The diagnosis of cerebral palsy in two Danish national registries: a validation study.

AIMS: To determine the quality of prospectively collected data from the highly specialized Danish Cerebral Palsy Follow-up Program (CPOP), and to establish the validity of a reported cerebral palsy (CP) diagnosis in the Danish National Patient Registry (NPR), regularly used as a proxy for neurodevelopmental disorders in epidemiological research. METHODS: We compared data from the two registries on children with registered CP, born in Denmark between 2008 and 2009, with information from medical records verified by two experienced physicians specializing in pediatric neurology. Data accuracy was estimated by completeness, correctness, and reliability. Completeness was calculated as the number of cases with correctly registered CP diagnoses divided by the total number of true CP diagnoses (similar to sensitivity). Correctness was calculated as the number of cases with correct registrations divided by the total number of cases (similar to positive predictive value). Reliability was estimated using kappa statistics. RESULTS: Registered CP diagnoses in the CPOP had high accuracy, with 94% correctness and 91% completeness. Furthermore, most key variables in the CPOP showed excellent reliability, especially variables defining the severity of the condition. In the Danish NPR, only 225 of 348 children with a noted CP diagnosis fulfilled the diagnostic criteria for CP, resulting in 65% correctness. CONCLUSIONS: Danish CPOP data are a valid source for epidemiological research. Conversely, a noted CP diagnosis in the Danish NPR was, at best, correct in only two out of three patients.

Effectiveness and safety of everolimus treatment in patients with tuberous sclerosis complex in real-world clinical practice.

BACKGROUND: The randomised double-blinded placebo-controlled EXIST-1-3 studies have showed everolimus effective with adverse effects reported as acceptable in treatment of symptoms in patients with tuberous sclerosis complex (TSC), although evidence of outcomes in clinical practice remains limited. This study aimed to investigate, in clinical practice, the effectiveness and safety of everolimus for epilepsy, renal angiomyolipoma (rAML), and subependymal giant cell astrocytoma (SEGA) in patients with TSC. RESULTS: The study included 64 patients with TSC (median age: 19, range 0.9-54 years) receiving everolimus treatment (Norway: n = 35; Denmark: n = 29). Among 45 patients with epilepsy, 14 (31%) were responders experiencing ≥ 50% reduction in seizure frequency in the last 3 months of treatment compared with the last 3 months before treatment. Nineteen (42%) patients changed their anti-seizure medications (ASMs). Responders were more common among patients < 18 years (46%) than among patients ≥ 18 years (14%, p = 0.03). In 29 patients with rAML, everolimus reduced (≥ 30% decrease) and stabilized (< 20% increase, ≤ 30% decrease) longest diameter of rAML in 38% and 59%, respectively, after a mean treatment duration of 37 months. SEGA volume was reduced in three patients by 71%, 43%, and 48% after 39, 34, and 82 months. Adverse effects were reported in 61 of 64 patients (95%) after a median treatment duration of 31 months (range 0-106), with oral ulceration/stomatitis (63%) and upper respiratory tract infections (38%) being the most common. The most common laboratory abnormalities were increased cholesterol (41%), anaemia (30%), and leucopoenia (25%). Grade 3-4 adverse effects were reported in 36% of cases, and life-threatening conditions were reported in two patients. Nine patients discontinued everolimus treatment. CONCLUSIONS: Seizure reduction in this study sample was consistent with results from EXIST, but might be lower than expected, given that changes in concomitant ASMs are part of clinical practice. Seizure reduction was associated with younger age. As with EXIST, everolimus reduced or stabilised rAML size in most patients. SEGA volume was reduced in all three patients. Close follow-up is needed for this group, especially for children and patients who may not be able to report adverse effects.

Severe Congenital Heart Defects and Cerebral Palsy.

OBJECTIVE: To report the prevalence of cerebral palsy (CP) in children with severe congenital heart defects (sCHD) and the outcome/severity of the CP. METHODS: Population-based, data linkage study between CP and congenital anomaly registers in Europe and Australia. The EUROCAT definition of severe CHD (sCHD) was used. Linked data from 4 regions in Europe and 2 in Australia were included. All children born in the regions from 1991 through 2009 diagnosed with CP and/or sCHD were included. Linkage was completed locally. Deidentified linked data were pooled for analyses. RESULTS: The study sample included 4989 children with CP and 3684 children with sCHD. The total number of livebirths in the population was 1 734 612. The prevalence of CP was 2.9 per 1000 births (95% CI, 2.8-3.0) and the prevalence of sCHD was 2.1 per 1000 births (95% CI, 2.1-2.2). Of children with sCHD, 1.5% (n = 57) had a diagnosis of CP, of which 35 (61%) children had prenatally or perinatally acquired CP (resulting from a brain injury at ≤28 days of life) and 22 (39%) children had a postneonatal cause (a brain injury between 28 days and 2 years). Children with CP and sCHD more often had unilateral spastic CP and more intellectual impairments than children with CP without congenital anomalies. CONCLUSIONS: In high-income countries, the proportion of children with CP is much higher in children with sCHD than in the background population. The severity of disease in children with CP and sCHD is milder compared with children with CP without congenital anomalies.

Children in Denmark with cerebral palsy rarely complete elementary school.

AIM: To investigate how children with cerebral palsy (CP) perform in the Danish school system and which factors are associated with school performance. METHOD: This was a population-based cohort study including 463 126 children born from 1997 to 2003. Data were extracted from seven national registries. The study encompassed 818 children with CP (483 [59.0%] males, 335 [41.0%] females) and 417 731 without CP (214 535 [51.4%] males, 203 196 [48.6%] females). We evaluated two primary outcomes: not completing 10 years of elementary school, defined as attending fewer than eight final mandatory exams; and grade point averages (GPAs). Mann-Whitney U tests were used to analyse differences in GPAs and logistic regressions were used to calculate odds ratios (ORs). RESULTS: Among children with and without CP, 62.6% and 12.4% did not complete elementary school respectively (OR = 11.85 [10.28-13.66]). Additionally, children with CP who attended all final exams achieved lower overall GPAs than children without CP (6.6 vs 7.3, p = 0.001). In children with CP, comorbidities, maternal education, severity of motor impairments, and intellectual deficits were associated with increased odds of not completing elementary school. Notably, one-third of children with CP with apparent normal intelligence did not complete school, despite special educational measures. INTERPRETATION: Danish children with CP rarely complete elementary school despite initiatives for a more supportive educational system. The complexity of individual needs in children with CP may be challenging for an inclusive school environment. WHAT THIS PAPER ADDS: Children with cerebral palsy (CP) have a high risk of not completing elementary school. Children with CP achieve lower overall grades than children without CP. Motor impairment, comorbidities, and maternal education are associated with poor school performance. Intellectual impairment is the most important predictor of poor school performance.

ATP6V0C variants impair V-ATPase function causing a neurodevelopmental disorder often associated with epilepsy.

The vacuolar H+-ATPase is an enzymatic complex that functions in an ATP-dependent manner to pump protons across membranes and acidify organelles, thereby creating the proton/pH gradient required for membrane trafficking by several different types of transporters. We describe heterozygous point variants in ATP6V0C, encoding the c-subunit in the membrane bound integral domain of the vacuolar H+-ATPase, in 27 patients with neurodevelopmental abnormalities with or without epilepsy. Corpus callosum hypoplasia and cardiac abnormalities were also present in some patients. In silico modelling suggested that the patient variants interfere with the interactions between the ATP6V0C and ATP6V0A subunits during ATP hydrolysis. Consistent with decreased vacuolar H+-ATPase activity, functional analyses conducted in Saccharomyces cerevisiae revealed reduced LysoSensor fluorescence and reduced growth in media containing varying concentrations of CaCl2. Knockdown of ATP6V0C in Drosophila resulted in increased duration of seizure-like behaviour, and the expression of selected patient variants in Caenorhabditis elegans led to reduced growth, motor dysfunction and reduced lifespan. In summary, this study establishes ATP6V0C as an important disease gene, describes the clinical features of the associated neurodevelopmental disorder and provides insight into disease mechanisms.

[Basic and advanced treatment of children and adults with epilepsy].

This review finds that, in children and adults with epilepsy, there are several treatment options. Multiple antiseizure medications are available and in case of drug-resistant epilepsy, a non-pharmacological approach is recommended, including epilepsy surgery, vagus nerve stimulation, or ketogenic diet treatment. The aim of the treatment is to avoid further seizures, but also to avoid negative cognitive, psychological, and social consequences of epilepsy.

Nutrition and preparation of blenderized tube feeding in children and adolescents with neurological impairment: A scoping review.

BACKGROUND: The use of homemade tube feeding formula has become increasingly popular for children requiring enteral nutrition. This project aimed to investigate nutrition and preparation of blenderized tube feeding in the field of children and adolescents with neurological impairment. METHODS: A scoping review was performed using established methodologies. In January 2021, we searched PubMed, Embase, CINAHL Complete, the Cochrane Central Register of Controlled Trials, and gray literature to identify relevant articles. MAJOR FINDINGS: Twenty-two papers were included describing the composition of food items, preparation procedures, and food safety. No randomized controlled trials and only a few prospective studies were included. A broad variety of food items from all food groups and many examples of recipes were presented. Most recipes provided 1.0 kcal/ml but tended to contain less energy and nutrients than expected, which could be due to preparation issues, such as sieving and the high viscosity of the blend. Preparation requires a commercial-grade household blender and diligence to ensure thorough household hygiene for adequate food safety. CONCLUSIONS: This review revealed practical experience in the nutrition and preparation aspects of blenderized tube feeding but minimal empirical evidence. Multiple examples of the composition of food items and preparation procedures for blenderized tube feeding were found, but uncertainty regarding the ideal composition or preparation was also exposed. The future of blenderized tube feeding would benefit from clinically tested recipes that include an evaluation of nutrients, viscosity, and microbial contamination, as well as the effect of the food's appearance and scent on the target group.

Using both electromyography and movement disorder assessment improved the classification of children with dyskinetic cerebral palsy.

AIM: Children with dyskinetic cerebral palsy (CP) are often severely affected and effective treatment is difficult, due to different underlying disease mechanisms. Comprehensive systematic movement disorder evaluations were carried out on patients with this disorder. METHODS: Patients born from 1995 to 2007 were identified from the Danish Cerebral Palsy Register and referrals to the neuropaediatric centre, Rigshospitalet, Copenhagen. They were classified by gross motor function, manual functional ability, communication ability, dystonia and spasticity. Electromyography was carried out on the upper and lower limbs. Magnetic resonance imaging scans were revised, and aetiological searches for underlying genetic disorders were performed. RESULTS: We investigated 25 patients with dyskinetic CP at a mean age of 11.7 years. Dystonia, spasticity and rigidity were found in the upper limbs of 21, four and six children, respectively, and in the lower limbs of 18, 18 and three children. The mean total Burke-Fahn-Marsden score for dystonia was 45.02, and the mean Disability Impairment Scale level was 38% for dystonia and 13% for choreoathetosis. Sustained electromyography activity was observed in 20/25 children. Stretching increased electromyography activity more in children with spasticity. There were 10 re-classifications. CONCLUSION: The children had heterogenic characteristics, and 40% were reclassified after systematic movement disorder evaluation.

Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications.

We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability). Those in Groups 1-3 presented with focal or multifocal seizures (median age of onset: 4 months) and focal epileptiform discharges, whereas the onset of seizures in patients with generalized epilepsy was later (median: 42 months) with generalized epileptiform discharges. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin-insensitive human Nav1.6 channels and whole-cell patch-clamping. Two variants causing developmental and epileptic encephalopathy showed a strong gain-of-function (hyperpolarizing shift of steady-state activation, strongly increased neuronal firing rate) and one variant causing benign familial infantile epilepsy or intermediate epilepsy showed a mild gain-of-function (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (reduced current amplitudes, depolarizing shift of steady-state activation, reduced neuronal firing). Functional effects were known for 170 individuals. All 136 individuals carrying a functionally tested gain-of-function variant had either focal (n = 97, Groups 1-3) or unclassifiable (n = 39) epilepsy, whereas 34 individuals with a loss-of-function variant had either generalized (n = 14), no (n = 11) or unclassifiable (n = 6) epilepsy; only three had developmental and epileptic encephalopathy. Computational modelling in the gain-of-function group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. Gain-of-function variant carriers responded significantly better to sodium channel blockers than to other anti-seizure medications, and the same applied for all individuals in Groups 1-3. In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of loss-of-function variant carriers and the extent of the electrophysiological dysfunction of the gain-of-function variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that sodium channel blockers present a treatment option in SCN8A-related focal epilepsy with onset in the first year of life.

The effect of gestational age on major neurodevelopmental disorders in preterm infants.

BACKGROUND: Preterm infants have an increased risk of neurodevelopmental disorders. We established a direct quantitative comparison of the association between the degree of prematurity and three different neurodevelopmental disorders. METHODS: In this cohort study, we combined data from 995,498 children in the Danish Medical Birth Register, from birth years 1997-2013, with information on cerebral palsy, epilepsy, and special educational needs. We estimated the gestational week-specific prevalence and risk for each of the disorders. RESULTS: The risk ratio of cerebral palsy at gestational weeks 21-24, compared to term birth, was more than ten times higher than for the two other disorders. The prevalence of epilepsy and special educational needs declined almost parallel, with 9.2% (4.6%-13.5%) and 12.5% (11.2%-13.7%), respectively, per week of gestation toward term birth. Cerebral palsy did not decline similarly: from gestational weeks 21-24 until week 29 the prevalence declined insignificantly by 0.6% (-11.1%-11.0%) per week; whereas from week 29 until term, the prevalence declined markedly by 36.7% (25.9%-45.9%) per week. CONCLUSIONS: The prevalence and risk of cerebral palsy are affected differently by the degree of prematurity compared with epilepsy and special educational needs, possibly reflecting important differences in cerebral pathophysiology. IMPACT: For each week of gestation toward term birth, there was a clear log-linear decline in the prevalence of early childhood epilepsy and special educational needs. In contrast, the risk of cerebral palsy was high at the earliest gestational age, and the prevalence did not decline significantly until gestational week 29, from where it declined notably by nearly 40% for each week of gestation until term birth. Our results indicate important differences in the pathophysiological processes that associate preterm birth with these three neurodevelopmental disorders.

Declining prevalence of cerebral palsy in children born at term in Denmark.

AIM: To investigate reasons for the declining prevalence of cerebral palsy (CP) in children born at term in Denmark by evaluating obstetric and neonatal factors associated with CP, and their changes over time. METHOD: In this cohort study, we included 987 495 children (504 600 [51.1%] males and 482 895 [48.9%] females) born after 37 completed gestational weeks during birth years 1997 to 2013. Risk ratios of CP for each factor were calculated with log-binominal regression analyses. Significant factors were evaluated concerning their development in prevalence over time. RESULTS: In the antenatal period, there were significant associations with an increased risk of CP and high maternal body mass index (BMI), smoking during pregnancy, nulliparity, male sex, gestational age, and low birthweight. In the study period, fewer females smoked during pregnancy and fewer children were born post-term, dropping from 22.6% to 11.4% and 9.4% to 2.5% respectively. Conversely, the proportion of females with high BMI increased. Most significant risk factors were found in the neonatal period, with an increase in children with diagnosed birth defects and children admitted to neonatal care. INTERPRETATION: Reasons for the declining prevalence of CP appear to be multifactorial and likely include the decline in maternal smoking and children born post-term along with centralization and advances in neonatal treatment.

Combined Muscle Biopsy and Comprehensive Electrophysiology in General Anesthesia is Valuable in Diagnosis of Neuromuscular Disease in Children.

AIM: The diagnostic workup in patients with delayed motor milestones suspected of having either myopathy or a congenital myasthenic syndrome is complex. Our hypothesis was that performance of a muscle biopsy and neurophysiology including stimulated single-fiber electromyography during an anesthetic procedure, combined with genetic testing has a high diagnostic quality. MATERIALS AND METHODS: Clinical and paraclinical data were retrospectively collected from 24 patients aged from 1 month to 10 years (median: 5.2 years). RESULTS: Neurophysiology examination was performed in all patients and was abnormal in 11 of 24. No patients had findings suggestive of a myasthenic syndrome. Muscle biopsy was performed in 21 of 24 and was normal in 16. Diagnostic findings included nemaline rods, inclusion bodies, fiber size variability, and type-II fiber atrophy. Genetic testing with either a gene panel or exome sequencing was performed in 18 of 24 patients, with pathogenic variants detected in ACTA1, NEB, SELENON, GRIN2B, SCN8A, and COMP genes. CONCLUSION: Results supporting a neuromuscular abnormality were found in 15 of 24. In six patients (25%), we confirmed a genetic diagnosis and 12 had a clinical neuromuscular diagnosis. The study suggests that combined use of neurophysiology and muscle biopsy in cases where genetic testing does not provide a diagnosis can be useful in children with delayed motor milestones and clinical evidence of a neuromuscular disease.

Children with dyskinetic cerebral palsy are severely affected as compared to bilateral spastic cerebral palsy.

AIM: We aimed at describing clinical findings in children with dyskinetic as compared to bilateral spastic cerebral palsy (CP). METHODS: Data were extracted from the Danish nationwide CP register. Participants were born in 1999-2007 and were 5-6 years at ascertainment. RESULTS: The total number of CP cases was 1165 of which 92 had dyskinetic and 540 bilateral spastic CP. Prevalence of dyskinetic CP was 0.16 per 1000 live births. In participants with dyskinetic compared to bilateral spastic CP, there was more frequently an Apgar level less than five at five minutes (22.7% vs. 11.2%) and neonatal seizures (43.5% vs. 28.5%), but less respiratory deficiency, hyperbilirubinaemia and sepsis. Impairment based on gross motor function classification was more severe in dyskinetic CP (level III-V 90.0% vs. 66.0%). In dyskinetic CP, there was a high rate of reduced developmental quotient (68.1%), visual impairment (39.3%) and epilepsy (51.6%). Basal ganglia lesions were more prevalent in dyskinetic compared to bilateral spastic CP (27.7% vs. 12.8%). CONCLUSION: Cases of dyskinetic CP had overlapping clinical features with cases of bilateral spastic CP, but differed significantly in several perinatal risk factors. The children with dyskinetic CP had experienced more peri- or neonatal adverse events, and neurodevelopmental impairment was severe.

Neuronal mechanisms of mutations in SCN8A causing epilepsy or intellectual disability.

Ion channel mutations can cause distinct neuropsychiatric diseases. We first studied the biophysical and neurophysiological consequences of four mutations in the human Na+ channel gene SCN8A causing either mild (E1483K) or severe epilepsy (R1872W), or intellectual disability and autism without epilepsy (R1620L, A1622D). Only combined electrophysiological recordings of transfected wild-type or mutant channels in both neuroblastoma cells and primary cultured neurons revealed clear genotype-phenotype correlations. The E1483K mutation causing mild epilepsy showed no significant biophysical changes, whereas the R1872W mutation causing severe epilepsy induced clear gain-of-function biophysical changes in neuroblastoma cells. However, both mutations increased neuronal firing in primary neuronal cultures. In contrast, the R1620L mutation associated with intellectual disability and autism-but not epilepsy-reduced Na+ current density in neuroblastoma cells and expectedly decreased neuronal firing. Interestingly, for the fourth mutation, A1622D, causing severe intellectual disability and autism without epilepsy, we observed a dramatic slowing of fast inactivation in neuroblastoma cells, which induced a depolarization block in neurons with a reduction of neuronal firing. This latter finding was corroborated by computational modelling. In a second series of experiments, we recorded three more mutations (G1475R, M1760I, G964R, causing intermediate or severe epilepsy, or intellectual disability without epilepsy, respectively) that revealed similar results confirming clear genotype-phenotype relationships. We found intermediate or severe gain-of-function biophysical changes and increases in neuronal firing for the two epilepsy-causing mutations and decreased firing for the loss-of-function mutation causing intellectual disability. We conclude that studies in neurons are crucial to understand disease mechanisms, which here indicate that increased or decreased neuronal firing is responsible for distinct clinical phenotypes.

Unexpected marked seizure improvement in paediatric epilepsy surgery candidates.

PURPOSE: Epilepsy surgery is performed based on the assumption that medical refractory epilepsy will continue. Rarely seizure freedom occurs before surgery is performed, while the patient is being evaluated as an epilepsy surgery candidate. The aim of this study was to describe the number of children withdrawn from an epilepsy surgery programme due to unexpected seizure improvement. METHODS: We retrospectively studied 173 children under 18 years with medical refractory epilepsy referred for epilepsy surgery between 1996 and 2010. Medical records were reviewed in 2012 and 2015. RESULTS: At the first evaluation point in 2012, 13 patients were withdrawn from the epilepsy surgery programme due to unexpected marked improvement. In 2015, 6 of them were still seizure free. They had unexpected seizure freedom due to change in AED treatment (n=3) or after a febrile episode (n=3). The mean number of years they had had seizures was 3.4 years (range 0.6-6.2 years) and the number of seizures at inclusion was 209 per month (range 6-750 per month). The duration of follow-up was 6.6 years after inclusion into the epilepsy surgery programme (range 4.0-13.0 years). The aetiology of the epilepsy for these patients was heterotopia (n=1), focal cortical dysplasia (n=3), infarction (n=1) and unknown, with normal MRI (n=1). They all had an IQ in the normal range. Two of the remaining 7 children were operated later. CONCLUSION: Unexpected seizure control may occur during epilepsy surgery evaluation.

Danish experience with paediatric epilepsy surgery.

INTRODUCTION: Epilepsy surgery is increasingly used to treat children with medically intractable epilepsy. This study investigates the aetiology and seizure outcome in Danish children operated between 1996 and 2010. METHODS: Retrospectively collected data on structural magnetic resonance imaging (MRI) diagnoses, surgical procedures and seizure outcomes classified according to the Engel Classification were used. Changes over time grouped as 1996-2000, 2001-2005 and 2006-2010 were analysed. RESULTS: A total of 95 children underwent epilepsy surgery. Sixty-three operations were performed in Denmark and 50 abroad. In all, 14 children needed reoperation. The median follow-up period was four years. At the latest follow-up, Engel class I (indicating no disabling seizures) was found in 67% of the patients. Cortical dysplasia, mesial temporal sclerosis and tumour were the most common MRI findings. The percentage of tumours operated decreased over time, and frontal lobe resections increased. In the 2006-2010 period, resections with normal MRI were performed, resulting in a less favourable Engel outcome. Persistent, unexpected complications were seen in three of 113 operations. CONCLUSIONS: The majority of children who undergo epilepsy surgery have a good, worthwhile seizure outcome. The seizure outcome for Danish children corresponds to that of other epilepsy surgery centres. The clinical criteria for selection of patients changed over time. FUNDING: none. TRIAL REGISTRATION: The Danish Data Protection Agency approved the project with record number: 2013-41-2459.

Patterns of DNA damage response in intracranial germ cell tumors versus glioblastomas reflect cell of origin rather than brain environment: implications for the anti-tumor barrier concept and treatment.

The DNA damage response (DDR) machinery becomes commonly activated in response to oncogenes and during early stages of development of solid malignancies, with an exception of testicular germ cell tumors (TGCTs). The active DDR signaling evokes cell death or senescence but this anti-tumor barrier can be breached by defects in DDR factors, such as the ATM-Chk2-p53 pathway, thereby allowing tumor progression. The DDR barrier is strongly activated in brain tumors, particularly gliomas, due to oxidative damage and replication stress. Here, we took advantage of rare human primary intracranial germ cell tumors (PIGCTs), to address the roles of cell-intrinsic factors including cell of origin, versus local tissue environment, in the constitutive DDR activation in vivo. Immunohistochemical analysis of 7 biomarkers on a series of 21 PIGCTs (germinomas and other subtypes), 20 normal brain specimens and 20 glioblastomas, revealed the following: i) The overall DDR signaling (γH2AX) and activation of the ATM-Chk2-p53 pathway were very low among the PIGCTs, reminiscent of TGCTs, and contrasting sharply with strong DDR activation in glioblastomas; ii) Except for one case of embryonal carcinoma, there were no clear aberrations in the ATM-Chk2-p53 pathway components among the PIGCT cohort; iii) Subsets of PIGCTs showed unusual cytosolic localization of Chk2 and/or ATM. Collectively, these results show that PIGCTs mimic the DDR activation patterns of their gonadal germ cell tumor counterparts, rather than the brain tumors with which they share the tissue environment. Hence cell-intrinsic factors and cell of origin dictate the extent of DDR barrier activation and also the ensuing pressure to select for DDR defects. Our data provide conceptually important insights into the role of DNA damage checkpoints in intracranial tumorigenesis, with implications for the differential biological responses of diverse tumor types to endogenous stress as well as to genotoxic treatments such as ionizing radiation or chemotherapy.

Recent advances in understanding the etiology and pathogenesis of pediatric germ cell tumors.

Pediatric germ cell tumors (GCTs) are rare neoplasms arising predominantly in the gonads and sacrococcygeal, mediastinal, and intracranial localizations. In this article, we review current knowledge of pathogenesis of pediatric GCTs, which differs from adult/adolescent GCTs. One distinctive feature is the absence of a progenitor stage, such as carcinoma in situ or gonadoblastoma, which are seen in adult/adolescent GCTs, except spermatocytic seminoma. The primordial germ cell (PGC) is the suggested origin of all GCTs, with variations in histology reflecting differentiation stage. Expression of pluripotency transcription factors OCT-3/4, NANOG, and AP-2γ in germinomas/seminomas/dysgerminomas is consistent with retaining a germ cell phenotype. Teratomas, in contrast, develop through a pathway of aberrant somatic differentiation of immature germ cells, and the yolk sac tumors and choriocarcinomas result from abnormal extraembryonic differentiation. In pediatric GCTs, origin is suggested at an earlier developmental stage because of predisposing genetic factors, although responsible genes remain largely unknown. Some extragonadal GCTs have been linked to overexpression of the KIT/KITLG system, allowing for survival of aberrantly migrated ectopic PGCs. Infant gonadal/sacrococcygeal GCTs may be caused by apoptosis-related pathways, consistent with an association with polymorphisms in BAK1. Although recent advances have identified candidate pathways, further effort is needed to answer central questions of pathogenesis of these fascinating tumors.

Alternating hemiplegia of childhood in Denmark: clinical manifestations and ATP1A3 mutation status.

Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disorder characterized by early-onset recurrent distinctive hemiplegic episodes commonly accompanied by other paroxysmal features and developmental impairment. De novo mutations in ATP1A3 were recently identified as a genetic cause of AHC. To describe the entire Danish cohort of paediatric AHC patients we approached neuropaediatricians nationwide. All currently acknowledged Danish patients ≤16 years with AHC were genetically tested and seen by the same child neurologist (PU). Ten patients; seven girls and three boys were identified. Mean present age was 10.0 years (range 1-16). Mean age at presentation was 7.4 months (range 1-18 months). Sequencing of ATP1A3 in all ten patients revealed a pathogenic mutation in seven. Two females with moderate psychomotor impairment were heterozygous for the known p.G947R mutation, whereas one severely retarded boy was heterozygous for the common p.E815K mutation. The prevalent p.D801N mutation was identified in two moderate to severely retarded children. Interestingly, in a set of monochorionic male twins a novel p.D801E mutation was identified, underscoring that the asparagine at position 801 is a mutation hotspot. Three girls aged 5-13 years did not reveal any ATP1A3 mutations. They were rather mildly clinically affected and displayed a normal or near-normal psychomotor development. This is the first study of AHC in the Danish paediatric population. The patients harboured a wide range of psychomotor difficulties. Patients with no mutation detected tended to be less severely affected. Prevalence was approximately 1 per 100,000 children.

Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts: implications for pathogenesis.

This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/ß-catenin and TGF-ß/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.