Management of seizures in patients with primary mitochondrial diseases: consensus statement from the InterERNs Mitochondrial Working Group

BACKGROUND AND PURPOSE

Primary mitochondrial diseases (PMDs) are common inborn errors of energy metabolism, with an estimated prevalence of one in 4300. These disorders typically affect tissues with high energy requirements, including heart, muscle and brain. Epilepsy may be the presenting feature of PMD, can be difficult to treat and often represents a poor prognostic feature. The aim of this study was to develop guidelines and consensus recommendations on safe medication use and seizure management in mitochondrial epilepsy.

METHODS

A panel of 24 experts in mitochondrial medicine, pharmacology and epilepsy management of adults and/or children and two patient representatives from seven countries was established. Experts were members of five different European Reference Networks, known as the Mito InterERN Working Group. A Delphi technique was used to allow the panellists to consider draft recommendations on safe medication use and seizure management in mitochondrial epilepsy, using two rounds with predetermined levels of agreement.

RESULTS

A high level of consensus was reached regarding the safety of 14 out of all 25 drugs reviewed, resulting in endorsement of National Institute for Health and Care Excellence guidelines for seizure management, with some modifications. Exceptions including valproic acid in POLG disease, vigabatrin in patients with γ-aminobutyric acid transaminase deficiency and topiramate in patients at risk for renal tubular acidosis were highlighted.

CONCLUSIONS

These consensus recommendations describe our intent to improve seizure control and reduce the risk of drug-related adverse events in individuals living with PMD-related epilepsy.

The approach to extracorporeal cardiopulmonary resuscitation (ECPR) in children. A narrative review by the paediatric ECPR working group of EuroELSO

Extracorporeal Cardiopulmonary Resuscitation (ECPR) has potential benefits compared to conventional Cardiopulmonary Resuscitation (CCPR) in children. Although no randomised trials for paediatric ECPR have been conducted, there is extensive literature on survival, neurological outcome and risk factors for survival. Based on current literature and guidelines, we suggest recommendations for deployment of paediatric ECPR emphasising the requirement for protocols, training, and timely intervention to enhance patient outcomes. Factors related to outcomes of paediatric ECPR include initial underlying rhythm, CCPR duration, quality of CCPR, medications during CCPR, cannulation site, acidosis and renal dysfunction. Based on current evidence and experience, we provide an approach to patient selection, ECMO initiation and management in ECPR regarding blood and sweep flow settings, unloading of the left ventricle, diagnostics whilst on ECMO, temperature targets, neuromonitoring as well as suggested weaning and decannulation strategies.

Developmental outcome of electroencephalographic findings in SYNGAP1 encephalopathy

SYNGAP1 haploinsufficiency results in a developmental and epileptic encephalopathy (DEE) causing generalized epilepsies accompanied by a spectrum of neurodevelopmental symptoms. Concerning interictal epileptiform discharges (IEDs) in electroencephalograms (EEG), potential biomarkers have been postulated, including changes in background activity, fixation-off sensitivity (FOS) or eye closure sensitivity (ECS). In this study we clinically evaluate a new cohort of 36 SYNGAP1-DEE individuals. Standardized questionnaires were employed to collect clinical, electroencephalographic and genetic data. We investigated electroencephalographic findings, focusing on the cortical distribution of interictal abnormalities and their changes with age. Among the 36 SYNGAP1-DEE cases 18 presented variants in the SYNGAP1 gene that had never been previously reported. The mean age of diagnosis was 8 years and 8 months, ranging from 2 to 17 years, with 55.9% being male. All subjects had global neurodevelopmental/language delay and behavioral abnormalities; 83.3% had moderate to profound intellectual disability (ID), 91.7% displayed autistic traits, 73% experienced sleep disorders and 86.1% suffered from epileptic seizures, mainly eyelid myoclonia with absences (55.3%). A total of 63 VEEGs were revised, observing a worsening of certain EEG findings with increasing age. A disorganized background was observed in all age ranges, yet this was more common among older cases. The main IEDs were bilateral synchronous and asynchronous posterior discharges, accounting for ≥50% in all age ranges. Generalized alterations with maximum amplitude in the anterior region showed as the second most frequent IED (≥15% in all age ranges) and were also more common with increasing age. Finally, diffuse fast activity was much more prevalent in cases with 6 years or older. To the best of our knowledge, this is the first study to analyze EEG features across different age groups, revealing an increase in interictal abnormalities over infancy and adolescence. Our findings suggest that SYNGAP1 haploinsufficiency has complex effects in human brain development, some of which might unravel at different developmental stages. Furthermore, they highlight the potential of baseline EEG to identify candidate biomarkers and the importance of natural history studies to develop specialized therapies and clinical trials.

Metabolic characterization of neurogenetic disorders involving glutamatergic neurotransmission

The study of inborn errors of neurotransmission has been mostly focused on monoamine disorders, GABAergic and glycinergic defects. The study of the glutamatergic synapse using the same approach than classic neurotransmitter disorders is challenging due to the lack of biomarkers in the CSF. A metabolomic approach can provide both insight into their molecular basis and outline novel therapeutic alternatives. We have performed a semi-targeted metabolomic analysis on CSF samples from 25 patients with neurogenetic disorders with an important expression in the glutamatergic synapse and 5 controls. Samples from patients diagnosed with MCP2, CDKL5-, GRINpathies and STXBP1-related encephalopathies were included. We have performed univariate (UVA) and multivariate statistical analysis (MVA), using Wilcoxon rank-sum test, principal component analysis (PCA), and OPLS-DA. By using the results of both analyses, we have identified the metabolites that were significantly altered and that were important in clustering the respective groups. On these, we performed pathway- and network-based analyses to define which metabolic pathways were possibly altered in each pathology. We have observed alterations in the tryptophan and branched-chain amino acid metabolism pathways, which interestingly converge on LAT1 transporter-dependency to cross the blood-brain barrier (BBB). Analysis of the expression of LAT1 transporter in brain samples from a mouse model of Rett syndrome (MECP2) revealed a decrease in the transporter expression, that was already noticeable at pre-symptomatic stages. The study of the glutamatergic synapse from this perspective advances the understanding of their pathophysiology, shining light on an understudied feature as is their metabolic signature.

Leigh syndrome is the main clinical characteristic of PTCD3 deficiency

Mitochondrial translation defects are a continuously growing group of disorders showing a large variety of clinical symptoms including a wide range of neurological abnormalities. To date, mutations in PTCD3, encoding a component of the mitochondrial ribosome, have only been reported in a single individual with clinical evidence of Leigh syndrome. Here, we describe three additional PTCD3 individuals from two unrelated families, broadening the genetic and phenotypic spectrum of this disorder, and provide definitive evidence that PTCD3 deficiency is associated with Leigh syndrome. The patients presented in the first months of life with psychomotor delay, respiratory insufficiency and feeding difficulties. The neurologic phenotype included dystonia, optic atrophy, nystagmus and tonic-clonic seizures. Brain MRI showed optic nerve atrophy and thalamic changes, consistent with Leigh syndrome. WES and RNA-seq identified compound heterozygous variants in PTCD3 in both families: c.[1453-1G>C];[1918C>G] and c.[710del];[902C>T]. The functional consequences of the identified variants were determined by a comprehensive characterization of the mitochondrial function. PTCD3 protein levels were significantly reduced in patient fibroblasts and, consistent with a mitochondrial translation defect, a severe reduction in the steady state levels of complexes I and IV subunits was detected. Accordingly, the activity of these complexes was also low, and high-resolution respirometry showed a significant decrease in the mitochondrial respiratory capacity. Functional complementation studies demonstrated the pathogenic effect of the identified variants since the expression of wild-type PTCD3 in immortalized fibroblasts restored the steady-state levels of complexes I and IV subunits as well as the mitochondrial respiratory capacity. Additionally, minigene assays demonstrated that three of the identified variants were pathogenic by altering PTCD3 mRNA processing. The fourth variant was a frameshift leading to a truncated protein. In summary, we provide evidence of PTCD3 involvement in human disease confirming that PTCD3 deficiency is definitively associated with Leigh syndrome.

Liver-Directed Adeno-Associated Virus-Mediated Gene Therapy for Mucopolysaccharidosis Type VI

Gene Therapy for Mucopolysaccharidosis Type VIIn this open-label gene therapy study, infusions for MPS type VI occurred without severe adverse events. In the high-dose cohort, serum active arylsulfatase B reached 30% to 100% of normal. A modest urinary GAG increase did not require reintroduction of enzyme replacement therapy. Clinical deterioration was not noted for up to 2 years after therapy.

Exercise Compared to Mindfulness for Physical and Mental Wellbeing in Medical Students

Aim Physical Activity (PA) and Mindfulness-Based Stress Reduction (MBSR) both have positive effects on medical student well-being. The 'MED-WELL' programme is a curricular intervention that combines PA and education on exercise as medicine. This trial evaluates whether there is a mean difference in outcomes of participants of an exercise intervention, the 'MED-WELL' programme, versus a control group which engages in a MBSR programme. Methods All second-year medical students were voluntarily allocated into the intervention or control group. Data on overall health and well-being, sleep quality, loneliness, current level of PA, and confidence in prescribing exercise as medicine was analysed from both groups at baseline and after eight weeks. Results Within groups the intervention and control groups showed statistically significant improvements in overall well-being (p=0.010, p=0.005 respectively) and in sleep quality (p<0.001, p=0.007 respectively). The intervention group had statistically significant improvements in levels of PA (p=0.003) and confidence in prescribing exercise (p<0.001). However, there were no statistically significant differences in changes in outcome measures between groups. Conclusion This study has shown that participants in an exercise intervention, the 'MED-WELL' programme, had similar improvements in overall wellbeing and sleep quality to those in a control group who participated in a MBSR programme of the same duration.

Diagnosis of Genetic White Matter Disorders by Singleton Whole-Exome and Genome Sequencing Using Interactome-Driven Prioritization

Background and Objectives

Genetic white matter disorders (GWMD) are of heterogeneous origin, with >100 causal genes identified to date. Classic targeted approaches achieve a molecular diagnosis in only half of all patients. We aimed to determine the clinical utility of singleton whole-exome sequencing and whole-genome sequencing (sWES-WGS) interpreted with a phenotype- and interactome-driven prioritization algorithm to diagnose GWMD while identifying novel phenotypes and candidate genes.

Methods

A case series of patients of all ages with undiagnosed GWMD despite extensive standard-of-care paraclinical studies were recruited between April 2017 and December 2019 in a collaborative study at the Bellvitge Biomedical Research Institute (IDIBELL) and neurology units of tertiary Spanish hospitals. We ran sWES and WGS and applied our interactome-prioritization algorithm based on the network expansion of a seed group of GWMD-related genes derived from the Human Phenotype Ontology terms of each patient.

Results

We evaluated 126 patients (101 children and 25 adults) with ages ranging from 1 month to 74 years. We obtained a first molecular diagnosis by singleton WES in 59% of cases, which increased to 68% after annual reanalysis, and reached 72% after WGS was performed in 16 of the remaining negative cases. We identified variants in 57 different genes among 91 diagnosed cases, with the most frequent being RNASEH2B, EIF2B5, POLR3A, and PLP1, and a dual diagnosis underlying complex phenotypes in 6 families, underscoring the importance of genomic analysis to solve these cases. We discovered 9 candidate genes causing novel diseases and propose additional putative novel candidate genes for yet-to-be discovered GWMD.

Discussion

Our strategy enables a high diagnostic yield and is a good alternative to trio WES/WGS for GWMD. It shortens the time to diagnosis compared to the classical targeted approach, thus optimizing appropriate management. Furthermore, the interactome-driven prioritization pipeline enables the discovery of novel disease-causing genes and phenotypes, and predicts novel putative candidate genes, shedding light on etiopathogenic mechanisms that are pivotal for myelin generation and maintenance.

Pediatric Gaucher disease with intermediate type 2-3 phenotype associated with parkinsonian features and levodopa responsiveness

INTRODUCTION

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by a deficiency of acid β-glucosidase encoded by the GBA gene. In patients with GD, childhood onset parkinsonian features have been rarely described.

METHODS

Twin siblings with GD are described, including clinical follow-up and treatment response. Bone marrow, enzyme activity studies and genotyping were performed.

RESULTS

By age 9 months, symptoms at onset were thrombocytopenia and splenomegaly. By age 2, hypokinesia, bradykinesia and oculomotor apraxia were observed. By age 5 a complete rigid hypokinetic syndrome was stablished in both patients, including bradykinesia, tremor and rigidity. Treatment with imiglucerase, miglustat, ambroxol and levodopa were performed. Levodopa showed a good response with improvement in motor and non-motor skills. Foamy cells were found in the bone marrow study. Glucocerebrosidase activity was 28% and 26%. Sanger sequencing analysis identified a missense mutation and a complex allele (NP_000148: p.[(Asp448His)]; [(Leu422Profs*4)]) in compound heterozygosity in GBA gene.

CONCLUSIONS

Two siblings with neuronopathic GD with an intermediate form between type 2 and 3, with a systemic and neurological phenotype are described. The complex neurological picture included a hypokinetic-rigid and tremor syndrome that improved with levodopa treatment. These conditions together have not been previously described in pediatric GD. We suggest that in children with parkinsonian features, lysosomal storage disorders must be considered, and a levodopa trial must be performed. Moreover, this report give support to the finding that GBA and parkinsonian features share biological pathways and highlight the importance of lysosomal mechanisms in parkinsonism pathogenesis, what might have therapeutic implications.

Safety of drug use in patients with a primary mitochondrial disease: An international Delphi-based consensus

Clinical guidance is often sought when prescribing drugs for patients with primary mitochondrial disease. Theoretical considerations concerning drug safety in patients with mitochondrial disease may lead to unnecessary withholding of a drug in a situation of clinical need. The aim of this study was to develop consensus on safe medication use in patients with a primary mitochondrial disease. A panel of 16 experts in mitochondrial medicine, pharmacology, and basic science from six different countries was established. A modified Delphi technique was used to allow the panellists to consider draft recommendations anonymously in two Delphi rounds with predetermined levels of agreement. This process was supported by a review of the available literature and a consensus conference that included the panellists and representatives of patient advocacy groups. A high level of consensus was reached regarding the safety of all 46 reviewed drugs, with the knowledge that the risk of adverse events is influenced both by individual patient risk factors and choice of drug or drug class. This paper details the consensus guidelines of an expert panel and provides an important update of previously established guidelines in safe medication use in patients with primary mitochondrial disease. Specific drugs, drug groups, and clinical or genetic conditions are described separately as they require special attention. It is important to emphasise that consensus-based information is useful to provide guidance, but that decisions related to drug prescribing should always be tailored to the specific needs and risks of each individual patient. We aim to present what is current knowledge and plan to update this regularly both to include new drugs and to review those currently included.

Molecular characterization of Spanish patients with MECP2 duplication syndrome

MECP2 duplication syndrome (MDS) is an X-linked neurodevelopmental disorder characterized by a severe to profound intellectual disability, early onset hypotonia and diverse psycho-motor and behavioural features. To date, fewer than 200 cases have been published. We report the clinical and molecular characterization of a Spanish MDS cohort that included 19 boys and 2 girls. Clinical suspicions were confirmed by array comparative genomic hybridization and multiplex ligation-dependent probe amplification (MLPA). Using, a custom in-house MLPA assay, we performed a thorough study of the minimal duplicated region, from which we concluded a complete duplication of both MECP2 and IRAK1 was necessary for a correct MDS diagnosis, as patients with partial MECP2 duplications lacked some typical clinical traits present in other MDS patients. In addition, the duplication location may be related to phenotypic severity. This observation may provide a new approach for genotype-phenotype correlations, and thus more personalized genetic counselling.

Five new cases of syndromic intellectual disability due to KAT6A mutations: widening the molecular and clinical spectrum

BACKGROUND

Pathogenic variants of the lysine acetyltransferase 6A or KAT6A gene are associated with a newly identified neurodevelopmental disorder characterized mainly by intellectual disability of variable severity and speech delay, hypotonia, and heart and eye malformations. Although loss of function (LoF) mutations were initially reported as causing this disorder, missense mutations, to date always involving serine residues, have recently been associated with a form of the disorder without cardiac involvement.

RESULTS

In this study we present five new patients, four with truncating mutations and one with a missense change and the only one not presenting with cardiac anomalies. The missense change [p.(Gly359Ser)], also predicted to affect splicing by in silico tools, was functionally tested in the patient's lymphocyte RNA revealing a splicing effect for this allele that would lead to a frameshift and premature truncation.

CONCLUSIONS

An extensive revision of the clinical features of these five patients revealed high concordance with the 80 cases previously reported, including developmental delay with speech delay, feeding difficulties, hypotonia, a high bulbous nose, and recurrent infections. Other features present in some of these five patients, such as cryptorchidism in males, syndactyly, and trigonocephaly, expand the clinical spectrum of this syndrome.

New insights into genetic variant spectrum and genotype-phenotype correlations of Rubinstein-Taybi syndrome in 39 CREBBP-positive patients

Background

Rubinstein‐Taybi syndrome (RSTS) is a rare congenital disorder characterized by broad thumbs and halluces, intellectual disability, distinctive facial features, and growth retardation. Clinical manifestations of RSTS are varied and overlap with other syndromes’ phenotype, which makes clinical diagnosis challenging. CREBBP is the major causative gene (55%–60% of the cases), whereas pathogenic variants found in EP300 represent the molecular cause in 8% of RSTS patients. A wide range of CREBBP pathogenic variants have been reported so far, including point mutations (30%–50%) and large deletions (10%).

Methods

The aim of this study was to characterize the CREBBP genetic variant spectrum in 39 RSTS patients using Multiplex Ligation‐dependent Probe Amplification and DNA sequencing techniques (Sanger and Trio‐based whole‐exome sequencing).

Results

We identified 15 intragenic deletions/duplications, ranging from one exon to the entire gene. As a whole, 25 de novo point variants were detected: 4 missense, 12 nonsense, 5 frameshift, and 4 splicing pathogenic variants. Three of them were classified as of uncertain significance and one of the patients carried two different variants.

Conclusion

Seventeen of the 40 genetic variants detected were reported for the first time in this work contributing, thus, to expand the molecular knowledge of this complex disorder.

X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern.

Genetic Landscape of Rett Syndrome Spectrum: Improvements and Challenges

Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that primarily affects females, resulting in severe cognitive and physical disabilities, and is one of the most prevalent causes of intellectual disability in females. More than fifty years after the first publication on Rett syndrome, and almost two decades since the first report linking RTT to the MECP2 gene, the research community's effort is focused on obtaining a better understanding of the genetics and the complex biology of RTT and Rett-like phenotypes without MECP2 mutations. Herein, we review the current molecular genetic studies, which investigate the genetic causes of RTT or Rett-like phenotypes which overlap with other genetic disorders and document the swift evolution of the techniques and methodologies employed. This review also underlines the clinical and genetic heterogeneity of the Rett syndrome spectrum and provides an overview of the RTT-related genes described to date, many of which are involved in epigenetic gene regulation, neurotransmitter action or RNA transcription/translation. Finally, it discusses the importance of including both phenotypic and genetic diagnosis to provide proper genetic counselling from a patient's perspective and the appropriate treatment.

Cerebrospinal fluid monoamines, pterins, and folate in patients with mitochondrial diseases: systematic review and hospital experience

Mitochondrial diseases are a group of genetic disorders leading to the dysfunction of mitochondrial energy metabolism pathways. We aimed to assess the clinical phenotype and the biochemical cerebrospinal fluid (CSF) biogenic amine profiles of patients with different diagnoses of genetic mitochondrial diseases. We recruited 29 patients with genetically confirmed mitochondrial diseases harboring mutations in either nuclear or mitochondrial DNA (mtDNA) genes. Signs and symptoms of impaired neurotransmission and neuroradiological data were recorded. CSF monoamines, pterins, and 5-methyltetrahydrofolate (5MTHF) concentrations were analyzed using high-performance liquid chromatography with electrochemical and fluorescence detection procedures. The mtDNA mutations were studied by Sanger sequencing, Southern blot, and real-time PCR, and nuclear DNA was assessed either by Sanger or next-generation sequencing. Five out of 29 cases showed predominant dopaminergic signs not attributable to basal ganglia involvement, harboring mutations in different nuclear genes. A chi-square test showed a statistically significant association between high homovanillic acid (HVA) values and low CSF 5-MTHF values (chi-square = 10.916; p = 0.001). Seven out of the eight patients with high CSF HVA values showed cerebral folate deficiency. Five of them harbored mtDNA deletions associated with Kearns-Sayre syndrome (KSS), one had a mitochondrial point mutation at the mtDNA ATPase6 gene, and one had a POLG mutation. In conclusion, dopamine deficiency clinical signs were present in some patients with mitochondrial diseases with different genetic backgrounds. High CSF HVA values, together with a severe cerebral folate deficiency, were observed in KSS patients and in other mtDNA mutation syndromes.

PLA2G6-associated neurodegeneration: New insights into brain abnormalities and disease progression

INTRODUCTION

PLA2G6-associated neurodegeneration (PLAN) comprises a continuum of three phenotypes with overlapping clinical and radiologic features.

METHODS

Observational clinical study in a cohort of infantile and childhood onset PLAN patients and genetic analysis of the PLA2G6 gene. We analysed chronological evolution in terms of age at onset and disease course through a 66-item questionnaire. We performed qualitative and quantitative assessment of MRI abnormalities and searched for clinical and radiological phenotype and genotype correlations.

RESULTS

Sixteen PLAN patients (mean age: 10.2 years, range 3-33) were evaluated, with a median onset (years) of signs/symptoms as follows: neurological regression (1.5), oculomotor abnormalities (1.5), hypotonia (1.8), gait loss (2.2), pyramidal signs (3.0), axonal neuropathy (3.0), dysphagia (4.0), optic atrophy (4.0), psychiatric symptoms (4.0), seizures (5.9), joint contractures (6.0), dystonia (8.0), bladder dysfunction (13.0) and parkinsonism (15.0). MRI assessment identified cerebellar atrophy (19/19), brain iron deposition (10/19), clava hypertrophy (8/19) and T2/FLAIR hyperintensity of the cerebellar cortex (6/19). The mid-sagittal vermis relative diameter (MVRD) correlated with age at onset of clinical variants, meaning that the earlier the onset, the more severe the cerebellar atrophy. All patients harboured missense, nonsense and frameshift mutations in PLA2G6, including four novel variants.

CONCLUSIONS

Cerebellar atrophy was a universal radiological sign in infantile and childhood onset PLAN, and correlated with the severity of the phenotype. Iron accumulation within the globus pallidum and substantia nigra was also a common and strikingly uniform feature regardless of the phenotype.

Elosulfase alfa for mucopolysaccharidosis type IVA: Real-world experience in 7 patients from the Spanish Morquio-A early access program

There is a growing interest in evaluating the effectiveness of enzyme replacement therapy (ERT) with elosulfase alfa in patients with mucopolysaccharidosis type IVA (MPS-IVA) under real-world conditions. We present the experience of seven pediatric MPS-IVA patients from the Spanish Morquio-A Early Access Program. Efficacy was evaluated based on the distance walked in the 6-min walking test (6-MWT) and the 3-min-stair-climb-test (3-MSCT) at baseline and after 8 months of ERT treatment. Additionally, urinary glycosaminoglycans were measured, and a molecular analysis of a GALNS mutation was performed. The health-related quality of life was evaluated using the EuroQoL (EQ)-5D-5 L. The distance walked according to the 6-MWT ranged from 0 to 325 m at baseline and increased to 12-300 m after 8 months with elosulfase alfa (the walked distance improved in all patients except one). An increase was observed for the two patients who had to use a wheelchair. Improvements were also observed for the 3-MSCT in four patients, whereas two patients showed no changes. Three patients showed an improvement in the EQ-VAS score, whereas the scores of three patients remained stable. Regarding urinary glycosaminoglycans measurements, an irregular response was observed. Our results showed overall improvement in endurance and functionality after 8 months of elosulfase alfa treatment in a heterogeneous subset of MPS IVA patients with severe clinical manifestations managed in a real-world setting.

Neuromuscular Manifestations in Mitochondrial Diseases in Children

Mitochondrial diseases exhibit significant clinical and genetic heterogeneity. Mitochondria are highly dynamic organelles that are the major contributor of adenosine triphosphate, through oxidative phosphorylation. These disorders may be developed at any age, with isolated or multiple system involvement, and in any pattern of inheritance. Defects in the mitochondrial respiratory chain impair energy production and almost invariably involve skeletal muscle and peripheral nerves, causing exercise intolerance, cramps, recurrent myoglobinuria, or fixed weakness, which often affects extraocular muscles and results in droopy eyelids (ptosis), progressive external ophthalmoplegia, peripheral ataxia, and peripheral polyneuropathy. This review describes the main neuromuscular symptomatology through different syndromes reported in the literature and from our experience. We want to highlight the importance of searching for the "clue clinical signs" associated with inheritance pattern as key elements to guide the complex diagnosis process and genetic studies in mitochondrial diseases.

GDF-15 Is Elevated in Children with Mitochondrial Diseases and Is Induced by Mitochondrial Dysfunction

Background

We previously described increased levels of growth and differentiation factor 15 (GDF-15) in skeletal muscle and serum of patients with mitochondrial diseases. Here we evaluated GDF-15 as a biomarker for mitochondrial diseases affecting children and compared it to fibroblast-growth factor 21 (FGF-21). To investigate the mechanism of GDF-15 induction in these pathologies we measured its expression and secretion in response to mitochondrial dysfunction.

Methods

We analysed 59 serum samples from 48 children with mitochondrial disease, 19 samples from children with other neuromuscular diseases and 33 samples from aged-matched healthy children. GDF-15 and FGF-21 circulating levels were determined by ELISA.

Results

Our results showed that in children with mitochondrial diseases GDF-15 levels were on average increased by 11-fold (mean 4046pg/ml, 1492 SEM) relative to healthy (350, 21) and myopathic (350, 32) controls. The area under the curve for the receiver-operating-characteristic curve for GDF-15 was 0.82 indicating that it has a good discriminatory power. The overall sensitivity and specificity of GDF-15 for a cut-off value of 550pg/mL was 67.8% (54.4%-79.4%) and 92.3% (81.5%-97.9%), respectively. We found that elevated levels of GDF-15 and or FGF-21 correctly identified a larger proportion of patients than elevated levels of GDF-15 or FGF-21 alone. GDF-15, as well as FGF-21, mRNA expression and protein secretion, were significantly induced after treatment of myotubes with oligomycin and that levels of expression of both factors significantly correlated.

Conclusions

Our data indicate that GDF-15 is a valuable serum quantitative biomarker for the diagnosis of mitochondrial diseases in children and that measurement of both GDF-15 and FGF-21 improves the disease detection ability of either factor separately. Finally, we demonstrate for the first time that GDF-15 is produced by skeletal muscle cells in response to mitochondrial dysfunction and that its levels correlate in vitro with FGF-21 levels.

A leaky splicing mutation in NFU1 is associated with a particular biochemical phenotype. Consequences for the diagnosis

Mutations in NFU1 were recently identified in patients with fatal encephalopathy. NFU1 is an iron-sulfur cluster protein necessary for the activity of the mitochondrial respiratory chain complexes I-II and the synthesis of lipoic acid. We report two NFU1 compound heterozygous individuals with normal complex I and lipoic acid-dependent enzymatic activities and low, but detectable, levels of lipoylated proteins. We demonstrated a leaky splicing regulation due to a splice site mutation (c.545+5G>A) that produces small amounts of wild type NFU1 mRNA that might result in enough protein to partially lipoylate and restore the activity of lipoic acid-dependent enzymes and the assembly and activity of complex I. These results allowed us to gain insights into the molecular basis underlying this disease and should be considered for the diagnosis of NFU1 patients.

Uses of cancer registries for public health and clinical research in Europe: Results of the European Network of Cancer Registries survey among 161 population-based cancer registries during 2010-2012

AIM

To provide insight into cancer registration coverage, data access and use in Europe. This contributes to data and infrastructure harmonisation and will foster a more prominent role of cancer registries (CRs) within public health, clinical policy and cancer research, whether within or outside the European Research Area.

METHODS

During 2010-12 an extensive survey of cancer registration practices and data use was conducted among 161 population-based CRs across Europe. Responding registries (66%) operated in 33 countries, including 23 with national coverage.

RESULTS

Population-based oncological surveillance started during the 1940-50s in the northwest of Europe and from the 1970s to 1990s in other regions. The European Union (EU) protection regulations affected data access, especially in Germany and France, but less in the Netherlands or Belgium. Regular reports were produced by CRs on incidence rates (95%), survival (60%) and stage for selected tumours (80%). Evaluation of cancer control and quality of care remained modest except in a few dedicated CRs. Variables evaluated were support of clinical audits, monitoring adherence to clinical guidelines, improvement of cancer care and evaluation of mass cancer screening. Evaluation of diagnostic imaging tools was only occasional.

CONCLUSION

Most population-based CRs are well equipped for strengthening cancer surveillance across Europe. Data quality and intensity of use depend on the role the cancer registry plays in the politico, oncomedical and public health setting within the country. Standard registration methodology could therefore not be translated to equivalent advances in cancer prevention and mass screening, quality of care, translational research of prognosis and survivorship across Europe. Further European collaboration remains essential to ensure access to data and comparability of the results.

Follow-up of folinic acid supplementation for patients with cerebral folate deficiency and Kearns-Sayre syndrome

Background

Kearns-Sayre syndrome (KSS) is a mitochondrial DNA deletion syndrome that presents with profound cerebral folate deficiency and other features. Preliminary data support the notion that folinic acid therapy might be useful in the treatment of KSS patients. Our aim was to assess the clinical and neuroimaging outcomes of KSS patients receiving folinic acid therapy.

Methods

Patients: We recruited eight patients with diagnoses of KSS. Four cases were treated at 12 de Octubre Hospital, and the other two cases were treated at Sant Joan de Déu Hospital. Two patients refused to participate in the treatment protocol.

Methods: Clinical, biochemical and neuroimaging data (magnetic resonance imaging or computed tomography scan) were collected in baseline conditions and at different time points after the initiation of therapy. Cerebrospinal fluid 5-methyltetrahydrofolate levels were analysed with HPLC and fluorescence detection. Large-scale mitochondrial DNA deletions were analysed by Southern blot.

Treatment protocol: The follow-up periods ranged from one to eight years. Cases 1–4 received oral folinic acid at a dose of 1 mg/kg/day, and cases 6 and 8 received 3 mg/kg/day.

Results

No adverse effects of folinic acid treatment were observed. Cerebral 5-methyltetrahydrofolate deficiencies were observed in all cases in the baseline conditions. Moreover, all three patients who accepted lumbar puncture after folinic acid therapy exhibited complete recoveries of their decreased basal cerebrospinal fluid 5-methyltetrahydrofolate levels to normal values. Two cases neurologically improved after folinic therapy. Disease worsened in the other patients.

Post-treatment neuroimaging was performed for the 6 cases that received folinic acid therapy. One patient exhibited improvements in white matter abnormalities. The remaining patients displayed progressions in subcortical cerebral white matter, the cerebellum and cerebral atrophy.

Conclusions

Four patients exhibited clinical and radiological progression of the disease following folinic acid treatment. Only one patient who was treated in an early stage of the disease exhibited both neurological and radiological improvements following elevated doses of folinic acid, and an additional patient experienced neurological improvement. Early treatment with high-dose folinic acid therapy seems to be advisable for the treatment of KSS.

Trial registration

EudracT2007-00-6748-23

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-014-0217-2) contains supplementary material, which is available to authorized users.

Association between coenzyme Q10 and glucose transporter (GLUT1) deficiency

Background

It has been demonstrated that glucose transporter (GLUT1) deficiency in a mouse model causes a diminished cerebral lipid synthesis. This deficient lipid biosynthesis could contribute to secondary CoQ deficiency. We report here, for the first time an association between GLUT1 and coenzyme Q₁₀ deficiency in a pediatric patient.

Case presentation

We report a 15 year-old girl with truncal ataxia, nystagmus, dysarthria and myoclonic epilepsy as the main clinical features. Blood lactate and alanine values were increased, and coenzyme Q₁₀ was deficient both in muscle and fibroblasts. Coenzyme Q₁₀ supplementation was initiated, improving ataxia and nystagmus. Since dysarthria and myoclonic epilepsy persisted, a lumbar puncture was performed at 12 years of age disclosing diminished cerebrospinal glucose concentrations. Diagnosis of GLUT1 deficiency was confirmed by the presence of a de novo heterozygous variant (c.18+2T>G) in the SLC2A1 gene. No mutations were found in coenzyme Q₁₀ biosynthesis related genes. A ketogenic diet was initiated with an excellent clinical outcome. Functional studies in fibroblasts supported the potential pathogenicity of coenzyme Q₁₀ deficiency in GLUT1 mutant cells when compared with controls.

Conclusion

Our results suggest that coenzyme Q₁₀ deficiency might be a new factor in the pathogenesis of G1D, although this deficiency needs to be confirmed in a larger group of G1D patients as well as in animal models. Although ketogenic diet seems to correct the clinical consequences of CoQ deficiency, adjuvant treatment with CoQ could be trialled in this condition if our findings are confirmed in further G1D patients.

Vanishing white matter disease in a spanish population

Vanishing white matter (VWM) leukoencephalopathy is one of the most prevalent hereditary white matter diseases. It has been associated with mutations in genes encoding eukaryotic translation initiation factor (eIF2B). We have compiled a list of all the patients diagnosed with VWM in Spain; we found 21 children. The first clinical manifestation in all of them was spasticity, with severe ataxia in six patients, hemiparesis in one child, and dystonic movements in another. They suffered from progressive cognitive deterioration and nine of them had epilepsy too. In four children, we observed optic atrophy and three also had progressive macrocephaly, which is not common in VWM disease. The first two cases were diagnosed before the 1980s. Therefore, they were diagnosed by necropsy studies. The last 16 patients were diagnosed according to genetics: we found mutations in the genes eIF2B5 (13 cases), eIF2B3 (2 cases), and eIF2B4 (1 case). In our report, the second mutation in frequency was c.318A>T; patients with this mutation all followed a slow chronic course, both in homozygous and heterozygous states. Previously, there were no other reports to confirm this fact. We also found some mutations not described in previous reports: c.1090C>T in eIF2B4, c.314A>G in eIF2B5, and c.877C>T in eIF2B5.

Clinical and biochemical outcome after hydroxocobalamin dose escalation in a series of patients with cobalamin C deficiency

BACKGROUND

CblC deficiency produces a combination of methylmalonic aciduria (MMA) and homocystinuria (HCU), and is the most common error of cobalamin metabolism. Patients present a wide spectrum of symptoms, ranging from early severe multisystemic forms, to milder late-onset phenotypes. Cognitive and visual impairment are nearly constant. Hydroxocobalamin (OHCbl), betaine, folinic acid, levocarnitine and eventually dietary protein restriction are the main therapeutic approaches. Although early introduction of OHCbl is crucial, no standardized protocols regarding dose adaptation exist. No reports on long-term outcomes after high doses of this vitamin have been published.

METHODS

In this study five patients with CblC deficiency (early severe forms) were treated with high doses of OHCbl for 18 to 30months. Clinical examinations, neurological assessment, and biochemical studies (plasma total homocysteine (tHcy), amino acids, hydroxocobalamin, and methylmalonic acid in urine) were periodically performed.

RESULTS

Variable clinical and biochemical outcomes were observed in patients treated with high doses of OHCbl. The best biochemical response was observed in those children with the worse metabolic control. By contrast, those patients with a concentration of tHcy around 50μmol/l or less showed only minor changes. Clinically, a considerable improvement was observed in those patients with severe problems in communication, expressive language and behavior.

CONCLUSIONS

According to our study, high OHCbl doses in CblC deficiency could have a greater benefit in those children with a prior history of suboptimal metabolic control, and also in those with severe neurological phenotypes. More specifically, we observed improvements in communication skills and behavior. These results should encourage further prospective trials to determine the optimal OHCbl regimen and to generate protocols and guidelines in this rare disorder.

A profile of hospital consultants: the health practices of a cohort of medical professionals

Personal health practices are important determinants of health. Smoking habits are well documented among doctors. However, alcohol consumption, exercise rates and obesity rates are not. No indigenous studies have been done in this area. This descriptive population study aims to determine these factors. A questionnaire was sent to 381 consultants in hospitals affiliated with UCC Medical School. The response rate was 52.5% (200/381). The smoking rate was 7.5% (15/200) and the alcohol consumption rate was 94% (188/200). Both were more prevalent in females. Over a fifth took no exercise and activity levels were similar between groups. Female consultants were better at weight management than males with a lower proportion over the healthy body mass index (BMI) level. The smoking rate and alcohol consumption rate is higher than other studies. When compared to the general population, doctors are a healthier weight and smoke less but more consultants drink and less exercise regularly.

Serratia entomophila bet gene induction and the impact of glycine betaine accumulation on desiccation tolerance

AIMS

The genes involved in choline transport and oxidation to glycine betaine in the biopesticidal bacterium Serratia entomophila were characterized, and the potential of osmoprotectants, coupled with increased NaCl concentrations, to improve the desiccation tolerance of this species was investigated.

METHODS AND RESULTS

Serratia entomophila carries sequences similar to the Escherichia coli betTIBA genes encoding a choline transporter and dehydrogenase, a betaine aldehyde dehydrogenase and a regulatory protein. Disruption of betA abolished the ability of Ser. entomophila to utilize choline as a carbon source. Quantitative reverse-transcriptase PCR analysis revealed that betA transcription was reduced compared to that of the upstream genes in the operon, and that NaCl and choline induced bet gene expression. Glycine betaine and choline increased the NaCl tolerance of Ser. entomophila, and osmotically preconditioned cultures survived better than control cultures following desiccation and immediately after application to agricultural soil.

CONCLUSIONS

Addition of glycine betaine and NaCl to growth medium can greatly enhance the desiccation survival of Ser. entomophila, and its initial survival in soil.

SIGNIFICANCE AND IMPACT OF THE STUDY

Serratia entomophila is sensitive to desiccation and does not persist under low soil moisture conditions. Techniques described here for enhancing the desiccation survival of Ser. entomophila can be used to improve formulations of this bacterium, and allow its application under a wider range of environmental conditions.

Electrical stunning of pigs: the effect of applied voltage on impedance to current flow and the operation of a fail-safe device

The concept of a 'fail-safe' device to ensure that sufficient current is delivered to render a pig immediately unconscious when electrically stunned was investigated. For live pigs, no significant correlation could be determined between the pre-stun low voltage sensed impedance and the actual, higher voltage stun impedance. In contrast, a good correlation was found using heads from pigs killed more than 24 h previously. The impedance of a live pig's head was predominantly a function of the stunning voltage and decreased non-linearly with increasing voltage. The 'difference' between live and dead pigs was attributed to an 'ageing effect' which is not significant in the first few hours post mortem. No change in phase angle between corresponding stunning current and voltage waveforms, indicated that tissue reactance was not a contributing factor. It is concluded that 'fail-safe' devices based on low voltage pre-stun sensing are unlikely to meet the current legislative requirements (Council Directive 93/119/EC).

Head-only electrical stunning of poultry using a waterbath: a feasibility study

1. The objective of this work was to investigate the feasibility of head only waterbath stunning as a means of generating immediate and long lasting unconsciousness while preventing wing flapping and avoiding carcass damage. 2. EEG measurements showed that immersion of the heads of the broilers for one second in a waterbath containing water of conductivity 2 x 5 mS/cm and a 50 Hz electric field of 10 V/cm resulted in immediate unconsciousness, and that increasing the electric field strength extended the duration of unconsciousness. 3. The passage of a 25-30 mA alternating current of frequency 2000 Hz through the broilers' bodies suppressed the wing flapping that followed a stun. 4. When the body current and electric field were applied simultaneously, wing flapping was prevented and EEG signals were suppressed for over 30 seconds indicating that the immediate unconsciousness lasted long enough to facilitate humane slaughter.

Biochemical parameters to assess choroid plexus dysfunction in Kearns-Sayre syndrome patients

Our aim was to assess biochemical parameters to detect choroid plexus dysfunction in Kearns-Sayre syndrome (KSS) patients. We studied CSF from 7 patients with KSS including total proteins, 5-methyltetrahydrofolate, homovanillic acid (HVA) and Selenium (Se) concentrations. High Se values, increased HVA and total protein concentrations and decreased 5-MTHF values were observed in all cases. This pattern seems very specific to KSS since it was only detected in 7 patients out of 1850 CSF samples analysed, and may represent a good biochemical model for evaluating choroid plexus dysfunction. The accumulated Se in CSF might have deleterious consequences such as toxicity effects.

Serratia entomophilacoated seed to improve ryegrass establishment in the presence of grass grubs

The entomopathogenic bacterium Serratia entomophila is an alternative to chemical control of grass grub (Costelytra zealandica) and is applied in a granule formulation to established pastures Treatment of seed with microbial inoculants is an ideal mechanism for delivery and establishment of microbial control agents into the plant root zone where soil dwelling pests such as grass grub are located Seed treatment with S entomophila was tested in three glasshouse pot trials for its ability to protect germinating ryegrass seedlings from grass grub damage A range of larval densities was used and microbial seed treatment was compared with the insecticide imidacloprid At medium larval densities (equivalent to 70 larvae/m2) use of S entomophilacoated seed resulted in 85 seedling establishment in comparison with 82 emergence from imidaclopridtreated seed At a high larval density of 300/m2 where there was no establishment of untreated seed 3551 of seedlings established from S entomophilatreated seed Results suggest there is potential for seed coating to aid ryegrass establishment in autumnsown pastures

The antecedents of non-affective psychosis in a birth-cohort, with a focus on measures related to cognitive ability, attentional dysfunction and speech problems

OBJECTIVE

Adults with non-affective psychosis show subtle deviations in a range of developmental trajectories as children and adolescents.

METHOD

Based on a birth-cohort (n = 3801), we examined the Peabody Picture Vocabulary Test (PPTV) at age 5, and Raven's Standard Progressive Matrices (RSPM) and Wide Range Achievement Test reading scale (WRAT-R) at age 14. Items related to speech problems and attentional dysfunction were available from maternal- or self-report. At age 21, we identified 60 cohort members who were screen-positive for non-affective psychosis (SP-NAP).

RESULTS

Impaired performance on the PPVT and RSPM (but not WRAT-R) predicted SP-NAP for males only. Male cohort members in the highest quartile for attentional dysfunction at ages 5 and 14 were about 5-8 times more likely to develop SP-NAP. SP-NAP in males was significantly associated with speech problems at age 14.

CONCLUSION

Males who develop non-affective psychoses have subtle impairments in cognitive capacity prior to the development of their psychotic disorder.

Clinical experience with miglustat therapy in pediatric patients with Niemann-Pick disease type C: a case series

Niemann-Pick disease type C (NP-C) is an inherited neurovisceral lysosomal lipid storage disease characterized by progressive neurological deterioration. Different clinical forms have been defined based on patient age at onset: perinatal, early-infantile (EI), late-infantile (Li), juvenile and adult. We evaluated the efficacy and tolerability of miglustat in 16 symptomatic NP-C patients, with comparative reference to one neurologically asymptomatic, untreated patient. All patients were categorized according to age at neurological disease onset, and were assessed using a standardized clinical assessment protocol: disability and cognitive function scales, positron emission tomography (PET), and biochemical markers. PET and disability scale evaluations indicated that cerebral hypometabolism and neurological symptoms were stabilized during treatment in juvenile-onset NP-C patients. EI and Li NP-C patients, who had higher disease severity at baseline (treatment start), showed increased disability scores and progressive cerebral hypometabolism during follow up. Similarly, while cognitive scale scores remained relatively stable in patients with juvenile NP-C, cognition deteriorated in EI and Li patients. Plasma chitotriosidase (ChT) activity was lower in the juvenile NP-C subgroup than in EI and Li patients, and generally increased in patients who discontinued treatment. Plasma CCL18/PARC and ChT activities indicated greater macrophagic activity in EI and Li patients versus juveniles. Miglustat was generally well tolerated; frequent adverse events included diarrhea and flatulence, which were managed effectively by dietary modification and loperamide. Overall, miglustat appeared to stabilize neurological status in juvenile-onset NP-C patients, but therapeutic benefits appeared smaller among younger patients who were at a more advanced stage of disease at baseline.

Axenfeld-Rieger ocular anomaly and retinoblastoma caused by constitutional chromosome 13q deletion

Axenfeld-Rieger (AR) ocular anomaly might be due to deletions of different chromosomes. No association between AR, mental retardation, and retinoblastoma has been described. We report a 2-month-old female with general development delay and dysmorphic features. AR anomaly was detected, and a retinoblastoma (RB) was diagnosed in a very early stage. De novo 13q deletion was identified. Systemic chemotherapy, focal cryotherapy, transpupillary thermotherapy, brachytherapy, and intra-arterial chemotherapy were needed to control the RB. This is the first report of an association of AR, 13q deletion, and retinoblastoma, to be disclosed in patients born with such ocular and dysmorphic features.

Emotional and behavioural antecedents of young adults who screen positive for non-affective psychosis: a 21-year birth cohort study

BACKGROUND

Birth cohort studies have shown that individuals who develop non-affective psychoses display subtle deviations in behaviour during childhood and adolescence. We had the opportunity to examine the widely used Child Behavior Checklist (CBCL) and the Youth Self-Report (YSR) to explore the antecedents of non-affective psychosis.

METHOD

Based on a birth cohort of 3801 young adults, psychopathology was assessed at years 5 and 14 using the CBCL and/or the YSR. Screen-positive non-affective psychosis (SP-NAP) was assessed at year 21 by using the Composite International Diagnostic Interview (CIDI) or a self-report checklist. The association between childhood symptoms and SP-NAP was examined using logistic regression.

RESULTS

Of the cohort, 60 subjects were classified as SP-NAP. In males, SP-NAP was associated with higher scores: (a) on year 5 CBCL 'Total', 'Aggression' and 'Social, Attention and Thought' scores; (b) on year 14 CBCL 'Social', 'Attention' and 'Delinquency' scores, and (c) YSR 'Total' and many YSR subscores. These associations were less clear for females. Hallucinations at year 14 were associated with SP-NAP for both sexes. Boys with high 'Total' scores at both years 5 and 14 were at greatest risk of SP-NAP (a 5-fold risk), followed by boys and girls whose 'Social, Attention and Thought' scores either increased or remained high from years 5 to 14 (3- to 13-fold risk).

CONCLUSIONS

Individuals who screen positive for non-affective psychosis show increased psychopathology during childhood and adolescence. The psychopathological trajectory of children who go on to develop schizophrenia anticipates the heterogeneity associated with the full clinical syndrome.

Demographic correlates of psychotic-like experiences in young Australian adults

OBJECTIVE

Psychotic-like experiences (PLE) in the general community are common. The aims of this study were to examine the prevalence and demographic correlates of PLE in young adults.

METHOD

The sample consisted of 2441 subjects aged 18-23 years. Subjects completed the Composite International Diagnostic Interview (CIDI) and the 21-item Peters Delusional Inventory (PDI). Associations between age, gender, hallucinations and delusions were examined using logistic regression.

RESULTS

Both CIDI hallucinations and delusions predicted high scores on the PDI. Younger age was significantly associated with endorsement of CIDI delusions [odds ratio (OR) = 0.66, 95% confidence interval (CI) 0.48-0.92) and with PDI total scores (OR = 0.68, 95% CI 0.55-0.83). Women were significantly more likely to endorse items related to hallucinations (OR = 1.49, 95% CI 1.14-1.95) but not delusions.

CONCLUSION

PLE are common in young adults. The mechanisms underpinning the age and gender gradients in PLE may provide clues to the pathogenesis of psychotic disorders.

Biochemical and pharmacological characterization of different recombinant acid alpha-glucosidase preparations evaluated for the treatment of Pompe disease

Pompe disease results in the accumulation of lysosomal glycogen in multiple tissues due to a deficiency of acid alpha-glucosidase (GAA). Enzyme replacement therapy for Pompe disease was recently approved in Europe, the U.S., Canada, and Japan using a recombinant human GAA (Myozyme, alglucosidase alfa) produced in CHO cells (CHO-GAA). During the development of alglucosidase alfa, we examined the in vitro and in vivo properties of CHO cell-derived rhGAA, an rhGAA purified from the milk of transgenic rabbits, as well as an experimental version of rhGAA containing additional mannose-6-phosphate intended to facilitate muscle targeting. Biochemical analyses identified differences in rhGAA N-termini, glycosylation types and binding properties to several carbohydrate receptors. In a mouse model of Pompe disease, glycogen was more efficiently removed from the heart than from skeletal muscle for all enzymes, and overall, the CHO cell-derived rhGAA reduced glycogen to a greater extent than that observed with the other enzymes. The results of these preclinical studies, combined with biochemical characterization data for the three molecules described within, led to the selection of the CHO-GAA for clinical development and registration as the first approved therapy for Pompe disease.

Vanishing white matter disease associated with progressive macrocephaly

Vanishing white matter disease (VWM) is one of the most frequent inherited childhood leukoencephalopathies. Five genes have been implicated in this disease ( EIF2B1-5), which encode the five subunits of translation initiation factor eIF2B. The disease has an autosomal recessive mode of inheritance. The age of onset and clinical severity vary widely. The diagnosis is based on magnetic resonance imaging (MRI) findings and is confirmed by molecular studies. We describe an affected female patient with a common and a novel mutation of the EIF2B5 gene, who demonstrated a progressive neurological and radiological deterioration. An unusual feature was her striking macrocephaly. She had an early clinical onset at two years of age and is currently still alive at 26 years of age.