Defective cystathionine beta-synthase regulation by S-adenosylmethionine in a partially pyridoxine responsive homocystinuria patient.

We determined the molecular basis of cystathionine beta-synthase (CBS) deficiency in a partially pyridoxine-responsive homocystinuria patient. Direct sequencing of the entire CBS cDNA revealed the presence of a homozygous G1330A transition. This mutation causes an amino acid change from aspartic acid to asparagine (D444N) in the regulatory domain of the protein and abolishes a TaqI restriction site at DNA level. Despite the homozygous mutation, CBS activities in extracts of cultured fibroblasts of this patient were not in the homozygous but in the heterozygous range. Furthermore, we observed no stimulation of CBS activity by S-adenosylmethionine, contrary to a threefold stimulation in control fibroblast extract. The mutation was introduced in an E. coli expression system and CBS activities were measured after addition of different S-adenosylmethionine concentrations (0-200 microM). Again, we observed a defective stimulation of CBS activity by S-adenosylmethionine in the mutated construct, whereas the normal construct showed a threefold stimulation in activity. These data suggest that this D444N mutation interferes in S-adenosylmethionine regulation of CBS. Furthermore, it indicates the importance of S-adenosylmethionine regulation of the transsulfuration pathway in homocysteine homeostasis in humans.

[Bilateral lesions of the basal ganglia as a sign of chronic carbon monoxide intoxication]. / Bilaterale laesies van de basale ganglia als aanwijzing voor een chronische koolmonoxide-intoxicatie.

A 40-year-old, previously healthy man presented with a subacute coordination disorder and intermittent paraesthesias of the right arm that had begun several months before and had disappeared spontaneously within a few weeks. Neurological examination showed a mildly flattened nasolabial fold on the right side and subtle hypertonia of the right arm. A CT-scan of the brain revealed calcifications in the left caudate nucleus and putamen. Cerebral MRI showed markedly enlarged Virchow-Robin spaces bilaterally in the basal ganglia and extensive periventricular white matter lesions. The differential diagnosis of these radiological findings included carbon monoxide intoxication. Ancillary investigations excluded other causes for the radiological abnormalities, and a defective gas stove that produced carbon monoxide was found in the patient's house. Although carbon monoxide poisoning is relatively rare in the Netherlands, it remains important to be alert to the possibility of such exposure. Radiological findings, notably bilateral lesions of the basal ganglia, may point in the direction of the proper diagnosis.

Diagnostic reference frames for seizures: A validation study.

INTRODUCTION: We developed structured descriptions of signs and symptoms for specific seizure types (called Diagnostic Reference Frames-DRFs-by us) that can serve as a frame of reference in the process of classifying patients with epileptic seizures. In this study the validity of the DRFs for clinical use is evaluated and described. MATERIAL AND METHODS: In this study we use a decision support system based on the DRFs and using Bayes's rule for the validation of the DRFs. Patient's manifestations are entered in the decision support system and by successively applying Bayes's rule posterior probabilities are calculated. The DRFs with the highest posterior probability gives an indication of the classification of the seizure. The validation of the DRFs was performed by comparing the seizure type with the highest posterior probability with the classification of experienced epileptologists on a series of test cases with known epileptic seizures. In this way we assessed the accuracy of the DRFs in classifying patients with epileptic seizures. RESULTS: We included sixty-six patients in this efficacy study. The patients and/or their relatives described the manifestations occurring during a seizure. Sixty cases (91%) were correctly classified using the decision support system. DISCUSSION: The accuracy of 91 % indicates that the knowledge encoded in the DRFs for the included seizure types is valid. The next step is to test the DRFs in a clinical setting to evaluate the applicability in daily practice.

Cost-effectiveness of add-on lamotrigine therapy in clinical practice.

OBJECTIVE: This retrospective study addresses the cost-effectiveness of add-on therapy with lamotrigine in clinical practice. METHODS: Two years' observational data of 165 patients were used. Seizure frequency, adverse effects and direct medical costs were recorded for the year before and the year after the start of lamotrigine add-on therapy. Therapy effectiveness was measured by: (1) reduction in seizure frequency and (2) retention time. The incremental cost-effectiveness ratio expressed the direct medical cost per patient treated effectively with lamotrigine. RESULTS: The cost of medication was 492 (95% CI: 399-583) higher after the start of lamotrigine therapy. The extra cost of lamotrigine therapy (622) was partly offset by a reduction of the cost of co-medication (-130; 95% CI: -210 to -50). Overall, the total medical cost was 453 higher in the first year of lamotrigine therapy than in the year before the start of lamotrigine. Lamotrigine was effective in 47% of all the patients, making the resultant incremental cost-effectiveness ratio 954 per year. DISCUSSION: Add-on therapy of lamotrigine for patients with uncontrolled epilepsy offers improved health outcomes. Lamotrigine therapy is associated with increased cost (453) and an annual incremental cost-effectiveness ratio of 954. These data, together with utility data published in the literature, support the notion that lamotrigine should be considered as an add-on therapy in for patients with refractory epilepsy.

Effectiveness of lamotrigine in clinical practice: results of a retrospective population-based study.

OBJECTIVE: Evaluation of the effectiveness of lamotrigine in a population-based cohort of epilepsy patients. METHODS: Medical charts of 360 patients treated in 37 centres in The Netherlands were reviewed. Effectiveness of lamotrigine therapy was assessed during the first year of use, with patients serving as their own controls. Effectiveness was measured by reduction in seizure frequency and retention time. RESULTS: Effectiveness could only be assessed in 165 patients; assessment in remaining patients was not possible due to various reasons, such as insufficient medical chart information. Lamotrigine was effective in 40% of patients who had been prescribed lamotrigine because of insufficient seizure control (n=112), and 14% of these 112 patients became seizure free. Duration of epilepsy, baseline seizure frequency, valproate use, drug load and number of antiepileptic drugs (AED) used were related to effectiveness of lamotrigine. In this group, 36% continued lamotrigine (LTG) throughout the first year without experiencing a >50% seizure reduction. Lamotrigine was effective in 63% of patients who received the drug because of poor tolerability of other antiepileptic drugs (n=53). DISCUSSION: Lamotrigine is an effective drug in clinical practice. Use of retention time measures only may not correctly reflect the efficacy of antiepileptic drugs.

Vagus nerve stimulation in patients with catastrophic childhood epilepsy, a 2-year follow-up study.

PURPOSE: To establish the long-term efficacy and tolerability of vagus nerve stimulation (VNS) in children with a Lennox-like syndrome. METHOD: This study was a longitudinal observational prospective cohort analysis. Baseline: 6 months. FOLLOW-UP: 24 months. Screening (baseline and every 6 months): MRI (baseline only), EEG, neuropsychological evaluation, ECG and blood sampling for antiepileptic drug levels. Nineteen children are included. RESULTS: A seizure frequency reduction of 20.6% was found at the end of the follow-up period. No relationship was detected between the length of the stimulation period and the reduction in the seizure frequency. 21% of the patients showed a reduction in seizure frequency of 50% or more. The seizure severity showed improvement in the first 12 months of treatment. The largest seizure reduction was found in the patients with highest frequency of background activity at the baseline EEG. Neuropsychological findings: no negative impact on behaviour, moderate improvement in function, behaviour and mood. Largest seizure reduction was found in the group with the highest baseline mental function. The scores for mental age improved independently of the seizure control. Twelve patients (63%) experienced minor side effects, which subsided after 1 month. CONCLUSION: (1) There was a significant reduction in seizure frequency and severity. (2) No serious side effects were recorded. (3) No negative effects on cognition or quality of life were apparent. (4) Patients with highest baseline mental functioning showed the highest seizure reduction. (5) Those patients with less disturbed EEG (high background activity and less interictal epileptic activity) showed the highest seizure reduction.

Severe early onset osteopenia and osteoporosis caused by antiepileptic drugs.

We describe two adult patients with epilepsy who received long-term antiepileptic drug therapy, a woman aged 39 years and a man aged 38 years, in whom severe osteopenia and osteoporosis, respectively, were diagnosed. Both had had epilepsy since childhood, both were seizure free and off medication for several years before the epilepsy started again. The female patient first sustained a complicated pelvis fracture after minor trauma. Next, both patients had infractions of several thoracic vertebrae after a generalised tonic-clonic seizure. Dual-energy X-ray absorptiometry for measurement of the bone mineral density revealed osteopenia in both. Bone biopsy was only performed in the male patient and showed moderate osteoporosis. Taking into consideration the young age for osteopenia and osteoporosis and the absence of other underlying causes, the long-term anticonvulsant therapy is the most likely cause of the development of osteopenia and osteoporosis in these patients. Reviewing recent literature data, advice from healthcare organisations and medical guidelines, the authors were surprised by the lack of protocols and preventive measures for patients with epilepsy who have been on antiepileptic drug therapy for many years. With this article we stress the urgent need to develop protocols and guidelines for preventive interventions.

[Epileptic seizures during childbirth in a patient with idiopathic generalised epilepsy]. / Epileptische aanvallen in het kraambed bij een patiënte met idiopathische gegeneraliseerde epilepsie.

During her first pregnancy, a 37-year-old woman with idiopathic generalised epilepsy that was adequately controlled with lamotrigine experienced a series of epileptic seizures following an elective caesarean section. The attacks were terminated with diazepam. The following day, she developed EEG-confirmed status epilepticus, for which midazolam was administered intravenously. No further attacks were observed and the patient was later discharged in good condition with a healthy newborn son. She remained on lamotrigine therapy. At the end of her second pregnancy, the patient again experienced tonic-clonic seizures. The dosage of lamotrigine was increased and the patient received clonazepam intravenously, but a new seizure quickly occurred. Following an emergency caesarean section with midazolam treatment, a healthy daughter was born. No further attacks were observed. This case history illustrates the occurrence of adult idiopathic generalised epilepsy and highlights the problems that can arise late in pregnancy and during childbirth.

A de novo missense mutation in a critical domain of the X-linked DDP gene causes the typical deafness-dystonia-optic atrophy syndrome.

We report the first de novo mutation in the DDP gene in a Dutch 11-year-old boy with deafness and dystonia. Previously reported mutations in the DDP gene have all been frameshifts/nonsense mutations or deletion of the entire gene as part of a larger deletion encompassing the BTK gene. The clinical presentation was uniformly characterised by sensorineural hearing loss, dystonia, mental deterioration, paranoid psychotic features, and optic atrophy, indicating progressive neurodegeneration. Our report illustrates that de novo mutations occur and that a missense mutation, C66W, may cause an equally severe clinical picture. The diagnosis of sensorineural hearing impairment associated with neurologic and visual disability in a male, therefore, should encourage the search for mutations in the DDP gene, even in sporadic cases. The association of deafness-dystonia syndrome with a missense mutation provides valuable information for in vitro investigations of the functional properties of the deafness-dystonia peptide which was recently shown to be the human homolog of a yeast protein, Tim8p, belonging to a family of small Tim proteins involved in intermembrane protein transport in mitochondria.

Mitochondrial encephalomyopathy. Association with an NADH dehydrogenase deficiency.

A 17-year-old patient had a progressive hypokinetic-rigid syndrome and several other signs and symptoms that indicated central nervous system involvement. Biochemical studies revealed a reduced form of nicotinamide-adenine dinucleotide dehydrogenase deficiency in skeletal muscle. Clinical signs and symptoms, and their association with an established defect of energy metabolism, led us to classify this disorder as a mitochondrial encephalomyopathy of Leigh's type.

Successful treatment of pure myopathy, associated with complex I deficiency, with riboflavin and carnitine.

We describe a 6-year-old boy who presented with progressive muscle weakness. Additional investigations revealed the existence of a myopathy and a pure motor neuropathy. Biochemical studies in muscle tissue showed a defect of NADH dehydrogenase (complex I). The patient dramatically improved on treatment with riboflavin and L-carnitine. Seven months after the start of the treatment, complex I activity was determined again and appeared to be normalized. Normalization of the enzymatic defect at this level has not been reported before. We provide a survey of nine patients with pure myopathy, associated with complex I deficiency and onset of symptoms in childhood.

Progressive infantile poliodystrophy. Association with disturbed pyruvate oxidation in muscle and liver.

Progressive infantile poliodystrophy (Alpers' disease) is associated with abnormalities in pyruvate metabolism or in cell mitochondria. A 3-year-old-boy had a severe and rapidly progressive neurologic disorder characterized by psycho-motor retardation, tetraparesis, ataxia, and myoclonic jerks, the illness being exacerbated during periods of infection. Lactate concentration in CSF was elevated. Histopathologic studies revealed lipid storage in liver and muscle. Autopsy showed a progressive infantile poliodystrophy. Mitochondrial abnormalities were found in heart muscle. Biochemical studies of muscle and liver tissue suggested a disturbance in nicotinamide adenine dinucleotide (reduced form) oxidation.

Lafora's disease. Comparison of inclusion bodies in skin and in brain.

A patient had the clinical and neuropathologic signs of Lafora's disease. Skin biopsy specimens from the midcalf area confirmed earlier findings by showing numerous periodic acid-Schiff-positive inclusion bodies in eccrine sweat gland duct cells. In our patient, however, inclusion bodies were more abundantly present in the apocrine sweat gland duct cells of the axilla skin. In brain biopsy specimens and autopsy material the same periodic acid-Schiff-positive inclusion bodies were found. From these data it can be stated that skin biopsy of the axilla is the method of first choice in confirming the diagnosis.

Use of antiepileptic drugs in a community-dwelling Dutch population.

We compared the treatment policy for patients with epilepsy in six Dutch cities, comprising 302, 149 inhabitants, with the treatment policies of a secondary referral center (a university hospital) and tertiary referral centers (outpatient departments of epilepsy centers). By comparing the prevalence of individuals receiving antiepileptic drugs in the six cities with the epidemiologic data for epilepsy in Rochester, Minnesota, we concluded that prescription data offer a suitable means by which to estimate the prevalence of epilepsy in a community. To compare prescriptions in cases of polytherapy, we normalized data by using defined daily doses published by the WHO Collaborating Center for Drugs Statistics Methodology and the Nordic Council on Medicines and concluded that the defined daily doses of antiepileptic drugs should be further elaborated. There is a need to obtain complete dose-response curves of equivalent antiepileptic drugs in humans. The trend of drugs use found in the six cities, the university hospital, and the epilepsy centers is, however, in accord with the expectations regarding primary, secondary, and tertiary referral centers.

Dystrophic myopathy of the diaphragm in a neonate with severe respiratory failure during infectious episodes.

In this study a boy is described who showed slight postnatal asphyxia related to isolated dystrophic diaphragmatic musculature. Development was complicated by several periods of bronchopneumonia necessitating artificial respiration each time.

Angelman syndrome in adulthood.

We studied the clinical and EEG-findings in 28 adult patients (aged 20-53 years) with Angelman syndrome (AS). Twenty-three showed a maternal chromosome 15q11-13 deletion; in 5, the diagnosis was based on a combination of typical clinical findings. Compared to the clinical manifestations present in childhood, "coarsening" of facial traits (100%), thoracic scoliosis (71%), and being wheelchair-bound (39%) were found more frequently. Paroxysms of laughter were still observed in adulthood (79%), but less frequently than in childhood. Most adult patients could feed themselves, but needed help with many daily activities. The majority (82%) had epileptic seizures. Abnormal EEG-activity consisting of 2-3/s rhythmic triphasic waves of high amplitude with a maximum over the frontal regions, which has been identified in many AS children, was found in 67% of these adult patients.

Angelman syndrome without detectable chromosome 15q11-13 anomaly: clinical study of familial and isolated cases.

The clinical findings in 12 Angelman syndrome (AS) patients (4 sib pairs and 4 sporadic cases, aged 12-55 years) without a cytogenetic or molecular detectable defect at the AS locus were compared to those of 28 AS patients (aged 11-50 years) with a deletion, in order to determine whether the clinical spectrum differed between the two groups. There were only two minor differences, i.e., mandibular prognathism was always found in the patients with a defect (100% vs. 58%), whereas truncal hypotonia was found less frequently in the group with a detectable genetic defect (54% vs. 91%). All other clinical and physical characteristics were equally represented in the two groups. Epileptic seizures occurred in 93% and 75%, respectively, of patients with and without a detectable chromosome 15 defect. Specific EEG patterns were found in 90% of both groups. The clinical signs and symptoms of our patients closely resemble those in familial AS cases reported in the literature, with the exception of scoliosis, which was present in 55% of the patients in our study. We conclude that the absence of a detectable cytogenetic or molecular defect at the AS locus is not associated with a strikingly different AS phenotype, compared to those with such a defect. Mutation analysis of the UBE3A gene in our patients without a detectable genetic defect, especially in the familial cases, is currently underway.

Subacute sclerosing panencephalitis in The Netherlands--1976-1990.

Since 1976, when general immunization against measles was introduced in the Netherlands, all new cases of subacute sclerosing panencephalitis (SSPE) were registered and detailed data about immunization, epidemiology and disease progression were collected on them. Up to 1991, 99 new patients have been registered of which 81 were born in this country and 18 elsewhere. From 1981 onwards, the incidence of SSPE among those born in the Netherlands decreased gradually from 13 cases per year to one case per year. This decrease is attributed to the large scale of immunization against measles. Three SSPE patients had been immunized against measles, all of them without a history of clinical measles. Epidemiology and risk factors of SSPE did not differ from those reported in other countries. An exceptional cluster of four patients in one town, who had measles in the same year, is reported. Progression of SSPE appeared to be age related. A total of 28 patients was treated with Inosiplex; no significant effect on survival in stage 3 of the disease was found.

Selection criteria for the clinical use of the newer antiepileptic drugs.

In recent years, several new antiepileptic drugs (AEDs) have been licensed: felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, vigabatrin and zonisamide. These drugs have proven efficacy as add-on therapy in patients with difficult-to-treat partial epilepsy, as 20-50% of patients treated in add-on trials experienced a seizure reduction of >or=50%. Relatively few trials have been conducted to evaluate these drugs as monotherapy for patients with newly diagnosed epilepsy. In the monotherapy trials that have been conducted, the newer drugs were often as efficacious as conventional drugs, and their tolerability was often better. However, the methodology of these trials can be criticised. Because of the relative lack of robust data for the newer agents, the conventional drugs have thus far maintained their status as first-line monotherapy. However, when first-line monotherapy fails, an alternative drug has to be chosen from the available conventional and newer drugs. This article aims to give detailed background information on the newer AEDs in order to enable physicians to make a rational choice from the available drugs for individual patients. Data are provided for the different newer AEDs on mechanisms of action; efficacy in refractory partial epilepsy, newly diagnosed epilepsy in adults and generalised seizure types; adverse effects; pharmacokinetics; and use in special patient categories.