Mutluay Arslan

De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy.

Epileptic encephalopathies are a phenotypically and genetically heterogeneous group of severe epilepsies accompanied by intellectual disability and other neurodevelopmental features. Using next-generation sequencing, we identified four different de novo mutations in KCNA2, encoding the potassium channel KV1.2, in six isolated patients with epileptic encephalopathy (one mutation recurred three times independently). Four individuals presented with febrile and multiple afebrile, often focal seizure types, multifocal epileptiform discharges strongly activated by sleep, mild to moderate intellectual disability, delayed speech development and sometimes ataxia. Functional studies of the two mutations associated with this phenotype showed almost complete loss of function with a dominant-negative effect. Two further individuals presented with a different and more severe epileptic encephalopathy phenotype. They carried mutations inducing a drastic gain-of-function effect leading to permanently open channels. These results establish KCNA2 as a new gene involved in human neurodevelopmental disorders through two different mechanisms, predicting either hyperexcitability or electrical silencing of KV1.2-expressing neurons.

The effects of biotin supplementation on serum and liver tissue biotinidase enzyme activity and alopecia in rats which were administrated to valproic acid

Valproic acid (VPA) is a widely used and well-tolerable antiepileptic drug in epileptic patients. However, VPA has many side effects dose-dependent or non-dose-dependent. It is reported that VPA treatment may lead to biotin deficiency and low serum and liver tissue biotinidase enzyme activity (BEA). Major clinical manifestations in biotin deficiency are seborrheic dermatitis, dry skin, fine and brittle hair, and alopecia. We aimed to investigate the effects of biotin supplementation on serum and liver tissue BEA and alopecia during VPA therapy. Rats were randomly divided into 4 groups, each consisted of 15 rats (VPA-B1, VPA-B2, VPA, and control). Except the control group, all groups were administrated VPA dose of 600 mg/kg/d per oral (PO) for 60 days with 12h intervals two divided doses. VPA-B1 was administrated biotin dose of 6 mg/kg/d and VPA-B2 was administrated biotin dose of 0.6 mg/kg/d. In the third week of the study, we determined alopecia in the study groups. Alopecia was seen in the subjects of 13.3% of VPA-B1 (n=2), 13.3% of VPA-B2 (n=2), and 40% of VPA (n=6). But statistical significant effect on alopecia by biotin supplementation was not able to be determined between the study groups. In the control group, alopecia was not observed. The ratios of alopecia in the study groups were statistically higher than the control group (p=0.028). Itchiness was more obvious in the study groups compared with the control group. Serum biotin levels of the biotin supplemented groups (VPA-B1 and VPA-B2) were higher than the other groups (VPA and control group). Serum biotin levels of the VPA group were lower than the control group. There were significant decreases in the levels of serum and liver tissue BEA of the study groups compared with the control group. In conclusion we showed that VPA usage reduced the serum and liver tissue BEA and impaired the biotin utilization by affecting the liver. Partial biotinidase deficiency may lead to alopecia. It might be prevented by biotin supplementation in the patients receiving VPA therapy. We considered that further studies are necessary to find out the effective and safe biotin dose.

Clinical spectrum and genotype-phenotype associations of KCNA2-related encephalopathies

&NA; Recently, de novo mutations in the gene KCNA2, causing either a dominant‐negative loss‐of‐function or a gain‐of‐function of the voltage‐gated K+ channel Kv1.2, were described to cause a new molecular entity within the epileptic encephalopathies. Here, we report a cohort of 23 patients (eight previously described) with epileptic encephalopathy carrying either novel or known KCNA2 mutations, with the aim to detail the clinical phenotype associated with each of them, to characterize the functional effects of the newly identified mutations, and to assess genotype‐phenotype associations. We identified five novel and confirmed six known mutations, three of which recurred in three, five and seven patients, respectively. Ten mutations were missense and one was a truncation mutation; de novo occurrence could be shown in 20 patients. Functional studies using a Xenopus oocyte two‐microelectrode voltage clamp system revealed mutations with only loss‐of‐function effects (mostly dominant‐negative current amplitude reduction) in eight patients or only gain‐of‐function effects (hyperpolarizing shift of voltage‐dependent activation, increased amplitude) in nine patients. In six patients, the gain‐of‐function was diminished by an additional loss‐of‐function (gain‐and loss‐of‐function) due to a hyperpolarizing shift of voltage‐dependent activation combined with either decreased amplitudes or an additional hyperpolarizing shift of the inactivation curve. These electrophysiological findings correlated with distinct phenotypic features. The main differences were (i) predominant focal (loss‐of‐function) versus generalized (gain‐of‐function) seizures and corresponding epileptic discharges with prominent sleep activation in most cases with loss‐of‐function mutations; (ii) more severe epilepsy, developmental problems and ataxia, and atrophy of the cerebellum or even the whole brain in about half of the patients with gain‐of‐function mutations; and (iii) most severe early‐onset phenotypes, occasionally with neonatal onset epilepsy and developmental impairment, as well as generalized and focal seizures and EEG abnormalities for patients with gain‐ and loss‐of‐function mutations. Our study thus indicates well represented genotype‐phenotype associations between three subgroups of patients with KCNA2 encephalopathy according to the electrophysiological features of the mutations.

Wider neck circumference is related to severe asthma in children

Obesity is an established risk factor for asthma in children. Measures of central obesity are reported to be more associated with the severity of asthma in adults. The aim of the study was to investigate the association between fat distribution, which is determined by anthropometric measures including neck circumference (NC) and asthma severity in children.

Brachydactyly mental retardation syndrome in differential diagnosis of pseudopseudohypoparathyroidism

Abstract Patients with Albright hereditary osteodystrophy (AHO) phenotype are usually seen in pediatric endocrinology policlinics when they are evaluated for short stature and/or obesity. Brachydactyly mental retardation syndrome (BDMR, OMIM #600430) is a rare genetic disorder caused by aberrations of chromosomal region 2q37 and characterized with AHO-like phenotype without any hormone resistance. Diagnosis of BDMR is based on the detection of the deletion on the long arm of chromosome 2. Diagnosis can usually be made with karyotype analysis but sometimes chromosomal deletion can only be detected by fluorescent in situ hybridization (FISH) screening. We report a patient with the AHO phenotype whose karyotype was normal but who was diagnosed with BDMR with FISH analysis showing 2q deletion. In pediatric endocrinology practice, in patients with AHO phenotype but without parathormone (PTH) resistance, BDMR should be considered. For the diagnosis of BDMR, the subtelomeric region of chromosome 2 should be screened for deletion by FISH analysis even in patients with normal karyotypes.

Association of wider neck circumference and asthma in obese children

BACKGROUND Obesity is a well-established risk factor for asthma. Previous studies have reported that central obesity is associated with asthma. OBJECTIVE To investigate the association between fat distribution, which is determined by anthropometric measures, including neck circumference (NC), and asthma in school-aged children. METHODS Children diagnosed as having asthma were enrolled along with controls who were admitted to our outpatient department with allergic symptoms, such as rhinitis, urticaria and atopic dermatitis. Anthropometric measures, including height, weight, NC, waist circumference, and hip circumference, were obtained. Skin prick tests, blood eosinophil counts, and serum total IgE level measurements were performed. RESULTS A total of 196 children (92 male [46.9%]) were included. Asthma was present in 102 patients (52.1%). Ninety-one of the patients (46.4%) were overweight, and 45 patients (22.9%) were obese. The NC of children with asthma was significantly higher than that of children in the control group. Grades defined according to NC percentiles were also significantly different between groups. In children with asthma, the prevalence of children with an NC higher than the 90th percentile (grade 6) was more frequent when compared with controls. The median NC of obese-overweight children with asthma was significantly higher compared with obese-overweight controls without asthma. Results of multivariable logistic regression analysis revealed that the presence of an NC in the greater than 90th percentile was associated with asthma in obese-overweight children. CONCLUSION This study found that NC, which is a simple anthropometric measure, is associated with asthma in obese children.

SCN1A gene sequencing in 46 Turkish epilepsy patients disclosed 12 novel mutations

PURPOSE The SCN1A gene is one of the most commonly mutated human epilepsy genes associated with a spectrum of phenotypes with variable degrees of severity. Despite over 1200 distinct mutations reported, it is still hard to draw clear genotype-phenotype relationships, since genetic and environmental modifiers contribute to the development of a particular disease caused by an SCN1A mutation. We aimed to initiate mutational screening of the SCN1A gene in Turkey and advance further our understanding of the relationship between the SCN1A sequence alterations and disease phenotypes such as GEFS+, DS and related epileptic encephalopathies. METHODS Mutational analysis of the SCN1A gene was carried out in 46 patients with DS, late-onset DS, GEFS+ and unspecified EE using either direct Sanger sequencing of the coding regions and exon/intron boundaries or massively parallel sequencing. RESULTS Nineteen point mutations, 12 of which were novel were identified, confirming the clinical diagnosis of the patients. Patients with a mutation (either truncating or missense) on linker regions had significantly later disease onset than patients with mutations in homology regions. The presence of SCN1A mutations in two clinically unclassified patients supported the association of SCN1A mutations with a wide range of phenotypes. CONCLUSION The conventional Sanger sequencing method was successfully initiated for the detection of SCN1A point mutations in Turkey in epilepsy patients. Furthermore, a modified strategy of massively parallel pyro-sequencing was also established as a rapid and effective mutation detection method for large genes as SCN1A.

Association of nerve conduction impairment and insulin resistance in children with obesity.

AimThe objective of our study was to investigate nerve conduction in normoglycemic obese children.MethodsA total of 60 children with obesity (30 female and 30 male) and 30 healthy children (15 female and 15 male) were enrolled in the study. Insulin resistance (IR) and other metabolic disturbances were investigated and nerve conduction was measured in all participants. Obese children were divided into groups according to the presence of IR. All results were compared between these subgroups.ResultsThe nerve conduction velocity (NCV) of motor median nerves in the IR+ group was significantly higher than that in the IR− group and lower than that in the control group. The NCV of the motor peroneal nerve in the IR+ group was significantly lower than that in the IR− group. The sensory nerve action potential (SNAP) of the sensory median nerve was significantly lower in the IR+ group compared to that in the IR− group. The sensory sural nerve’s SNAP was significantly lower in the IR+ group than that in the control group.ConclusionNerve conduction tests may help to detect early pathologies in peripheral nerves and to decrease morbidities in obese children.

Visual and brainstem auditory evoked potentials in children with obesity

AIMS The aim of our study is to investigate alterations in visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) in children with obesity. METHODS A total of 96 children, with a mean age of 12.1±2.0 years (range 9-17 years, 63 obese and 33 age and sex-matched control subjects) were included in the study. Laboratory tests were performed to detect insulin resistance (IR) and dyslipidemia. The latencies and amplitudes of VEP and BAEP were measured in healthy and obese subjects. RESULTS The VEP P100, BAEP interpeak latency (IPL) I-III and IPL I-V averages of obese children were significantly longer than the control subjects. When the obese group was divided into two subgroups, those with IR and without IR, BAEP wave I, wave III and P100 wave latencies were found to be longer in the group with IR. A statistically significant correlation was observed between BAEP wave I latency, IPL I-V, IPL I-III and the homeostatic model assessment insulin resistance (HOMA IR) index and fasting insulin level. CONCLUSIONS Our findings suggest that VEP and BAEP can be used to determine early subclinical on auditory and visual functions of obese children with insulin resistance.

Acquired epileptiform opercular syndrome: F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings and efficacy of levetiracetam therapy

We report a five-year-old girl presenting with dysphagia, dysarthria, drooling, and generalized tonic convulsions in whom the final diagnosis was acquired epileptiform opercular syndrome. Levetiracetam monotherapy at a dosage of 40 mg/kg/day improved the clinical findings, and seizures were controlled at the end of the first month of treatment. Six months after the initial diagnosis, she presented with speech deterioration and dysarthria. At this time, although sleep and awake electroencephalography (EEG) were normal, FDG-PET showed hypometabolic and hypermetabolic regions in the anterior/inferior and anterior regions of the right frontal lobe, respectively. By increasing before levetiracetam dosage to 50 mg/kg/day, the clinical findings resolved and the patient is still seizure free. Acquired epileptiform opercular syndrome is a rare epileptic disorder in which the seizures are resistant to conventional antiepileptic drugs. Levetiracetam may be an effective antiepileptic drug in controlling seizures and other clinical findings in acquired opercular epileptiform syndrome. Hypometabolic and hypermetabolic regions in FDG-PET study may be due to ongoing seizure activity or impaired glucose metabolism in this disorder.