SUMMARY Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified 5 independent homozygous deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule severing enzyme katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of katanin, and other microtubule associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specifically affects the asymmetrically dividing neuroblasts, which display supernumerary centrosomes and spindle abnormalities during mitosis, leading to cell cycle progression delays and reduced cell numbers. Furthermore, kat80 depletion results in dendritic arborization defects in sensory and motor neurons, affecting neural architecture. Taken together, we provide insight into the mechanisms by which KATNB1 mutations cause human cerebral cortical malformations, demonstrating its fundamental role during brain development.

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In the original Figure 5 legend the 3D projections of Z sections and quantifications of glial cells were mislabeled. This has been corrected in the article online.228 Neuron 85, 228, January 7, 2015 ª2015 Elsevier Inc.

Elemental mercury exposure occurs frequently and is potentially a toxic, particularly in children. Children are often attracted to elemental mercury because of its color, density, and tendency to form beads. Clinical manifestations of elemental mercury intoxication vary depending on its form, concentration, route of ingestion, and the duration of exposure. We present data on 179 pediatric cases of elemental mercury poisoning from exposure to mercury in schools in two different provinces of Turkey. Of all patients, 160 children had both touched/played with the mercury and inhaled its vapors, while 26 children had only inhaled the mercury vapor, two children reported having tasted the mercury. The median duration of exposure was 5 min (min 1-max 100), and 11 (6 %) children were exposed to the mercury for more than 24 h at home. More than half of the children (51.9 %) were asymptomatic at admission. Headache was the most common presenting complaint. The results of physical and neurological examinations were normal in 80 (44.6 %) children. Mid-dilated/dilated pupils were the most common neurological abnormality, and this sign was present in 90 (50.2 %) children. Mercury levels were measured in 24-h urine samples daily, and it was shown that the median urinary level of mercury was 29.80 μg/L (min, 2.40 μg/L; max, 4,687 μg/L). A positive correlation was also found between the duration of exposure and urinary mercury levels (r = 0.23, p = 0.001). All patients were followed up for 6 months. On the first follow-up visit performed 1 month after discharge, the neurological examinations of all patients were normal except for those patients with peripheral neuropathy and visual field defects. On the last follow-up visit at the sixth month, only two children still experienced visual field defects. In conclusion, this study is one of the largest case series of mercury intoxication of students in schools. Elemental mercury exposure can be potentially toxic, and its symptomatology is variable, particularly in children. Therefore, school staff and children should be aware of the risk of mercury toxicity. Pediatricians also need to warn parents and children about the hazards of playing with any chemical.

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Background and aim Occasionally, children with COVID-19 may develop arrhythmia, myocarditis, and cardiogenic shock involving multisystemic inflammatory syndrome in children (MIS-C). This study aimed to identify the laboratory parameters that may predict early cardiovascular involvement in these patients. Materials and methods Data of 320 pediatric patients, aged 0–18 years (average age, 10.46 ± 5.77 years; 156 female), with positive COVID-19 reverse transcription–polymerase chain reaction test and with cardiac biomarkers at the time of admission to the pediatric emergency department were retrospectively scanned. The age, sex, COVID-19-associated symptoms, pro-brain natriuretic peptide (proBNP), CK-MB, and troponin I levels of the patients were recorded. Results Fever was noted in 58.1% of the patients, cough in 29.7%, diarrhea in 7.8%, headache in 14.7%, sore throat in 17.8%, weakness in 17.8%, abdominal pain in 5%, loss of taste in 4.1%, loss of smell in 5.3%, nausea in 3.4%, vomiting in 3.8%, nasal discharge in 4.4%, muscle pain in 5%, and loss of appetite in 3.1%. The proBNP value ≥282 ng/L predicted the development of MIS-C with 100% sensitivity and 93% specificity [AUC: 0.985 (0.959–1), P < 0.001]; CK-MB value ≥2.95 with 80% sensitivity and 77.6% specificity [AUC: 0.792 (0.581–1), P = 0.026]; and troponin I value ≥0.03 with 60% sensitivity and 99.2% specificity [AUC: 0.794 (0.524–1)]. Conclusions Cardiac markers (proBNP and troponin I), especially proBNP, could be used to detect early diagnosis of cardiac involvement and/or MIS-C in pediatric patients with COVID-19 and to predict related morbidity and mortality.

Guillain-Barré syndrome is an acute inflammatory demyelinating neuropathy characterized by progressive symmetric polyradiculoneuritis, predominantly manifested by weakness and areflexia. In this article, we report our findings in 25 children treated with intravenous immunoglobulin and compare them with the remaining 30 children who received supportive care only. Only supportive care was given to 30 children who were not able to receive intravenous gammaglobulin because of shortcomings in intravenous gammaglobulin availability owing to a poor import during those years. Twenty-five patients were treated with intravenous gammaglobulin; they received intravenous gammaglobulin 0.4 g/kg/day for 5 consecutive days. Seventeen of the intravenous gammaglobulin group had received intravenous gammaglobulin within 10 days after the first symptoms, and eight of them had received intravenous gammaglobulin after the first 10 days. The average time elapsed for the symptoms to reach the maximum level was 6.9 (range 4-12) days in patients receiving intravenous gammaglobulin in the first 10 days, and it was significantly shorter than the time elapsed for the supportive care group (6.9 versus 8.8 days, respectively) (P < .05). Admission to the hospital after the first symptom, disability grade, time to improve in disability grade, the period of hospitalization, and mortality were not different in the intravenous gammaglobulin and supportive care groups (P > .05). Our suggestion for intravenous gammaglobulin treatment in Guillain-Barré syndrome is that if the patient has risk factors for respiratory insufficiency, then the treatment should be started. We more confidently carry out the follow-up of these patients after the results of this study. In conclusion, although it has been reported that intravenous gammaglobulin facilitates improvement in the disease and the decrease in mortality in children with Guillain-Barré syndrome, it has been mentioned in some studies that the intravenous gammaglobulin treatment was not better than supportive care, as in our study. However, further studies are essential to determine when intravenous gammaglobulin should be given to patients having which clinical and laboratory findings.