Christine I. Dali

Metachromatic leukodystrophy: natural course of cerebral MRI changes in relation to clinical course.

ObjectiveMetachromatic Leukodystrophy (MLD) is a rare disorder leading to demyelination and neurological impairment. A natural history study within the German leukodystrophy network analyzed MRI changes with respect to the clinical course.Methods113 MR images of 68 patients (33 late-infantile, 35 juvenile) were studied cross-sectionally and longitudinally. MRI and motor deterioration were assessed using standardized scoring systems.ResultsThe temporal and spatial patterns of MR severity scores differed between the late-infantile and juvenile form. Although early (involving central white matter, corpus callosum) and late signs (involving pons, cerebellum, cerebral atrophy) were similar, high MRI scores (mean 18, SD 1.2, p < 0.001) were evident in the juvenile form already at the onset of first symptoms and even in presymptomatic patients. The progression rate of the MRI score was clearly higher and more uniform in the late-infantile (on average 8 per year, p < 0.0001) than in the juvenile patients (on average 0.4 per year, p < 0.08). In late-infantile patients, MRI changes correlated highly with motor deterioration (rho = 0.73, p < 0.001), this was less remarkable in the juvenile form (rho = 0.50, p < 0.01). Severe motor dysfunction was associated with U-fiber involvement and cerebellar changes (p < 0.05).ConclusionsMRI showed a typical spatial pattern, which evolved gradually and uniformly during disease progression in late-infantile MLD. In juvenile MLD MRI changes were already observed at disease onset and temporal patterns were more variable. As therapeutic options for MLD are evolving, these findings are not only important for patient counseling but also for the evaluation of therapeutic interventions.

Brain N-acetylaspartate levels correlate with motor function in metachromatic leukodystrophy

Background: Late infantile metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disorder that causes severe demyelination of the nervous system. The neuronal metabolite N-acetylaspartate (NAA) serves as a source of acetyl groups for myelin lipid synthesis in oligodendrocytes and is known as a marker for neuronal and axonal loss. NAA and other metabolite levels measured by proton magnetic resonance spectroscopy (MRS) correlate with performance of the brain in normal children. There is a need for sensitive measures of disease progression in patients with MLD to enable development of future treatments. Methods: A cross-section of 13 children with late infantile MLD were examined by proton MRS. Signals from NAA, total choline, and total creatine in the deep white matter were measured and correlated with the results of cognitive and motor function tests. Results: The NAA signal decreased as the disease process advanced. Motor function, measured by the Gross Motor Function Measure–88, varied from 13 (only head movement in the supine position) to 180 (able to walk) across the study cohort, demonstrating a wide range in functional status. Similarly, varied decreases were observed in cognitive function. We report strong positive correlations between standardized measures of motor and cognitive function and NAA levels in the deep white matter. Conclusions: We suggest that NAA levels could serve as a sensitive biomarker in children with MLD. Proton MRS may provide a valuable tool for measuring the effects of treatment interventions in this disorder.

Cerebral gray and white matter changes and clinical course in metachromatic leukodystrophy

Objective: Metachromatic leukodystrophy (MLD) is a rare metabolic disorder leading to demyelination and rapid neurologic deterioration. As therapeutic options evolve, it seems essential to understand and quantify progression of the natural disease. The aim of this study was to assess cerebral volumetric changes in children with MLD in comparison to normal controls and in relation to disease course. Method: Eighteen patients with late-infantile MLD and 42 typically developing children in the same age range (20–59 months) were analyzed in a cross-sectional study. Patients underwent detailed genetic, biochemical, electrophysiologic, and clinical characterization. Cerebral gray matter (GM) and white matter (WM) volumes were assessed by multispectral segmentation of T1- and T2-weighted MRI. In addition, the demyelinated WM (demyelination load) was automatically quantified in T2-weighted images of the patients, and analyzed in relation to the clinical course. Results: WM volumes of patients did not differ from controls, although their growth curves were slightly different. GM volumes of patients, however, were on average 10.7% (confidence interval 6.0%–14.9%, p < 0.001) below those of normally developing children. The demyelination load (corrected for total WM volume) increased with disease duration (p < 0.003) and motor deterioration (p < 0.001). Conclusion: GM volume in patients with MLD is reduced when compared with healthy controls, already at young age. This supports the notion that, beside demyelination, neuronal dysfunction caused by neuronal storage plays an additional role in the disease process. The demyelination load may be a useful noninvasive imaging marker for disease progression and may serve as reference for therapeutic intervention.

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.

Sulfatide levels correlate with severity of neuropathy in metachromatic leukodystrophy.

Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disorder due to deficient activity of arylsulfatase A (ASA) that causes accumulation of sulfatide and lysosulfatide. The disorder is associated with demyelination and axonal loss in the central and peripheral nervous systems. The late infantile form has an early‐onset, rapidly progressive course with severe sensorimotor dysfunction. The relationship between the degree of nerve damage and (lyso)sulfatide accumulation is, however, not established.

The ethical framework for performing research with rare inherited neurometabolic disease patients

AbstractThe need for performing clinical trials to develop well-studied and appropriate medicines for inherited neurometabolic disease patients faces ethical concerns mainly raising from four aspects: the diseases are rare; include young and very young patients; the neurological impairment may compromise the capability to provide ‘consent’; and the genetic nature of the disease leads to further ethical implications. This work is intended to identify the ethical provisions applicable to clinical research involving these patients and to evaluate if these cover the ethical issues. Three searches have been performed on the European regulatory/legal framework, the literature and European Union-funded projects. The European legal framework offers a number of ethical provisions ruling the clinical research on paediatric, rare, inherited diseases with neurological symptoms. In the literature, relevant publications deal with informed consent, newborn genetic screenings, gene therapy and rights/interests of research participants. Additional information raised from European projects on sharing patients’ data from different countries, the need to fill the gap of the regulatory framework and to improve information to stakeholders and patients/families. Conclusion: Several recommendations and guidelines on ethical aspects are applicable to the inherited neurometabolic disease research in Europe, even though they suffer from the lack of a common ethical approach.What is Known:• When planning and conducting clinical trials, sponsors and researchers know that clinical trials are to be performed according to well-established ethical rules, and patients should be aware about their rights.• In the cases of paediatric patients, vulnerable patients unable to provide consent, genetic diseases’ further rules apply.What is New:• This work discusses which ethical rules apply to ensure protection of patient’s rights if all the above-mentioned features coexist.• This work shows available data and information on how these rules have been applied.

Alpha-mannosidosis: correlation between phenotype, genotype and mutant MAN2B1 subcellular localisation

BackgroundAlpha-mannosidosis is caused by mutations in MAN2B1, leading to loss of lysosomal alpha-mannosidase activity. Symptoms include intellectual disabilities, hearing impairment, motor function disturbances, facial coarsening and musculoskeletal abnormalities.MethodsTo study the genotype-phenotype relationship for alpha-mannosidosis 66 patients were included. Based on the predicted effect of the mutations and the subcellular localisation of mutant MAN2B1 in cultured cells, the patients were divided into three subgroups.Clinical and biochemical data were collected. Correlation analyses between each of the three subgroups of genotype/subcellular localisation and the clinical and biochemical data were done to investigate the potential relationship between genotype and phenotype in alpha-mannosidosis.Statistical analyses were performed using the SPSS software. Analyses of covariance were performed to describe the genotype-phenotype correlations. The phenotype parameters were modelled by the mutation group and age as a covariate. P values of <0.05 were considered as statistically significant.ResultsComplete MAN2B1 genotypes were established for all patients. We found significantly higher scores in the Leiter-R test, lower concentrations of CSF-oligosaccharides, higher point scores in the Bruininks-Oseretsky Test of Motor Proficiency subtests (BOT-2); Upper limb coordination and Balance, and a higher FVC% in patients in subgroup 3, harbouring at least one variant that allows localisation of the mutant MAN2B1 protein to the lysosomes compared to subgrou 2 and/or subgroup 1 with no lysosomal localization of the mutant MAN2B1 protein.ConclusionOur results indicate a correlation between the MAN2B1 genotypes and the cognitive function, upper limb coordination, balance, FVC% and the storage of oligosaccharides in CSF. This correlation depends on the subcellular localisation of the mutant MAN2B1 protein.

Alpha-mannosidosis: characterization of CNS pathology and correlation between CNS pathology and cognitive function

Alpha‐mannosidosis (AM) (OMIM 248500) is a rare lysosomal storage disease. The understanding of the central nervous system (CNS) pathology is limited. This study is the first describing the CNS pathology and the correlation between the CNS pathology and intellectual disabilities in human AM. Thirty‐four patients, aged 6–35 years, with AM were included. Data from 13 healthy controls were included in the analysis of the magnetic resonance spectroscopy (MRS). Measurements of CNS neurodegeneration biomarkers in cerebrospinal fluid (CSF), CSF‐oligosaccharides, and performance of cerebral magnetic resonance imaging (MRI) and MRS were carried out. On MRI, 5 of 10 patients had occipital white matter (WM) signal abnormalities, and 6 of 10 patients had age‐inappropriate myelination. MRS demonstrated significantly elevated mannose complex in gray matter and WM. We found elevated concentrations of tau‐protein, glial fibrillary acidic protein and neurofilament light protein in 97 patients, 74% and 41% of CSF samples, respectively. A negative correlation between CSF‐biomarkers and cognitive function and CSF‐oligosaccharides and cognitive function was found. The combination of MRS/MRI changes, elevated concentrations of CSF‐biomarkers and CSF‐oligosaccharides suggests gliosis and reduced myelination, as part of the CNS pathology in AM. Our data demonstrate early neuropathological changes, which may be taken into consideration when planning initiation of treatment.

Anesthesia for patients with alpha-mannosidosis – a case series of 10 patients

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Annual severity increment score as a tool for stratifying patients with Niemann-Pick disease type C and for recruitment to clinical trials

BackgroundNiemann-Pick disease type C (NPC) is a lysosomal storage disease with a heterogeneous neurodegenerative clinical course. Multiple therapies are in clinical trials and inclusion criteria are currently mainly based on age and neurological signs, not taking into consideration differential individual rates of disease progression.ResultsIn this study, we have evaluated a simple metric, denoted annual severity increment score (ASIS), that measures rate of disease progression and could easily be used in clinical practice. We show that ASIS is stable over several years and can be used to stratify patients for clinical trials. It achieves greater homogeneity of the study cohort relative to age-based inclusion and provides an evidence-based approach for establishing inclusion/exclusion criteria. In addition, we show that ASIS has prognostic value and demonstrate that treatment with an experimental therapy - acetyl-DL-leucine - is associated with a reduction in ASIS scores.ConclusionASIS has the potential to be a useful metric for clinical monitoring, trial recruitment, for prognosis and measuring response to therapy.