RESUMO
Epilepsy is a neurological disorder characterised by two or more unprovoked seizures. The high prevalence and incidence of epilepsy globally, especially in Asia, has remained a big concern over the course of centuries. Patients are usually prescribed the already known anti-epileptic drugs, but even after going through three different generations of anti-epileptic drugs, some people still suffer from drug-resistant form of epilepsy. These patients are usually prescribed a higher dose of anti-epileptic drugs, which results in more adverse effects. That is why new treatment options, like herbal extracts, should be explored for patients who do not respond to the classic anti-epileptic drugs. The current narrative review was planned to explore if herbal extracts can be the future for the treatment of drug-resistant epilepsy.
Assuntos
Epilepsia Resistente a Medicamentos , Epilepsia , Humanos , Anticonvulsivantes/uso terapêutico , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Epilepsia/tratamento farmacológico , Convulsões/tratamento farmacológico , Extratos Vegetais/uso terapêuticoRESUMO
Hypermanganesaemia with dystonia, polycythemia, and cirrhosis (HMDPC) is a rare genetic and autosomal recessive disorder that occurs due to mutation of the SLC3A10 gene, which encodes the manganese (Mn) transporter in the body; as a result, Mn accumulates in the brain, liver and muscles. This accumulation leads to symptoms of generalized dystonia, polycythemia, and hypermanganesaemia. In this report, we present the case of a 2½-year-old baby girl (patient) with complaints of lower limb weakness and increased difficulty in walking for six months. Her laboratory test results showed deranged values with increased Mn levels in the body. The patient was put on six cycles of EDTA therapy, which showed an improvement in her condition. This case report is presented to create awareness about a rare genetic disorder with an effective treatment in some cases. Thus, more work and research is required to understand and develop better treatment options for this disease.
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Proteínas de Transporte de Cátions , Distonia , Distúrbios Distônicos , Doenças Metabólicas , Policitemia , Humanos , Feminino , Adulto Jovem , Adulto , Proteínas de Transporte de Cátions/genética , Distonia/genética , Mutação , Manganês/metabolismo , Cirrose Hepática/complicaçõesRESUMO
This study was designed to determine the prevalence and type of malaria cases that presented throughout the year 2014 in a tertiary care hospital in Karachi, Pakistan. A total of 1099 cases, (377 females, 722 males) were reported. Plasmodium vivax (P. vivax) was discovered in 93.7% cases compared to 6.3% Plasmodium falciparum (P. falciparum). Based on the highest and lowest weather temperatures, in summer (June, July and August) and in winter (December, January and February) were differentiated. The number of cases were greater during summer months compared to winter. Interestingly, the ratio of P. falciparum to P. vivax during winter was greater compared to summer. Finally, there was a strong correlation between increasing humidity and number of malaria cases. These findings show that even though the incidence of malaria is higher in summer, malaria cases are still reported in winter. Furthermore, the probability of finding P. falciparum (which causes cerebral malaria ) is higher in winter.
Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paquistão/epidemiologia , Prevalência , Estudos Retrospectivos , Estações do Ano , Centros de Atenção Terciária , Tempo (Meteorologia) , Adulto JovemRESUMO
Isolated Hemimegalencephaly (iHME) is a rare form of congenital malformation of cortical development.It is characterized by enlargement of all or part of one cerebral hemisphere. It typically presents with intractable seizures, mental retardation, developmental delay, contralateral hemiparesis and hemianopia. The patient was a five and half month's old baby girl who presented first with focal seizures at 10th day of life. No other physical or behavioral abnormality was noted. However, Initial EEG showed excessive sharp EEG transients more over the right hemisphere, repeated EEG showed spikes, polyspikes, sharps and slow wave discharges predominately over right hemisphere. MRI brain showed asymmetric enlargement of the right cerebral hemisphere, suggestive of hemimegalencephaly. Initial treatment with anti-epileptics was successful in controlling the seizures but later on the seizures became intractable even on polytherapy. Identification of this and similar cases of iHME can help us better understand this disorder and its associated symptoms and eventually help us develop better treatment options for it.
Assuntos
Anticonvulsivantes/uso terapêutico , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Hemimegalencefalia/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/etiologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletroencefalografia , Epilepsia/tratamento farmacológico , Epilepsia/etiologia , Epilepsia/fisiopatologia , Feminino , Hemimegalencefalia/complicações , Hemimegalencefalia/fisiopatologia , Humanos , Lactente , Imageamento por Ressonância MagnéticaRESUMO
OBJECTIVE: In this study we implemented the "flipped classroom" model to enhance active learning in medical students taking neurosciences module at Aga Khan University, Karachi. METHODS: Ninety eight undergraduate medical students participated in this study. The study was conducted from January till March 2017. Study material was provided to students in form of video lecture and reading material for the non-face to face sitting, while face to face time was spent on activities such as case solving, group discussions, and quizzes to consolidate learning under the supervision of faculty. To ensure deeper learning, we used pre- and post-class quizzes, work sheets and blog posts for each session. Student feedback was recorded via a likert scale survey. RESULTS: Eighty four percent students gave positive responses towards utility of flipped classroom in terms of being highly interactive, thought provoking and activity lead learning. Seventy five percent of the class completed the pre-session preparation. Students reported that their queries and misconceptions were cleared in a much better way in the face-to-face session as compared to the traditional setting (4.09 ±1.04). CONCLUSION: Flipped classroom(FCR) teaching and learning pedagogy is an effective way of enhancing student engagement and active learning. Thus, this pedagogy can be used as an effective tool in medical schools.
RESUMO
The GABA(A) receptor (GABA(A)R) α1 subunit mutation, A322D, causes autosomal dominant juvenile myoclonic epilepsy (JME). Previous in vitro studies demonstrated that A322D elicits α1(A322D) protein degradation and that the residual mutant protein causes a dominant-negative effect on wild type GABA(A)Rs. Here, we determined the effects of heterozygous A322D knockin (Het(α1)AD) and deletion (Het(α1)KO) on seizures, GABA(A)R expression, and motor cortex (M1) miniature inhibitory postsynaptic currents (mIPSCs) at two developmental time-points, P35 and P120. Both Het(α1)AD and Het(α1)KO mice experience absence seizures at P35 that persist at P120, but have substantially more frequent spontaneous and evoked polyspike wave discharges and myoclonic seizures at P120. Both mutant mice have increased total and synaptic α3 subunit expression at both time-points and decreased α1 subunit expression at P35, but not P120. There are proportional reductions in α3, ß2, and γ2 subunit expression between P35 and P120 in wild type and mutant mice. In M1, mutants have decreased mIPSC peak amplitudes and prolonged decay constants compared with wild type, and the Het(α1)AD mice have reduced mIPSC frequency and smaller amplitudes than Het(α1)KO mice. Wild type and mutants exhibit proportional increases in mIPSC amplitudes between P35 and P120. We conclude that Het(α1)KO and Het(α1)AD mice model the JME subsyndrome, childhood absence epilepsy persisting and evolving into JME. Both mutants alter GABA(A)R composition and motor cortex physiology in a manner expected to increase neuronal synchrony and excitability to produce seizures. However, developmental changes in M1 GABA(A)Rs do not explain the worsened phenotype at P120 in mutant mice.
Assuntos
Córtex Motor/fisiopatologia , Epilepsia Mioclônica Juvenil/fisiopatologia , Inibição Neural/fisiologia , Convulsões/fisiopatologia , Animais , Modelos Animais de Doenças , Potenciais Pós-Sinápticos Inibidores/fisiologia , Camundongos , Camundongos Transgênicos , Potenciais Pós-Sinápticos em Miniatura/fisiologia , Epilepsia Mioclônica Juvenil/genética , Fenótipo , Receptores de GABA-A/genética , Convulsões/genéticaRESUMO
Hereditary Sensory Autonomic Neuropathy II (HSAN II) is a rare genetic disorder, characterized by severe loss of pain, temperature and touch sensation. Injuries in these patients can progress to necrosis and shedding of digits and limbs. Here we report two cases of HSAN II belonging to a Pakistani family. Individual 1, a forty five year old man, had complete loss of pain sensation since birth. Self-mutilation and complication of injuries resulted in the shedding of all the digits and right foot and surgical amputation of left leg. Individual 2, a five year old girl,had delay in healing of wounds and self-mutilation. Examination showed a complete lack of pain sensation throughout her body and hyporeflexia. As the genetic cause of HSAN II is unknown, identification of more patients will allow further research on this disease and possibly develop a cure.
Assuntos
Neuropatias Hereditárias Sensoriais e Autônomas/genética , Neuropatias Hereditárias Sensoriais e Autônomas/patologia , Doenças Raras/genética , Doenças Raras/patologia , Automutilação/patologia , Pré-Escolar , Feminino , Neuropatias Hereditárias Sensoriais e Autônomas/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Paquistão , Linhagem , Doenças Raras/psicologia , Automutilação/etiologiaRESUMO
Patients with generalized epilepsy exhibit cerebral cortical disinhibition. Likewise, mutations in the inhibitory ligand-gated ion channels, GABAA receptors (GABAARs), cause generalized epilepsy syndromes in humans. Recently, we demonstrated that heterozygous knock-out (Hetα1KO) of the human epilepsy gene, the GABAAR α1 subunit, produced absence epilepsy in mice. Here, we determined the effects of Hetα1KO on the expression and physiology of GABAARs in the mouse cortex. We found that Hetα1KO caused modest reductions in the total and surface expression of the ß2 subunit but did not alter ß1 or ß3 subunit expression, results consistent with a small reduction of GABAARs. Cortices partially compensated for Hetα1KO by increasing the fraction of residual α1 subunit on the cell surface and by increasing total and surface expression of α3, but not α2, subunits. Co-immunoprecipitation experiments revealed that Hetα1KO increased the fraction of α1 subunits, and decreased the fraction of α3 subunits, that associated in hybrid α1α3ßγ receptors. Patch clamp electrophysiology studies showed that Hetα1KO layer VI cortical neurons exhibited reduced inhibitory postsynaptic current peak amplitudes, prolonged current rise and decay times, and altered responses to benzodiazepine agonists. Finally, application of inhibitors of dynamin-mediated endocytosis revealed that Hetα1KO reduced base-line GABAAR endocytosis, an effect that probably contributes to the observed changes in GABAAR expression. These findings demonstrate that Hetα1KO exerts two principle disinhibitory effects on cortical GABAAR-mediated inhibitory neurotransmission: 1) a modest reduction of GABAAR number and 2) a partial compensation with GABAAR isoforms that possess physiological properties different from those of the otherwise predominant α1ßγ GABAARs.
Assuntos
Córtex Cerebral/metabolismo , Endocitose , Epilepsia Tipo Ausência/genética , Epilepsia Tipo Ausência/fisiopatologia , Alelos , Animais , Benzodiazepinas/farmacologia , Células COS , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Córtex Cerebral/efeitos dos fármacos , Chlorocebus aethiops , Modelos Animais de Doenças , Dinaminas/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Epilepsia Tipo Ausência/patologia , Agonistas de Receptores de GABA-A/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Heterozigoto , Humanos , Cinética , Camundongos , Camundongos Knockout , Modelos Biológicos , Ligação Proteica/efeitos dos fármacos , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Ácido gama-Aminobutírico/metabolismoRESUMO
INTRODUCTION: In Pakistan, the reported carrier rate of thalassaemia is estimated to be 5%-8% with 5000 new patients diagnosed every year. Several known systemic complications of beta thalassaemia major have been studied, but no studies are conducted to assess ocular complications among these patients from our population. METHODS: It was a cross-sectional study design conducted at three private and public sector centres in Pakistan. We recruited 203, 11-17 years old children with beta thalassaemia major in our study. Frequency of overall ocular complications such as retinal pigment epithelium degeneration, visual field defects, increased retinal vascular tortuosity, lenticular opacities, anterior segment abnormality, etc among beta thalassaemia patients were verified by an ophthalmologist. RESULTS: On univariate analysis male gender (prevalence ratio (PR): 1.023 (0.903 to 1.160), OGTT levels (PR: 0.99 (0.978 to 1.003) and serum calcium levels (PR: 0.716 (0.616 to 0.936)) were significantly associated with ocular complications. However, on multivariable analysis after adjusting for covariates we observed that the prevalence of ocular complications was 88% higher in males as compared with females. Moreover, with every one unit increase in serum calcium levels the prevalence of ocular complications were decreased by 24%. CONCLUSION: Our study results showed that the frequency of ocular complications in beta thalassaemia children was 22.7%. Male gender was a risk factor for ocular complications among children with beta thalassaemia. However, high calcium levels among these patients were found to be protective for ocular complications.
Assuntos
Catarata , Talassemia , Talassemia beta , Criança , Feminino , Humanos , Masculino , Adolescente , Talassemia beta/complicações , Estudos Transversais , Cálcio , Talassemia/complicações , Catarata/complicaçõesRESUMO
Autosomal dominant mutations S326fs328X and A322D in the GABA(A) receptor α1 subunit are associated with human absence epilepsy and juvenile myoclonic epilepsy, respectively. Because these mutations substantially reduce α1 subunit protein expression in vitro, it was hypothesized that they produce epilepsy by causing α1 subunit haploinsufficiency. However, in a mixed background strain of mice, α1 subunit deletion does not reduce viability or cause visually apparent seizures; the effects of α1 subunit deletion on electroencephalography (EEG) waveforms were not investigated. Here, we determined the effects of α1 subunit loss on viability, EEG spike-wave discharges and seizures in congenic C57BL/6J and DBA/2J mice. Deletion of α1 subunit caused strain- and sex-dependent reductions in viability. Heterozygous mice experienced EEG discharges and absence-like seizures within both background strains, and exhibited a sex-dependent effect on the discharges and viability in the C57BL/6J strain. These findings suggest that α1 subunit haploinsufficiency can produce epilepsy and may be a major mechanism by which the S326fs328X and A322D mutations cause these epilepsy syndromes.
Assuntos
Epilepsia Tipo Ausência/genética , Receptores de GABA-A/deficiência , Animais , Encéfalo/fisiopatologia , Eletroencefalografia , Epilepsia Tipo Ausência/fisiopatologia , Feminino , Heterozigoto , Homozigoto , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Receptores de GABA-A/genéticaRESUMO
INTRODUCTION: Diabetes mellitus is a chronic metabolic disorder with an increasing prevalence worldwide. Reduction in blood insulin level alters brain function by inducing oxidative stress with changes in dopamine and norepinephrine neurotransmission, ultimately leading to neuropsychological symptoms. The efficacy of currently available psychotropic drugs is not satisfactory. Therefore, this study was conducted to explore the beneficial effects of a combination of the natural herbs, saffron and chamomile, in treating diabetes and its resultant neuropsychological effects using a rodent model of diabetes mellitus. METHOD: The rats were randomly divided in to eight groups (n = 10), healthy control (HC), diabetic control (DC) and six groups of diabetic rats treated with various concentrations and combinations of saffron and chamomile. Diabetic treatment groups individually received methanolic extract and water decoction of chamomile (30 mg/kg) and saffron (10mg/kg) and their combined half doses (saffron 5mg/kg and chamomile 15mg/kg) for two weeks. Open field test (OFT) and forced swim test (FST) were used to measure the anxiolytic and antidepressant effects of herbs, respectively. Finally, biochemical, and neurochemical estimations were made. RESULTS: The present study suggests the therapeutic effects of herbs especially in co-administrated decoction, against diabetes with improved antioxidant profile and enhanced levels of dopamine and norepinephrine. Anxiolytic and antidepressant effects were evident with improvements in the OFT and FST. Examination of the cortex of the diabetic group revealed cellular damage and tangle formation, which indicates advanced stages of dementia. CONCLUSION: This study shows that the use of a combination of saffron and chamomile improves diabetes control and reduces its related psychiatric effects.
Assuntos
Ansiolíticos , Crocus , Diabetes Mellitus Experimental , Ratos , Camundongos , Animais , Camomila , Diabetes Mellitus Experimental/metabolismo , Ansiolíticos/uso terapêutico , Modelos Animais de Doenças , Dopamina/uso terapêutico , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Antidepressivos/uso terapêutico , Norepinefrina/uso terapêuticoRESUMO
BACKGROUND: Glioblastoma multiforme (GBM) is the most malignant, aggressive and common form of primary brain cancer. Currently, GBM is considered to be a homogenous mass as all its margins are treated equally at the time of resection. However, it is not known whether radiologically distinct regions of GBM are also distinct at molecular level. We conducted this study to see if radiologically distinct regions were also different at the molecular level. METHODS: In 20 patients, MRI derived variance known as Apparent Diffusion Coefficient (ADC) was plotted against Contrast Enhancement (CE). Four radiologically distinct regions were identified: 1) high ADC and low CE; 2) low ADC and low CE; 3) high ADC and high CE; and 4) low ADC and high CE. Biopsy samples were collected from these four regions of interest in each patient and immunohistochemistry was conducted to characterize cellular features and identify oncogene and stem cell marker expressing cells. RESULTS: Markedly increased nuclear pleomorphism, cellularity and necrosis were seen in region 2. Oncogene IDH was expressed in all regions, however, it was highest in region 4. Stem cell marker, CD44 expression was highest in region 1 and lowest in region 2 and 3. The expression of CD133 was highest in region 3. CONCLUSIONS: This study shows that ADC/CE plot can divide GBM into four regions, whose heterogeneity is evidenced by differential expression of nuclear pleomorphism, necrosis, cellularity and mitotic rate as well as the expression of oncogene and stem cell markers.
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Neoplasias Encefálicas , Glioblastoma , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Imagem de Difusão por Ressonância Magnética , Glioblastoma/diagnóstico por imagem , Glioblastoma/genética , Humanos , Imageamento por Ressonância Magnética , RadiografiaRESUMO
OBJECTIVE: To assess the general practitioners (GP) knowledge regarding the diagnosis and initial drug therapy for acute myocardial infarction (AMI). METHODS: A questionnaire-based survey was conducted in randomly selected GPs of Karachi. Doctors working in community as GPs who were registered medical practitioners having a Bachelor of Medicine & Bachelor of Surgery degree were included in the study. Doctors working at tertiary care facilities or having a post graduate degree or post graduate training in a specialty other than family medicine were excluded from the study. RESULTS: A total of 186 GPs participated in our study. GPs who studied research journals were 2.33 times more likely to investigate serum cardiac troponins levels for the diagnosis of AMI compared to those who did not study research journals (P = 0.02). Twenty six percent of the GPs said that they would refer a patient with suspected AMI without treatment, while 76% said that they would consider some treatment prior to referral. Fifty eight percent of the GPs identified ST segment elevation myocardial infarction (STEMI) of < 12 hours duration as an indication of thrombolysis while 28% identified posterior wall AMI as a thrombolytic indication. CONCLUSION: GPs, although adequately aware of the presenting features of AMI, were lacking in knowledge regarding the means for confirmation of diagnosis, initial drug therapy and were less likely to carry management steps in their practice.
Assuntos
Competência Clínica , Infarto do Miocárdio/diagnóstico , Médicos de Família/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Doença Aguda , Prescrições de Medicamentos , Eletrocardiografia , Feminino , Humanos , Masculino , Infarto do Miocárdio/terapia , Prática Profissional , Inquéritos e Questionários , Terapia TrombolíticaRESUMO
High-grade gliomas possess internal pathological heterogeneity. Selective sampling of different tumor regions can help in the study of this heterogeneity. In this report, we have described the use of a novel navigation and optical system for the selective regional sampling of a high-grade glioma lesion. A 45-year-old gentleman presented to us with complaints of intermittent frontal headaches for past eight months. On examination, he had subtle pyramidal weakness in left upper and lower extremities. Magnetic resonance imaging (MRI) showed a large contrast-enhancing, space-occupying lesion in the right frontal lobe causing perilesional edema and midline shift. We marked four different regions on the preoperative MRI using apparent diffusion coefficient (ADC) mapping and contrast enhancement pattern in four different combinations using presurgical planning software (BrightMatter™ Plan) (Synaptive Medical, Inc., Toronto, Canada). These pre-identified areas were exported into BrightMatter™âââââââ Servo (Synaptive Medical, Toronto, Canada), an integrated robotic video microscope with a neuronavigation system where these areas were selectively sampled and sent for analysis. The BrightMatter™âââââââ Servo not only helped us to the target areas but also helped to identify a safe trajectory, respecting white matter tracts. Histopathology showed a neoplastic lesion composed of mononuclear round cells with the perinuclear halo in a fibrillary stroma with admixed mini-gemistocytes consistent with the diagnosis of a Grade 3 anaplastic astrocytoma. A selective regional sampling of the gliomas can be reliably performed using BrightMatter™âââââââ technologies to study the pathological heterogeneity of these lesions.
RESUMO
Epilepsy is common disorder that affects over 50 million people worldwide. Birds remain a promising yet largely under-explored model of epilepsy. This study reports the comparison of the response of two species of birds, Australian Parrots (APs) and Sparrows (SPs), to a pro-epileptic drug, Pentylenetetrazole (PTZ). PTZ injections caused myoclonic jerks (MCJs) and tonic clonic seizures (TCSs) in both species. The frequency of MCJs in APs was greater at the dose of 75mg/kg compared to both 50mg/kg and 25mg/kg while it was not significantly different in SPs. The comparison of APs and SPs showed that the frequency of MCJs was greater in APs compared to SPs at 25mg/kg and 75mg/kg while its latency was reduced at 25mg/kg and 50mg/kg. Interestingly SPs had a reduced latency of TCSs compared to APs at 75mg/kg. Glutamatergic and Gabaergic cell count was conducted to determine an association with the epileptic response to PTZ. The Glutamatergic cell counts for SPs was significantly greater than APs and conversely the Gabaergic cell counts in APs was higher compared to SPs. The reason for this difference in findings needs to be further investigated. This study shows that birds, and APs and SPs in particular, are a valid, interesting and under-explored model of epilepsy that should be further explored in order to understand the mysteries of epilepsy.
Assuntos
Convulsivantes/farmacologia , Papagaios , Pentilenotetrazol/farmacologia , Pardais , Animais , Relação Dose-Resposta a Droga , Ácido Glutâmico/metabolismo , Imuno-Histoquímica , Mioclonia/induzido quimicamente , Mioclonia/fisiopatologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Papagaios/anatomia & histologia , Papagaios/fisiologia , Fenótipo , Convulsões/induzido quimicamente , Convulsões/fisiopatologia , Pardais/anatomia & histologia , Pardais/fisiologia , Especificidade da Espécie , Telencéfalo/citologia , Telencéfalo/efeitos dos fármacos , Telencéfalo/fisiologia , Ácido gama-Aminobutírico/metabolismoRESUMO
Science is ideally suited to connect people from different cultures and thereby foster mutual understanding. To promote international life science collaboration, we have launched "The Science Bridge" initiative. Our current project focuses on partnership between Western and Middle Eastern neuroscience communities.
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Cooperação Internacional , Neurociências/história , Europa (Continente) , História do Século XV , História do Século XXI , História Antiga , História Medieval , Humanos , Oriente MédioRESUMO
Individuals with autosomal dominant juvenile myoclonic epilepsy are heterozygous for a GABA(A) receptor alpha1 subunit mutation (alpha1A322D). GABA(A) receptor alphabetagamma subunits are arranged around the pore in a beta-alpha-beta-alpha-gamma sequence (counterclockwise from the synaptic cleft). Therefore, each alpha1 subunit has different adjacent subunits, and heterozygous expression of alpha1(A322D), beta, and gamma subunits could produce receptors with four different subunit arrangements: beta-alpha1-beta-alpha1-gamma (wild type); beta-alpha1(A322D)-beta-alpha1-gamma (Het(betaalphabeta)); beta-alpha1-beta-alpha1(A322D)-gamma (Het(betaalphagamma));beta-alpha1(A322D)-beta-alpha1(A322D)-gamma (homozygous). Expression of a 1:1 mixture of wild-type andalpha1(A322D) subunits with beta2S and gamma2S subunits (heterozygous transfection) produced smaller currents than wild type and much larger currents than homozygous mutant transfections. Western blot and biotinylation assays demonstrated that the amount of total and surface alpha1 subunit from heterozygous transfections was also intermediate between those of wild-type and homozygous mutant transfections. alpha1(A322D) mutations were then made in covalently tethered triplet (gamma2S-beta2S-alpha1) and tandem (beta2S-alpha1) concatamers to target selectively alpha1(A322D) to each of the asymmetric alpha1 subunits. Coexpression of mutant and wild-type concatamers resulted in expression of either Het(betaalphabeta) or Het(betaalphagamma) receptors. Het(betaalphabeta) currents were smaller than wild type and much larger than Het(betaalphagamma) and homozygous currents. Furthermore, Het(betaalphabeta) transfections contained less beta-alpha concatamer than wild type but more than both Het(betaalphagamma) and homozygous mutant transfections. Thus, whole-cell currents and protein expression of heterozygous alpha1(A322D)beta2Sgamma2S receptors depended on the position of the mutant alpha1 subunit, and GABA(A) receptor currents in heterozygous individuals likely result primarily from wild-type and Het(betaalphabeta) receptors with little contribution from Het(betaalphagamma) and homozygous receptors.