De novo SCN1A mutations in migrating partial seizures of infancy.

OBJECTIVE: To determine the genetic etiology of the severe early infantile onset syndrome of malignant migrating partial seizures of infancy (MPSI). METHODS: Fifteen unrelated children with MPSI were screened for mutations in genes associated with infantile epileptic encephalopathies: SCN1A, CDKL5, STXBP1, PCDH19, and POLG. Microarray studies were performed to identify copy number variations. RESULTS: One patient had a de novo SCN1A missense mutation p.R862G that affects the voltage sensor segment of SCN1A. A second patient had a de novo 11.06 Mb deletion of chromosome 2q24.2q31.1 encompassing more than 40 genes that included SCN1A. Screening of CDKL5 (13/15 patients), STXBP1 (13/15), PCDH19 (9/11 females), and the 3 common European mutations of POLG (11/15) was negative. Pathogenic copy number variations were not detected in 11/12 cases. CONCLUSION: Epilepsies associated with SCN1A mutations range in severity from febrile seizures to severe epileptic encephalopathies including Dravet syndrome and severe infantile multifocal epilepsy. MPSI is now the most severe SCN1A phenotype described to date. While not a common cause of MPSI, SCN1A screening should now be considered in patients with this devastating epileptic encephalopathy.

Comorbidities in pediatric epilepsy: beyond "just'' treating the seizures.

The goal of this review is to discuss the comorbidities reported in specific epilepsy syndromes to examine possible underlying causes or associations and to present data on current therapies for these conditions. Comorbid conditions including cognitive impairment, neuropsychiatric problems, and social difficulties are common in children with epilepsy, and often more disabling than the seizures themselves. Biological factors associated with a greater risk of comorbidity in epilepsy include younger age at seizure onset, cognitive impairment, temporal or frontal lobe onset, and intractability. Social factors correlating with greater risk include lower socioeconomic status, lower parental education level, and poorer family function. These comorbid conditions not only have a significant impact on the child but also are a source of increased stress and burden for families. Increased awareness and early diagnosis of these conditions may affect therapeutic intervention and long-term outcome as well as assist in better understanding of potential risk factors and biological mechanisms.

Areal and volumetric bone mineral density changes after renal transplantation in children: a longitudinal study.

INTRODUCTION: The effect of renal transplantation on areal bone mineral density (aBMD) in children has previously been studied. However, most previous reports did not include estimation of volumetric bone mineral density (vBMD) or analyze longitudinal data in these patients. In addition, updated reference standards for aBMD in children have recently been made available. METHODS: This retrospective study describes the longitudinal effect of renal transplantation on aBMD and vBMD in a cohort of 40 pediatric kidney transplant recipients. Lumbar spine aBMD measurements were obtained using dual-energy X-ray absorptiometry prior to transplant and yearly thereafter. vBMD values and z-scores were estimated as described in the most recently published references. RESULTS: A significant decrease in average aBMD and vBMD z-scores was observed within 1 year posttransplant, which did not recover during follow-up. The negative effect of transplantation on vBMD was blunted and vBMD z-scores were higher compared to aBMD. Linear mixed-effects model analysis demonstrated that lumbar spine aBMD and vBMD z-scores were inversely related to yearly prednisone dose (g/m2) but this effect was diminished as glomerular filtration rate was increased. CONCLUSIONS: Bone mineral density was negatively affected by renal transplantation in this cohort of pediatric patients. Estimation of vBMD appears to be appropriate for interpretation of the BMD changes occurring after renal transplant in children. The inverse relation between BMD z-scores and yearly prednisone dose suggests that ongoing posttransplant corticosteroid therapy may be responsible for the negative effect of transplantation on bone mineral density in this cohort.

Acute glomerulonephritis presenting with PRES: a report of 4 cases.

OBJECTIVE: Posterior reversible encephalopathy syndrome (PRES) occurs most commonly in the setting of known hypertension or use of immunosuppressive agents. DESIGN AND METHODS: We report four previously-well children who presented acutely with altered mentation, seizures and visual disturbances and were diagnosed with PRES. RESULTS: Only one child had a history of gross hematuria prior to the seizure. All four were discovered to be hypertensive only after onset of their neurological symptoms, and were subsequently diagnosed with glomerulonephritis. All four had rapid resolution of neurological symptoms with adequate treatment of hypertension. CONCLUSIONS: Blood pressure must be measured promptly in all children presenting with these symptoms. If elevated, the diagnosis of PRES should be strongly considered and a workup for renal disease pursued.

Diagnostic inaccuracy in children referred with "first seizure": role for a first seizure clinic.

PURPOSE: To determine (a) the range of diagnoses, and (b) the prevalence of previous seizures in children presenting to a first seizure clinic. METHODS: One hundred twenty-seven children were seen in a tertiary care First Seizure Clinic. Inclusion criteria were age 1 month-17 years with an unprovoked event suggestive of seizure. Data collected included referring physician specialty, child's age, gender, developmental status, and clinical diagnosis of epileptologist (nonepileptic vs. epileptic). For those with epileptic events, seizure type, syndrome (if identifiable), presumed etiology (idiopathic, cryptogenic, and symptomatic), presence of prior afebrile and febrile seizures, provoking factors, family history, pre/perinatal complications and EEG results were recorded. RESULTS: The diagnosis was epileptic in 94 (74%), nonepileptic in 31 (24%) and unclassifiable in two (2%). Pediatricians were more likely to refer true epileptic events (92%) than ED physicians (76%) or family physicians (65%). Mean age at presentation was 8 years. Fifteen percent of children were developmentally delayed and neurological examination was abnormal in 11%. For those diagnosed with epileptic events, 32 presented with generalized while 62 presented with partial onset seizures. An epilepsy syndrome was identifiable in 15 cases. Thirty-eight percent experienced a prior probable seizure which was recognized by the referring physician in only one case. An EEG was done in all children with seizures and was abnormal in 41%. Early EEG was performed in 20% of children and did not show statistical significance. CONCLUSIONS: Diagnostic inaccuracy is common in first seizure. One quarter of children were incorrectly diagnosed as having a seizure while the diagnosis of epilepsy was missed in over one-third of children.

Factors associated with behavioral and cognitive abnormalities in children receiving topiramate.

The objective of this study was to examine the factors associated with the occurrence of behavioral and cognitive abnormalities in children treated with topiramate. A retrospective chart review of patients up to 18 years of age who had been treated with topiramate at a tertiary epilepsy center was performed. Behavioral or cognitive abnormalities were observed in 11 (14.6%) of 75 children between 2 weeks and 4 months after initiation of therapy. The mean dosage (4.6 mg/kg daily) at which these abnormalities were observed was similar to the mean final dose (5.8 mg/kg daily) in children without abnormalities. The mean rate of dosage increase was 0.72 mg/kg weekly and 0.7 mg/kg weekly in those with and without abnormalities, respectively. Five of the 11 children with behavioral or cognitive abnormalities had a previous history of behavioral or cognitive abnormalities, but only nine of the 64 children without abnormalities had a previous history of behavioral or cognitive abnormalities (P = 0.03). Lamotrigine was used concurrently in four of the 11 children with behavioral or cognitive abnormalities but in only seven of the 64 children without abnormalities (P = 0.05). Behavioral and cognitive abnormalities in children treated with topiramate do not appear to be related to the rate of dosage increase. A previous history of behavioral problems and the concurrent use of lamotrigine may be predisposing factors.

Renal function in Inuit survivors of epidemic hemolytic-uremic syndrome.

We undertook a case-control study to evaluate the renal health of survivors of hemolytic-uremic syndrome (HUS) from the 1991 Arctic epidemic of Escherichia coli O157:H7 gastroenteritis 4 years after the epidemic. Eighteen children who developed HUS during the 1991 epidemic and 18 age- and sex-matched controls from the same community who had uncomplicated gastroenteritis were compared in 1995 for height, weight, blood pressure, urinalysis, and glomerular filtration rate (GFR), measured using continuous subcutaneous infusion of non-radioactive iothalamate. HUS survivors did not differ from controls in height, weight, systolic (HUS 118 mmHg, control 117 mmHg) or diastolic (HUS 64 mmHg, control 62 mmHg) blood pressures. Hematuria was detected more frequently in HUS survivors (11/18 vs. 4/18, P<0.05), but no child had proteinuria. Mean GFR did not differ between the two groups (HUS 159 ml/min per 1.73 m2, control 147 ml/min per 1.73 m2). Survivors of post-enteritic HUS from the 1991 Arctic E. coli 0157:H7 outbreak have excellent renal function 4 years after the epidemic.