 2/y for 10 y median FU, including ECG, Holter monitoring, and imaging data. Further detailed clinical information were collected retrospectively. The purpose of the study was to describe natural history of the disease and to stratify cardiac risk based on an innovative multispecialistic approach.

Background Mutations in the LMNA (lamin A/C) gene have been associated with neuromuscular and cardiac manifestations, but the clinical implications of these signs are not well understood. Objective To learn more about the natural history of LMNA-related disease. Design Observational study. Setting 13 clinical centers in Italy from 2000 through 2018. Patients 164 carriers of an LMNA mutation. Measurements Detailed cardiologic and neurologic evaluation at study enrollment and for a median of 10 years of follow-up. Results The median age at enrollment was 38 years, and 51% of participants were female. Neuromuscular manifestations preceded cardiac signs by a median of 11 years, but by the end of follow-up, 90% of the patients had electrical heart disease followed by structural heart disease. Overall, 10 patients (6%) died, 14 (9%) received a heart transplant, and 32 (20%) had malignant ventricular arrhythmias. Fifteen patients had gait loss, and 6 had respiratory failure. Atrial fibrillation and second- and third-degree atrioventricular block were observed, respectively, in 56% and 51% of patients with combined cardiac and neuromuscular manifestations and 37% and 33% of those with heart disease only. Limitations Some of the data were collected retrospectively. Neuromuscular manifestations were more frequent in this analysis than in previous studies. Conclusion Many patients with an LMNA mutation have neurologic symptoms by their 30s and develop progressive cardiac manifestations during the next decade. A substantial proportion of these patients will have life-threatening neurologic or cardiologic conditions. Primary funding source None.

AIMS: The Na(+) channel mutation (p.S216L), previously associated with type 3 long-QT syndrome (LQT3) phenotype, and a common polymorphism (p.H558R) were detected in a patient with an intermittent Brugada syndrome (BS) ECG pattern. The study was aimed to assess the p.S216L electrical phenotype, its modulation by p.H558R, and to identify abnormalities compatible with a mixed BS-LQT3 phenotype. METHODS AND RESULTS: The mutation was expressed alone (S216L channels), or in combination with the polymorphism (S216L-H558R channels), in a mammalian cell line (TSA201). Functional analysis included standard voltage clamp and dynamic clamp with endo- and epicardial action potential waveforms. Expression of S216L channels was associated with a 60% reduction in maximum Na(+) current (I(Na)) density, attributable to protein misfolding (rescued by mexiletine pretreatment) and moderate slowing of inactivation. I(Na) density partially recovered in S216L-H558R channels, but I(Na) inactivation and its recovery were further delayed. The persistent component of I(Na) (I(NaL)) was unchanged. Under dynamic clamp conditions, I(Na) decreased in S216L channels and displayed a 'resurgent' component during late repolarization. In S216L-H558R channels, I(Na) density partially recovered and did not display a resurgent component. I(Na) changes during dynamic clamp were interpreted by numerical modelling. CONCLUSION: The BS pattern of p.S216L might result from a decrease in I(Na) density, which masked gating abnormalities that might otherwise result in a LQT phenotype. The p.H558R polymorphism decreased p.S216L expressivity, partly by lessening p.S216L effects and partly through the induction of further gating abnormalities suitable to blunt p.S216L effects during repolarization.

Carbamazepine (5H-dibenz[b,f]azepine-5-carboxamide) and oxcarbazepine (10,11-dihydro-10-oxo-5H-dibenz[b,f]azepine-5-carboxamide) are widely used for the treatment of partial epilepsy. Recent work indicates that these drugs, in addition to targeting voltage-gated Na(+) channels, can modulate ligand-gated channels. These compounds appear to be particularly effective for treatment of nocturnal frontal lobe epilepsy, which can be caused by mutant neuronal nicotinic receptors. We compared the effects of carbamazepine and oxcarbazepine on heteromeric nicotinic receptors to better understand the underlying mechanism of the effect of these drugs in epileptic patients. Receptors were expressed in cell lines and studied by patch-clamp methods at -60 mV. For alpha2beta4 receptors activated with 100 microM nicotine, IC(50) for carbamazepine was 49 microM. Receptors in which alpha2 was substituted with alpha2-I279 N, linked to autosomal dominant nocturnal frontal lobe epilepsy, had an IC(50) of 21 microM. For oxcarbazepine, the IC(50) was larger than 500 microM for wild-type receptors and approximately 100 microM for mutant receptors. A similar inhibition was observed in the presence of 10 microM nicotine, indicating a non-competitive mechanism. The monohydroxy derivative (MHD) of oxcarbazepine, clinically the most relevant compound, was tested on both alpha2beta4 and alpha4beta2 receptors, to obtain a broader view of its possible physiological effects. At the typical concentration present in blood (100 microM), MHD produced an approximate 40% channel block on alpha4beta2, but no significant effect on alpha2beta4 receptors. Oxcarbazepine and MHD retarded the channel deactivation, suggesting that these compounds produce open channel block. These results may explain the particular efficacy of these drugs in nocturnal frontal lobe epilepsy.

Sleep has traditionally been recognized as a precipitating factor for some forms of epilepsy, although differential diagnosis between some seizure types and parasomnias may be difficult. Autosomal dominant frontal lobe epilepsy is characterized by nocturnal seizures with hyperkinetic automatisms and poorly organized stereotyped movements and has been associated with mutations of the α4 and β2 subunits of the neuronal nicotinic acetylcholine receptor. We performed a clinical and molecular genetic study of a large pedigree segregating sleep-related epilepsy in which seizures are associated with fear sensation, tongue movements, and nocturnal wandering, closely resembling nightmares and sleep walking. We identified a new genetic locus for familial sleep-related focal epilepsy on chromosome 8p12.3-8q12.3. By sequencing the positional candidate neuronal cholinergic receptor α2 subunit gene (CHRNA2), we detected a heterozygous missense mutation, I279N, in the first transmembrane domain that is crucial for receptor function. Whole-cell recordings of transiently transfected HEK293 cells expressing either the mutant or the wild-type receptor showed that the new CHRNA2 mutation markedly increases the receptor sensitivity to acetylcholine, therefore indicating that the nicotinic α2 subunit alteration is the underlying cause. CHRNA2 is the third neuronal cholinergic receptor gene to be associated with familial sleep-related epilepsies. Compared with the CHRNA4 and CHRNB2 mutations reported elsewhere, CHRNA2 mutations cause a more complex and finalized ictal behavior. © 2006 by The American Society of Human Genetics. All rights reserved.