A Dutch paediatric palliative care guideline: a systematic review and evidence-based recommendations for symptom treatment.

BACKGROUND: Children with life-threatening and life-limiting conditions can experience high levels of suffering due to multiple distressing symptoms that result in poor quality of life and increase risk of long-term distress in their family members. High quality symptom treatment is needed for all these children and their families, even more so at the end-of-life. In this paper, we provide evidence-based recommendations for symptom treatment in paediatric palliative patients to optimize care. METHODS: A multidisciplinary panel of 56 experts in paediatric palliative care and nine (bereaved) parents was established to develop recommendations on symptom treatment in paediatric palliative care including anxiety and depression, delirium, dyspnoea, haematological symptoms, coughing, skin complaints, nausea and vomiting, neurological symptoms, pain, death rattle, fatigue, paediatric palliative sedation and forgoing hydration and nutrition. Recommendations were based on evidence from a systematic literature search, additional literature sources (such as guidelines), clinical expertise, and patient and family values. We used the GRADE methodology for appraisal of evidence. Parents were included in the guideline panel to ensure the representation of patient and family values. RESULTS: We included a total of 18 studies that reported on the effects of specific (non) pharmacological interventions to treat symptoms in paediatric palliative care. A few of these interventions showed significant improvement in symptom relief. This evidence could only (partly) answer eight out of 27 clinical questions. We included 29 guidelines and two textbooks as additional literature to deal with lack of evidence. In total, we formulated 221 recommendations on symptom treatment in paediatric palliative care based on evidence, additional literature, clinical expertise, and patient and family values. CONCLUSION: Even though available evidence on symptom-related paediatric palliative care interventions has increased, there still is a paucity of evidence in paediatric palliative care. We urge for international multidisciplinary multi-institutional collaboration to perform high-quality research and contribute to the optimization of symptom relief in palliative care for all children worldwide.

Diagnosing, discarding, or de-VUSsing: A practical guide to (un)targeted metabolomics as variant-transcending functional tests.

PURPOSE: For patients with inherited metabolic disorders (IMDs), any diagnostic delay should be avoided because early initiation of personalized treatment could prevent irreversible health damage. To improve diagnostic interpretation of genetic data, gene function tests can be valuable assets. For IMDs, variant-transcending functional tests are readily available through (un)targeted metabolomics assays. To support the application of metabolomics for this purpose, we developed a gene-based guide to select functional tests to either confirm or exclude an IMD diagnosis. METHODS: Using information from a diagnostic IMD exome panel, Kyoto Encyclopedia of Genes and Genomes, and Inborn Errors of Metabolism Knowledgebase, we compiled a guide for metabolomics-based gene function tests. From our practical experience with this guide, we retrospectively selected illustrative cases for whom combined metabolomic/genomic testing improved diagnostic success and evaluated the effect hereof on clinical management. RESULTS: The guide contains 2047 metabolism-associated genes for which a validated or putative variant-transcending gene function test is available. We present 16 patients for whom metabolomic testing either confirmed or ruled out the presence of a second pathogenic variant, validated or ruled out pathogenicity of variants of uncertain significance, or identified a diagnosis initially missed by genetic analysis. CONCLUSION: Metabolomics-based gene function tests provide additional value in the diagnostic trajectory of patients with suspected IMD by enhancing and accelerating diagnostic success.

Interprofessional simulation of acute care for nursing and medical students: interprofessional competencies and transfer to the workplace.

BACKGROUND: Teamwork and communication are essential tools for doctors, nurses and other team members in the management of critically ill patients. Early interprofessional education during study, using acute care simulation, may improve teamwork and communication between interprofessional team members on the long run. METHODS: A comparative sequential quantitative-qualitative study was used to understand interprofessional learning outcomes in nursing and medical students after simulation of acute care. Students were assigned to a uni- or interprofessional training. Questionnaires were used to measure short and long term differences in interprofessional collaboration and communication between the intervention and control group for nursing and medical students respectively. Semi-structured focus groups were conducted to gain a better understanding of IPE in acute simulation. RESULTS: One hundred and ninety-one students participated in this study (131 medical, 60 nursing students). No differences were found between the intervention and control group in overall ICCAS scores for both medical and nursing students (p = 0.181 and p = 0.441). There were no differences in ICS scores between the intervention and control group. Focus groups revealed growing competence in interprofessional communication and collaboration for both medical and nursing students. CONCLUSIONS: Interprofessional simulation training did show measurable growth of interprofessional competencies, but so did uniprofessional training. Both medical and nursing students reported increased awareness of perspective and expertise of own and other profession. Furthermore, they reported growing competence in interprofessional communication and collaboration in transfer to their workplace.

De Novo Mutations Affecting the Catalytic Cα Subunit of PP2A, PPP2CA, Cause Syndromic Intellectual Disability Resembling Other PP2A-Related Neurodevelopmental Disorders.

Type 2A protein phosphatases (PP2As) are highly expressed in the brain and regulate neuronal signaling by catalyzing phospho-Ser/Thr dephosphorylations in diverse substrates. PP2A holoenzymes comprise catalytic C-, scaffolding A-, and regulatory B-type subunits, which determine substrate specificity and physiological function. Interestingly, de novo mutations in genes encoding A- and B-type subunits have recently been implicated in intellectual disability (ID) and developmental delay (DD). We now report 16 individuals with mild to profound ID and DD and a de novo mutation in PPP2CA, encoding the catalytic Cα subunit. Other frequently observed features were severe language delay (71%), hypotonia (69%), epilepsy (63%), and brain abnormalities such as ventriculomegaly and a small corpus callosum (67%). Behavioral problems, including autism spectrum disorders, were reported in 47% of individuals, and three individuals had a congenital heart defect. PPP2CA de novo mutations included a partial gene deletion, a frameshift, three nonsense mutations, a single amino acid duplication, a recurrent mutation, and eight non-recurrent missense mutations. Functional studies showed complete PP2A dysfunction in four individuals with seemingly milder ID, hinting at haploinsufficiency. Ten other individuals showed mutation-specific biochemical distortions, including poor expression, altered binding to the A subunit and specific B-type subunits, and impaired phosphatase activity and C-terminal methylation. Four were suspected to have a dominant-negative mechanism, which correlated with severe ID. Two missense variants affecting the same residue largely behaved as wild-type in our functional assays. Overall, we found that pathogenic PPP2CA variants impair PP2A-B56(δ) functionality, suggesting that PP2A-related neurodevelopmental disorders constitute functionally converging ID syndromes.

De Novo Missense Mutations in DHX30 Impair Global Translation and Cause a Neurodevelopmental Disorder.

DHX30 is a member of the family of DExH-box helicases, which use ATP hydrolysis to unwind RNA secondary structures. Here we identified six different de novo missense mutations in DHX30 in twelve unrelated individuals affected by global developmental delay (GDD), intellectual disability (ID), severe speech impairment and gait abnormalities. While four mutations are recurrent, two are unique with one affecting the codon of one recurrent mutation. All amino acid changes are located within highly conserved helicase motifs and were found to either impair ATPase activity or RNA recognition in different in vitro assays. Moreover, protein variants exhibit an increased propensity to trigger stress granule (SG) formation resulting in global translation inhibition. Thus, our findings highlight the prominent role of translation control in development and function of the central nervous system and also provide molecular insight into how DHX30 dysfunction might cause a neurodevelopmental disorder.

A clinical utility study of exome sequencing versus conventional genetic testing in pediatric neurology.

PURPOSE: Implementation of novel genetic diagnostic tests is generally driven by technological advances because they promise shorter turnaround times and/or higher diagnostic yields. Other aspects, including impact on clinical management or cost-effectiveness, are often not assessed in detail prior to implementation. METHODS: We studied the clinical utility of whole-exome sequencing (WES) in complex pediatric neurology in terms of diagnostic yield and costs. We analyzed 150 patients (and their parents) presenting with complex neurological disorders of suspected genetic origin. In a parallel study, all patients received both the standard diagnostic workup (e.g., cerebral imaging, muscle biopsies or lumbar punctures, and sequential gene-by-gene-based testing) and WES simultaneously. RESULTS: Our unique study design allowed direct comparison of diagnostic yield of both trajectories and provided insight into the economic implications of implementing WES in this diagnostic trajectory. We showed that WES identified significantly more conclusive diagnoses (29.3%) than the standard care pathway (7.3%) without incurring higher costs. Exploratory analysis of WES as a first-tier diagnostic test indicates that WES may even be cost-saving, depending on the extent of other tests being omitted. CONCLUSION: Our data support such a use of WES in pediatric neurology for disorders of presumed genetic origin.Genet Med advance online publication 23 March 2017.

Mutations in RARS cause hypomyelination.

Hypomyelinating disorders of the central nervous system are still a diagnostic challenge, as many patients remain without genetic diagnosis. Using magnetic resonance imaging (MRI) pattern recognition and whole exome sequencing, we could ascertain compound heterozygous mutations in RARS in 4 patients with hypomyelination. Clinical features included severe spasticity and nystagmus. RARS encodes the cytoplasmic arginyl-tRNA synthetase, an enzyme essential for RNA translation. This protein is among the subunits of the multisynthetase complex, which emerges as a key player in myelination.

Increased frequency of infections and autoimmune disease in adults with PTEN Hamartoma Tumour Syndrome.

There are indications for immune dysregulation in PTEN Hamartoma Tumour Syndrome (PHTS), however information on the clinical immune phenotype is lacking. We aimed to assess the frequency of infections and autoimmune disease in PHTS patients. A retrospective cohort study including 81 paediatric and 109 adult PHTS patients and 73 female adult controls and self-reported data from yearly surveillance visits. Differences between adult patients and controls were assessed with odds ratios (OR). Of paediatric patients, 1% reported fungal infections, 23% tonsillectomy/adenoidectomy, 36% bacterial infections requiring antibiotics, and 2% autoimmune disease. Of adult patients, up to 67% repeatedly reported fungal infections, and 73% was ever affected which was similar to controls. Compared to controls, adult patients more often reported (signs of) viral infections: tonsillectomy/adenoidectomy (78%; OR = 7.4 (95%CI: 3.7-15.8)), frequent infections during childhood (43%; OR = 2.5 (95%CI: 1.3-5.2)), and flu or cold infections more often than others (49%; OR = 3.9 (95%CI: 2.0-8.0)). Autoimmune disease was also more frequent (24%, OR = 2.7 (95%CI: 1.1-7.3)) in adult patients, and antibiotics use (38%, OR = 4.7 (95%CI: 1.3-23.0)) in female adult patients. PHTS patients experience a broad clinical phenotype of immune dysregulation. At adult age, this consists of more often viral and bacterial infections and autoimmune disease, and repetitive fungal infections.

Experience in a PHTS Expertise Centre: Yield of Thyroid Ultrasound Surveillance in Children with PTEN Hamartoma Tumor Syndrome.

Objective: Children with PTEN hamartoma tumor syndrome (PHTS) are at increased risk for developing thyroid abnormalities, including differentiated thyroid carcinoma (DTC). The Dutch PHTS guideline recommends ultrasound surveillance starting from age 18. Since the literature describes PHTS patients who developed DTC before age 18, the Dutch PHTS expertise centre has initiated annual ultrasound surveillance starting from age 12. The purpose of this study was to identify the yield of thyroid ultrasound surveillance in children. Methods: A retrospective single centre cohort study was conducted. Pediatric PHTS patients who received thyroid ultrasound surveillance before age 18 between 2016-2023 were included. Patients' medical records have been reviewed. Primary outcomes included prevalence and time to develop thyroid nodules ≥10mm, nodular growth, goiter, thyroiditis and DTC. Descriptive statistics and Kaplan-Meier analyses were performed. Results: Forty-three patients were included. Two patients (5%) were diagnosed with DTC at ages 12 and 17. Both DTCs were identified as minimally invasive follicular carcinoma at stages pT3NxMx and pT1NxMx respectively. A total of 84% were diagnosed with thyroid abnormalities at a median age of 12 years (range 9-18). Most common findings were benign, including nodular disease (74%), goiter (30%) and autoimmune thyroiditis (12%). Nodular growth was observed in 14 patients (33%) resulting in (hemi)thyroidectomy in 7 patients (16%). Conclusion: Thyroid ultrasound surveillance resulted in the detection of DTC in 2/43 PHTS patients before age 18. These findings support the recommendation to initiate thyroid ultrasound surveillance in children at least from age 12, preferably within an expertise centre.

CERT1 mutations perturb human development by disrupting sphingolipid homeostasis.

Neural differentiation, synaptic transmission, and action potential propagation depend on membrane sphingolipids, whose metabolism is tightly regulated. Mutations in the ceramide transporter CERT (CERT1), which is involved in sphingolipid biosynthesis, are associated with intellectual disability, but the pathogenic mechanism remains obscure. Here, we characterize 31 individuals with de novo missense variants in CERT1. Several variants fall into a previously uncharacterized dimeric helical domain that enables CERT homeostatic inactivation, without which sphingolipid production goes unchecked. The clinical severity reflects the degree to which CERT autoregulation is disrupted, and inhibiting CERT pharmacologically corrects morphological and motor abnormalities in a Drosophila model of the disease, which we call ceramide transporter (CerTra) syndrome. These findings uncover a central role for CERT autoregulation in the control of sphingolipid biosynthetic flux, provide unexpected insight into the structural organization of CERT, and suggest a possible therapeutic approach for patients with CerTra syndrome.

Genotype-Phenotype Comparison in POGZ-Related Neurodevelopmental Disorders by Using Clinical Scoring.

POGZ-related disorders (also known as White-Sutton syndrome) encompass a wide range of neurocognitive abnormalities and other accompanying anomalies. Disease severity varies widely among POGZ patients and studies investigating genotype-phenotype association are scarce. Therefore, our aim was to collect data on previously unreported POGZ patients and perform a large-scale phenotype-genotype comparison from published data. Overall, 117 POGZ patients' genotype and phenotype data were included in the analysis, including 12 novel patients. A severity scoring system was developed for the comparison. Mild and severe phenotypes were compared with the types and location of the variants and the predicted presence or absence of nonsense-mediated RNA decay (NMD). Missense variants were more often associated with mild phenotypes (p = 0.0421) and truncating variants predicted to escape NMD presented with more severe phenotypes (p < 0.0001). Within this group, variants in the prolin-rich region of the POGZ protein were associated with the most severe phenotypes (p = 0.0004). Our study suggests that gain-of-function or dominant negative effect through escaping NMD and the location of the variants in the prolin-rich domain of the protein may play an important role in the severity of manifestations of POGZ-associated neurodevelopmental disorders.

Reanalysis of exome negative patients with rare disease: a pragmatic workflow for diagnostic applications.

BACKGROUND: Approximately two third of patients with a rare genetic disease remain undiagnosed after exome sequencing (ES). As part of our post-test counseling procedures, patients without a conclusive diagnosis are advised to recontact their referring clinician to discuss new diagnostic opportunities in due time. We performed a systematic study of genetically undiagnosed patients 5 years after their initial negative ES report to determine the efficiency of diverse reanalysis strategies. METHODS: We revisited a cohort of 150 pediatric neurology patients originally enrolled at Radboud University Medical Center, of whom 103 initially remained genetically undiagnosed. We monitored uptake of physician-initiated routine clinical and/or genetic re-evaluation (ad hoc re-evaluation) and performed systematic reanalysis, including ES-based resequencing, of all genetically undiagnosed patients (systematic re-evaluation). RESULTS: Ad hoc re-evaluation was initiated for 45 of 103 patients and yielded 18 diagnoses (including 1 non-genetic). Subsequent systematic re-evaluation identified another 14 diagnoses, increasing the diagnostic yield in our cohort from 31% (47/150) to 53% (79/150). New genetic diagnoses were established by reclassification of previously identified variants (10%, 3/31), reanalysis with enhanced bioinformatic pipelines (19%, 6/31), improved coverage after resequencing (29%, 9/31), and new disease-gene associations (42%, 13/31). Crucially, our systematic study also showed that 11 of the 14 further conclusive genetic diagnoses were made in patients without a genetic diagnosis that did not recontact their referring clinician. CONCLUSIONS: We find that upon re-evaluation of undiagnosed patients, both reanalysis of existing ES data as well as resequencing strategies are needed to identify additional genetic diagnoses. Importantly, not all patients are routinely re-evaluated in clinical care, prolonging their diagnostic trajectory, unless systematic reanalysis is facilitated. We have translated our observations into considerations for systematic and ad hoc reanalysis in routine genetic care.

Red flags for early recognition of adult patients with PTEN Hamartoma Tumour Syndrome.

Patients with PTEN Hamartoma Tumour Syndrome (PHTS) are at increased risk of developing cancer. Many adult PHTS patients are not recognized as such and do not receive the cancer surveillance they need. Our aim was to define phenotypic characteristics that can easily be assessed and manifest by early adulthood, and hence could serve as red flags (i.e. alerting signals) for early recognition of adult patients at high risk of PHTS. Phenotypic characteristics including macrocephaly, multinodular goitre (MNG), and oral features were examined in 81 paediatric and 86 adult PHTS patients by one of two medical experts during yearly surveillance visits at our Dutch PHTS expert centre between 1997 and 2020. MNG was defined as signs of thyroid nodules and/or goitre. Oral features included gingival hypertrophy, high palate (adults only) and oral papillomas. Based on the characteristics' prevalence in different age groups, combinations of phenotypic characteristics were defined and evaluated on their potential to recognize individuals with PHTS. Macrocephaly was present in 100% of paediatric and 67% of adult patients. The prevalence of MNG was ∼50% in paediatric and gradually increased to >90% in adult patients. Similar percentages were observed for any of the oral features. Scoring two out of three of these characteristics yielded a sensitivity of 100% (95%CI 94-100%) in adults. The presence of the combination macrocephaly, MNG, or multiple oral features could serve as a red flag for general practitioners, medical specialists, and dentists to consider further assessment of the diagnosis PHTS in adults. In this way, recognition of adult PHTS patients might be improved and cancer surveillance can be offered timely.

KIF1A variants are a frequent cause of autosomal dominant hereditary spastic paraplegia.

Variants in the KIF1A gene can cause autosomal recessive spastic paraplegia 30, autosomal recessive hereditary sensory neuropathy, or autosomal (de novo) dominant mental retardation type 9. More recently, variants in KIF1A have also been described in a few cases with autosomal dominant spastic paraplegia. Here, we describe 20 KIF1A variants in 24 patients from a clinical exome sequencing cohort of 347 individuals with a mostly 'pure' spastic paraplegia. In these patients, spastic paraplegia was slowly progressive and mostly pure, but with a highly variable disease onset (0-57 years). Segregation analyses showed a de novo occurrence in seven cases, and a dominant inheritance pattern in 11 families. The motor domain of KIF1A is a hotspot for disease causing variants in autosomal dominant spastic paraplegia, similar to mental retardation type 9 and recessive spastic paraplegia type 30. However, unlike these allelic disorders, dominant spastic paraplegia was also caused by loss-of-function variants outside this domain in six families. Finally, three missense variants were outside the motor domain and need further characterization. In conclusion, KIF1A variants are a frequent cause of autosomal dominant spastic paraplegia in our cohort (6-7%). The identification of KIF1A loss-of-function variants suggests haploinsufficiency as a possible mechanism in autosomal dominant spastic paraplegia.

The Genetic Homogeneity of CAPOS Syndrome: Four New Patients With the c.2452G>A (p.Glu818Lys) Mutation in the ATP1A3 Gene.

BACKGROUND: The clinical syndrome of cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS) was first described 20 years ago, but it was only recently that whole exome sequencing unveiled the causative mutation in the ATP1A3 gene. We present four patients from the seventh and eighth family identified worldwide, provide a critical review of all patients published thus far, and speculate about the pathophysiologic processes underlying the acute neurological manifestations. CLINICAL OBSERVATIONS: The individuals presented here experienced one to three paroxysmal, short-lasting episodes in childhood with cerebellar symptoms and signs, hypotonia, ophthalmoparesis, motor weakness, areflexia, and/or lethargy that were consistently associated with febrile illness. An underlying c.2452G>A mutation in the ATP1A3 gene was found in all four individuals. Besides the persisting CAPOS features, other possibly related sequelae included dystonia, myoclonus, and emotional and behavioral changes. After initiation of acetazolamide in two patients, no further episodes occurred. CONCLUSION: Targeted sequencing of the ATP1A3 gene is recommended in children exhibiting paroxysmal, fever-induced ataxia and in adults with a more or less stationary or slowly progressive cerebellar syndrome since childhood accompanied by mixed combinations of areflexia, pes cavus, profound visual impairment, and/or sensorineural hearing loss. Similar to some other types of episodic ataxia, acetazolamide may be considered in patients with CAPOS syndrome to prevent or attenuate bouts of ataxia, but this requires further study.

Acute toxicity profile of craniospinal irradiation with intensity-modulated radiation therapy in children with medulloblastoma: A prospective analysis.

BACKGROUND: To report on the acute toxicity in children with medulloblastoma undergoing intensity-modulated radiation therapy (IMRT) with daily intrafractionally modulated junctions. METHODS: Newly diagnosed patients, aged 3-21, with standard-risk (SR) or high-risk (HR) medulloblastoma were eligible. A dose of 23.4 or 36.0 Gy in daily fractions of 1.8 Gy was prescribed to the craniospinal axis, followed by a boost to the primary tumor bed (54 or 55.8 Gy) and metastases (39.6-55.8 Gy), when indicated. Weekly, an intravenous bolus of vincristine was combined for patients with SR medulloblastoma and patients participating in the COG-ACNS-0332 study. Common toxicity criteria (CTC, version 2.0) focusing on skin, alopecia, voice changes, conjunctivitis, anorexia, dysphagia, gastro-intestinal symptoms, headache, fatigue and hematological changes were scored weekly during radiotherapy. RESULTS: From 2010 to 2014, data from 15 consecutive patients (SR, n = 7; HR, n = 8) were collected. Within 72 h from onset of treatment, vomiting (66 %) and headache (46 %) occurred. During week 3 of treatment, a peak incidence in constipation (33 %) and abdominal pain/cramping (40 %) was observed, but only in the subgroup of patients (n = 9) receiving vincristine (constipation: 56 vs 0 %, P = .04; pain/cramping: 67 vs 0 %, P = .03). At week 6, 73 % of the patients developed faint erythema of the cranial skin with dry desquamation (40 %) or moist desquamation confined to the skin folds of the auricle (33 %). No reaction of the skin overlying the spinal target volume was observed. CONCLUSIONS: Headache at onset and gastro-intestinal toxicity, especially in patients receiving weekly vincristine, were the major complaints of patients with medulloblastoma undergoing craniospinal irradiation with IMRT.

Altered PLP1 splicing causes hypomyelination of early myelinating structures.

OBJECTIVE: The objective of this study was to investigate the genetic etiology of the X-linked disorder "Hypomyelination of Early Myelinating Structures" (HEMS). METHODS: We included 16 patients from 10 families diagnosed with HEMS by brain MRI criteria. Exome sequencing was used to search for causal mutations. In silico analysis of effects of the mutations on splicing and RNA folding was performed. In vitro gene splicing was examined in RNA from patients' fibroblasts and an immortalized immature oligodendrocyte cell line after transfection with mutant minigene splicing constructs. RESULTS: All patients had unusual hemizygous mutations of PLP1 located in exon 3B (one deletion, one missense and two silent), which is spliced out in isoform DM20, or in intron 3 (five mutations). The deletion led to truncation of PLP1, but not DM20. Four mutations were predicted to affect PLP1/DM20 alternative splicing by creating exonic splicing silencer motifs or new splice donor sites or by affecting the local RNA structure of the PLP1 splice donor site. Four deep intronic mutations were predicted to destabilize a long-distance interaction structure in the secondary PLP1 RNA fragment involved in regulating PLP1/DM20 alternative splicing. Splicing studies in fibroblasts and transfected cells confirmed a decreased PLP1/DM20 ratio. INTERPRETATION: Brain structures that normally myelinate early are poorly myelinated in HEMS, while they are the best myelinated structures in Pelizaeus-Merzbacher disease, also caused by PLP1 alterations. Our data extend the phenotypic spectrum of PLP1-related disorders indicating that normal PLP1/DM20 alternative splicing is essential for early myelination and support the need to include intron 3 in diagnostic sequencing.