Candan Gürses

Pathophysiological Mechanisms of Dominant and Recessive GLRA1 Mutations in Hyperekplexia

Hyperekplexia is a rare, but potentially fatal, neuromotor disorder characterized by exaggerated startle reflexes and hypertonia in response to sudden, unexpected auditory or tactile stimuli. This disorder is primarily caused by inherited mutations in the genes encoding the glycine receptor (GlyR) α1 subunit (GLRA1) and the presynaptic glycine transporter GlyT2 (SLC6A5). In this study, systematic DNA sequencing of GLRA1 in 88 new unrelated human hyperekplexia patients revealed 19 sequence variants in 30 index cases, of which 21 cases were inherited in recessive or compound heterozygote modes. This indicates that recessive hyperekplexia is far more prevalent than previous estimates. From the 19 GLRA1 sequence variants, we have investigated the functional effects of 11 novel and 2 recurrent mutations. The expression levels and functional properties of these hyperekplexia mutants were analyzed using a high-content imaging system and patch-clamp electrophysiology. When expressed in HEK293 cells, either as homomeric α1 or heteromeric α1β GlyRs, subcellular localization defects were the major mechanism underlying recessive mutations. However, mutants without trafficking defects typically showed alterations in the glycine sensitivity suggestive of disrupted receptor function. This study also reports the first hyperekplexia mutation associated with a GlyR leak conductance, suggesting tonic channel opening as a new mechanism in neuronal ligand-gated ion channels.

Subacute sclerosing panencephalitis: clinical and magnetic resonance imaging evaluation of 36 patients.

We studied 36 patients (24 males, 12 females), all of whom had definite subacute sclerosing panencephalitis with typical periodic complexes in their electroencephalograms and increased titers of measles antibody in serum and cerebrospinal fluid. Their clinical and laboratory findings on admission were reviewed retrospectively. The age at onset of symptoms varied from 4 to 23 years. The average age at onset of disease was 13.1 ± 4.18 years. The mean of the duration from the infection to the onset of subacute sclerosing panencephalitis was 9 years. Unusual symptoms, especially in the early periods of disease, included hemiparesis (7 patients), headache (3), generalized tonic-clonic seizures (6), absence seizure (1), nausea (3), and vomiting (3). Twenty-six cranial magnetic resonance imaging (MRI) and 12 computed tomography examinations were performed. Nine patients had normal MRI. In the early stages, lesions usually involved parieto-occipital corticosubcortical regions asymmetrically. In time, symmetric periventricular white-matter changes became more prominent. In addition to the common clinical findings in cases of subacute sclerosing panencephalitis reported in the literature, there were some different clinical features of the disease. Eventually, we concluded that there seems to be no correlation between the clinical stages and either the duration from the onset of subacute sclerosing panencephalitis or the MRI findings. (J Child Neurol 2002;17:25-29).

Hot Water Epilepsy: Clinical and Electrophysiologic Findings Based on 21 Cases

Summary:  Purpose: Our aim is to outline the clinical and electroencephalographic (EEG) features of patients with hot water epilepsy (HWE), a rare and unique form of reflex epilepsy.

Myoclonic seizures subside in the fourth decade in juvenile myoclonic epilepsy

Objective: Our aim was to assess the long-term follow-up of juvenile myoclonic epilepsy (JME), with an emphasis on the course of the myoclonic seizures. Methods: We enrolled 48 patients with JME (29 F, 19 M; aged 39.9 ± 9.5 years) followed up for a mean of 19.6 ± 5.7 years. The remission for 5 years and relapses were evaluated for all seizure types and the changes in severity/frequency of myoclonia were systematically questioned. The clinical and EEG features, antiepileptic drug (AED) treatment regimen, and systemic and psychiatric comorbid diseases were evaluated. Results: We found a benign course in 66.6% whereas 16.7% had pseudo-resistance due to problems in treatment or lifestyle. The true-resistant course observed in the remaining 16.7% was significantly associated with psychiatric disorders and the presence of thyroid diseases. In 54.2% of the patients, myoclonia were in remission for a mean duration of 8.4 ± 7.7 years, after an average age of 32.9 ± 9.6. Of these patients, 6 were on a lower dose of AED in comparison to the dosage needed to control the seizures in the beginning, and 5 patients had stopped AED treatment. None of the latter 11 patients except one relapsed during the follow-up. Furthermore, 21 other patients (43.8%) described substantial alleviation after age 31.3 ± 8.4 in the severity of myoclonia. Conclusion: Although a great majority of the patients with juvenile myoclonic epilepsy had continuing seizures after a follow-up of 20 years, almost all had either 5-year remission or a substantial alleviation of the myoclonic seizures.

Periodic lateralized epileptiform discharges: association with seizures

The clinical features and EEGs of 45 consecutive patients (40 adults and 5 children) who had periodic lateralized epileptiform discharges (PLEDs) were reviewed to determine the relationship between seizures and PLEDs. Focal encephalitis and ischemic stroke were the most frequent underlying processes for adult patients. All of the children, but only six of the adults, had long-lasting cerebral disorders whereas the remaining adults had acute or subacute illness. There were 38 patients (84.4%) experiencing a seizure disorder. Twenty-six of them had their first seizure during their acute illness, as the pattern of PLED was encountered. Eight cases had status epilepticus, and seven of them had epilepsia partialis continua. Nineteen patients had a recent seizure in the day when PLEDs were observed but not during EEG recording; 12 patients had their seizures within 10 days before the observation of PLED. PLEDs were grouped into three categories with respect to their extensions: lateralized to one hemisphere (n = 22), localized in one region (n = 17) and being prominent over one side with contralateral spread (n = 6). The last group was found to be more closely associated with frequent seizures or status epilepticus than the other two groups. Our results showed that PLEDs were highly correlated with recent seizures in the majority of the patients. These EEG findings may be considered as a manifestation of an increased neuronal excitability caused by different etiologies; but not an ictal pattern.

Late-onset and Slow-progressing Lafora Disease in Four Siblings with EPM2B Mutation

Summary:  We report a family with four brothers affected by Lafora disease (LD). Mean age at onset was 19.5 years (range, 17–21). In all cases, the initial obvious symptoms were diffuse myoclonus and occasional generalized tonic–clonic seizures (GTCSs), followed by cognitive difficulties. Severity of myoclonus, seizure diaries, and neurologic and neuropsychological status were finally evaluated in March 2005. The duration of follow‐up was >10 years for three subjects. Daily living activities and social interaction were preserved in all cases and, overall, the progression of the disease was slow. Genetic study revealed the homozygous mutation D146N in the EPM2B gene. We suggest that this mutation may be associated with a less severe LD phenotype.

Recurrent absence status epilepticus: clinical and EEG characteristics

In order to outline the clinical and EEG characteristics of recurrent absence status epilepticus (ASE), eight cases with more than two attacks of ASE were studied. Their current ages were between 13 and 84 years, and five of the patients were women. There was a history of epilepsy in five of the patients before the first ASE episode. A varying degree of confusion was the main clinical symptom with associated mild motor signs like perioral, eyelid and generalised myoclonus, seen in one, two and four patients respectively. Two of the patients had juvenile myoclonic epilepsy. One patient had an atypical form of childhood absence epilepsy characterised by recurrent ASE attacks on awakening. There were two patients with phantom absences and late onset generalised convulsions, one patient with perioral myoclonia and absences, and finally two patients with eyelid myoclonia with absences, which are proposed syndromes. On the EEGs that revealed the diagnosis of ASE, there was a marked variability of the generalised multispike and wave discharges. The EEG findings appeared to be syndrome-related with some exceptions. IV Clonazepam lead to a dramatic improvement. Our study shows that the majority of recurrent ASE cases do not fit into the International syndrome classification.

Investigation of neuronal autoantibodies in two different focal epilepsy syndromes

Neuronal antibodies have been identified in patients with seizures as the main or sole symptom. Our aim was to investigate the prevalence of these autoantibodies in patients with focal epilepsy of unknown cause (FEoUC) and in the group having mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE‐HS).

Obsessive–compulsive disorder after epilepsy surgery

It is a well-known fact that after epilepsy surgery (ES) preexisting psychopathology may deteriorate or de novo psychopathological syndromes, mainly of a depressive and psychotic nature, may appear. Previously, recovery of obsessive-compulsive disorder (OCD) after ES has been reported in patients who had comorbid OCD preoperatively; however, there have been no reports on the appearance of de novo OCD interfering with daily living activities post-ES. This is the first report of OCD after ES in patients with mesial temporal lobe epilepsy (MTLE). Five patients with MTLE were identified with obsessive personality traits before surgery. Within the first 2 months after ES, two of these MTLE patients fulfilled OCD diagnostic criteria. These OCD patients were not any different from the other three patients with respect to age, age of onset of epilepsy, seizure types, and seizure frequency. All patients stopped having seizures postoperatively, but the OCD patients had worse quality of life postoperatively than preoperatively. Our findings show that those patients with obsessive traits preoperatively should be carefully monitored after ES.

A comparative study of obsessive–compulsive disorder and other psychiatric comorbidities in patients with temporal lobe epilepsy and idiopathic generalized epilepsy

Our aim was to assess the associations of temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) with comorbid psychiatric conditions, especially obsessive-compulsive disorder (OCD), in a comparative design. We evaluated 29 patients with TLE, 27 patients with IGE, and 30 healthy controls. The Structured Clinical Interview for DSM-IV (SCID), Yale-Brown Obsessive Compulsive Scale (Y-BOCS) Symptom Checklist, and Beck Depression Inventory (BDI) were administered. Among patients with TLE, 75.9%, and among patients with IGE, 48.1% had at least one Axis I psychiatric disorder. Clinically meaningful obsessive-compulsive symptoms (CM-OCS) were noted in 10 patients with TLE and in 3 patients with IGE, and this difference was statistically significant (P<0.05). CM-OCS were present in 9 of 18 patients with left-sided TLE, but in only 1 of 11 patients with right-sided TLE. Higher comorbidity in TLE suggests that involvement of the temporal lobe may play a role in the development of specific psychopathological syndromes.