Generation of G51D and 3D mice reveals decreased α-synuclein tetramer-monomer ratios promote Parkinson's disease phenotypes.

Mutations in the α-Synuclein (αS) gene promote αS monomer aggregation that causes neurodegeneration in familial Parkinson's disease (fPD). However, most mouse models expressing single-mutant αS transgenes develop neuronal aggregates very slowly, and few have dopaminergic cell loss, both key characteristics of PD. To accelerate neurotoxic aggregation, we previously generated fPD αS E46K mutant mice with rationally designed triple mutations based on the α-helical repeat motif structure of αS (fPD E46K→3 K). The 3 K variant increased αS membrane association and decreased the physiological tetramer:monomer ratio, causing lipid- and vesicle-rich inclusions and robust tremor-predominant, L-DOPA responsive PD-like phenotypes. Here, we applied an analogous approach to the G51D fPD mutation and its rational amplification (G51D → 3D) to generate mutant mice. In contrast to 3 K mice, G51D and 3D mice accumulate monomers almost exclusively in the cytosol while also showing decreased αS tetramer:monomer ratios. Both 1D and 3D mutant mice gradually accumulate insoluble, higher-molecular weight αS oligomers. Round αS neuronal deposits at 12 mos immunolabel for ubiquitin and pSer129 αS, with limited proteinase K resistance. Both 1D and 3D mice undergo loss of striatal TH+ fibers and midbrain dopaminergic neurons by 12 mos and a bradykinesia responsive to L-DOPA. The 3D αS mice have decreased tetramer:monomer equilibria and recapitulate major features of PD. These fPD G51D and 3D mutant mice should be useful models to study neuronal αS-toxicity associated with bradykinetic motor phenotypes.

Unclassified white matter disorders: A diagnostic journey requiring close collaboration between clinical and laboratory services.

BACKGROUND: Next generation sequencing studies have revealed an ever-increasing number of causes for genetic disorders of central nervous system white matter. A substantial number of disorders are identifiable from their specific pattern of biochemical and/or imaging findings for which single gene testing may be indicated. Beyond this group, the causes of genetic white matter disorders are unclear and a broader approach to genomic testing is recommended. AIM: This study aimed to identify the genetic causes for a group of individuals with unclassified white matter disorders with suspected genetic aetiology and highlight the investigations required when the initial testing is non-diagnostic. METHODS: Twenty-six individuals from 22 families with unclassified white matter disorders underwent deep phenotyping and genome sequencing performed on trio, or larger, family groups. Functional studies and transcriptomics were used to resolve variants of uncertain significance with potential clinical relevance. RESULTS: Causative or candidate variants were identified in 15/22 (68.2%) families. Six of the 15 implicated genes had been previously associated with white matter disease (COL4A1, NDUFV1, SLC17A5, TUBB4A, BOLA3, DARS2). Patients with variants in the latter two presented with an atypical phenotype. The other nine genes had not been specifically associated with white matter disease at the time of diagnosis and included genes associated with monogenic syndromes, developmental disorders, and developmental and epileptic encephalopathies (STAG2, LSS, FIG4, GLS, PMPCA, SPTBN1, AGO2, SCN2A, SCN8A). Consequently, only 46% of the diagnoses would have been made via a current leukodystrophy gene panel test. DISCUSSION: These results confirm the importance of broad genomic testing for patients with white matter disorders. The high diagnostic yield reflects the integration of deep phenotyping, whole genome sequencing, trio analysis, functional studies, and transcriptomic analyses. CONCLUSIONS: Genetic white matter disorders are genetically and phenotypically heterogeneous. Deep phenotyping together with a range of genomic technologies underpin the identification of causes of unclassified white matter disease. A molecular diagnosis is essential for prognostication, appropriate management, and accurate reproductive counseling.

Imaging Patterns Characterizing Mitochondrial Leukodystrophies.

BACKGROUND AND PURPOSE: Achieving a specific diagnosis in leukodystrophies is often difficult due to clinical and genetic heterogeneity. Mitochondrial defects cause 5%-10% of leukodystrophies. Our objective was to define MR imaging features commonly shared by mitochondrial leukodystrophies and to distinguish MR imaging patterns related to specific genetic defects. MATERIALS AND METHODS: One hundred thirty-two patients with a mitochondrial leukodystrophy with known genetic defects were identified in the data base of the Amsterdam Leukodystrophy Center. Numerous anatomic structures were systematically assessed on brain MR imaging. Additionally, lesion characteristics were scored. Statistical group analysis was performed for 57 MR imaging features by hierarchic testing on clustered genetic subgroups. RESULTS: MR imaging features indicative of mitochondrial disease that were frequently found included white matter rarefaction (n = 50 patients), well-delineated cysts (n = 20 patients), T2 hyperintensity of the middle blade of the corpus callosum (n = 85 patients), and symmetric abnormalities in deep gray matter structures (n = 42 patients). Several disorders or clusters of disorders had characteristic features. The combination of T2 hyperintensity in the brain stem, middle cerebellar peduncles, and thalami was associated with complex 2 deficiency. Predominantly periventricular localization of T2 hyperintensities and cystic lesions with a distinct border was associated with defects in complexes 3 and 4. T2-hyperintense signal of the cerebellar cortex was specifically associated with variants in the gene NUBPL. T2 hyperintensities predominantly affecting the directly subcortical cerebral white matter, globus pallidus, and substantia nigra were associated with Kearns-Sayre syndrome. CONCLUSIONS: In a large group of patients with a mitochondrial leukodystrophy, general MR imaging features suggestive of mitochondrial disease were found. Additionally, we identified several MR imaging patterns correlating with specific genotypes. Recognition of these patterns facilitates the diagnosis in future patients.

Degeneration alters the biomechanical properties and structural composition of lateral human menisci.

OBJECTIVE: Because the literature relating to the influence of degeneration on the viscoelasticity and tissue composition of human lateral menisci remains contradictory or completely lacking, the aim of this study was to fill these gaps by comprehensively characterising the biomechanical properties of menisci with regard to the degree of degeneration. DESIGN: Meniscal tissue from 24 patients undergoing a total knee replacement was collected and the degeneration of each region classified according to Pauli et al. For biomechanical characterisation, compression and tensile tests were performed. Additionally, the water content was determined and infrared (IR) spectroscopy was applied to detect changes in the structural composition, particularly of the proteoglycan and collagen content. RESULTS: With an increasing degree of degeneration, a significant decrease of the equilibrium modulus was detected, while simultaneously the water content and the hydraulic permeability significantly increased. However, the tensile modulus displayed a tendency to decrease with increasing degeneration, which might be due to the significantly decreasing amount of collagen content identified by the IR measurements. CONCLUSION: The findings of the current study may contribute to the understanding of meniscus degeneration, showing that degenerative processes appear to mainly worsen viscoelastic properties of the inner circumference by disrupting the collagen integrity.

Oculodentodigital Dysplasia: A Hypomyelinating Leukodystrophy with a Characteristic MRI Pattern of Brain Stem Involvement.

Oculodentodigital dysplasia, a rare genetic disorder caused by mutations in the gene encoding gap junction protein 1, classically presents with typical facial features, dental and ocular anomalies, and syndactyly. Oligosymptomatic patients are common and difficult to recognize, in particular if syndactyly is absent. Neurologic manifestation occurs in approximately 30% of patients, and leukodystrophy or T2 hypointensity of gray matter structures or both have been noted in individual patients. To investigate MR imaging changes in oculodentodigital dysplasia, we retrospectively and systematically reviewed 12 MRIs from 6 genetically confirmed patients. Diffuse supratentorial hypomyelination, T2-hypointense Rolandic and primary visual cortex, and symmetric involvement of middle cerebellar peduncle, pyramidal tract, and medial lemniscus was present in all, T2-hypointense pallidum and dentate nucleus in 2 patients each. This consistent, characteristic pattern of diffuse supratentorial hypomyelination and brain stem involvement differs from other hypomyelinating and nonhypomyelinating leukodystrophies with brain stem involvement, and its recognition should trigger genetic testing for oculodentodigital dysplasia.

Non-motor symptoms and quality of life in dopa-responsive dystonia patients.

BACKGROUND: In patients with GTP-cyclohydrolase deficient dopa-responsive dystonia (DRD) the occurrence of associated non-motor symptoms (NMS) is to be expected. Earlier studies report conflicting results with regard to the nature and severity of NMS. The aim of our study was to investigate the prevalence of psychiatric disorders, sleep problems, fatigue and health-related quality of life (HR-QoL) in a Dutch DRD cohort. METHODS: Clinical characteristics, motor symptoms, type and severity of psychiatric co-morbidity, sleep problems, fatigue and HR-QoL were assessed in DRD patients with a confirmed GCH1 mutation and matched controls. RESULTS: Twenty-eight patients were included (18 adults and 10 children), from 10 families. Dystonia symptoms were well-controlled in all patients. According to the DSM IV patients significantly more often met the criteria for a lifetime psychiatric disorder than controls (61% vs. 29%, p < 0.05). In particular the frequencies of generalized anxiety and agoraphobia were higher in patients (both 29% vs. 4%, p < 0.05). Patients scored significantly higher on daytime sleepiness than controls (ESS, 11.2 vs 5.7, p < 0.05). Adult patients had significantly lower scores on the mental component of the HR-QoL (47 vs. 54, p < 0.05) than controls mainly associated with (worse) quality of sleep. CONCLUSION: NMS were highly prevalent in our cohort of DRD patients, despite adequate treatment of motor symptoms. Our findings support the accumulating evidence of an important non-motor phenotype in DRD, with possible involvement of serotonergic mechanisms. This highlights the need to address NMS and the underlying neurobiology in patients with DRD.

Effects of short and prolonged transcutaneous vagus nerve stimulation on heart rate variability in healthy subjects.

The vagus nerve is strategically located in the body, and has multiple homeostatic and health-promoting effects. Low vagal activity predicts onset and progression of diseases. These are the reasons to activate this nerve. This study examined the effects of transcutaneous vagus nerve stimulation (t-VNS) on a main index of vagal activity, namely heart rate variability (HRV). In Study 1, we compared short (10min) left versus right ear t-VNS versus sham (no stimulation) in a within-subjects experimental design. Results revealed significant increases in only one HRV parameter (standard deviation of the RR intervals (SDNN)) following right-ear t-VNS. Study 2 examined the prolonged effects of t-VNS (1h) in the right ear. Compared to baseline, right-t-VNS significantly increased the LF and LF/HF components of HRV, and SDNN in women, but not in men. These results show limited effects of t-VNS on HRV, and are discussed in light of neuroanatomical and statistical considerations and future directions are proposed.

Retrospective evaluation of low long-term efficacy of antiepileptic drugs and ketogenic diet in 39 patients with CDKL5-related epilepsy.

OBJECTIVE: Mutations in the CDKL5 gene cause an early-onset epileptic encephalopathy. To date, little is known about effective antiepileptic treatment in this disorder. METHOD: Accordingly, the aim of this retrospective study was to explore the role of different antiepileptic drugs (AEDs) and the ketogenic diet (KD) in the treatment of this rare genetic disorder. We evaluated the efficacy in 39 patients with CDKL5 mutations at 3, 6 and 12 months after the introduction of each treatment. One patient was lost to follow-up after 6 and 12 months. RESULTS: The responder rate (>50% reduction in seizure frequency) to at least one AED or KD was 69% (27/39) after 3 months, 45% (17/38) after 6 months and 24% (9/38) after 12 months. The highest rate of seizure reduction after 3 months was reported for FBM (3/3), VGB (8/25), CLB (4/17), VPA (7/34), steroids (5/26), LTG (5/23) and ZNS (2/11). Twelve patients (31%) experienced a seizure aggravation to at least one AED. Most patients showed some but only initial response to various AEDs with different modes of actions. SIGNIFICANCE: Considering both age-related and spontaneous fluctuation in seizure frequency and the unknown impact of many AEDs or KD on cognition, our data may help defining realistic treatment goals and avoiding overtreatment in patients with CDKL5 mutations. There is a strong need to develop new treatment strategies for patients with this rare mutation.

Long-term outcome of children with patent processus vaginalis incidentally diagnosed by laparoscopy.

INTRODUCTION: Patent processus vaginalis (PPV) might be incidentally diagnosed during laparoscopy. The aims of this study were to determine the prevalence and the natural history of PPV, i.e. its possible development into symptomatic inguinal hernia. INCLUSION CRITERIA: children <16years undergoing laparoscopy for pathologies other than processus vaginalis (PV) related, from 10/2000-10/2005. EXCLUSION CRITERIA: past or present history of PV-related pathologies. The internal inguinal rings were documented during laparoscopy. Follow-up was provided by phone inquiry and clinical examination if needed. Median follow-up was 10.5years (range 7.1-12.8). RESULTS: 416 patients were included. Median age at laparoscopy was 12.4years (range 3days-18.1years). Forty-three PPV (33 unilateral, 5 bilateral) were found in 38 patients (9.1%). Four children with PPV presented later with an ipsilateral inguinal hernia (10.5%, 95%CI [3%; 25%]), at a median age of 16.0years (range 11.8-17.3), at a median of 22.5months (range 12-50) after initial laparoscopy, as compared to no patient in the population with obliterated PV (0%, 95%CI [0%; 1%]). CONCLUSION: 9.1% of the observed pediatric population showed an asymptomatic PPV, and 10.5% of these children later developed an inguinal hernia. None of the children with obliterated PV developed a hernia.

Pediatric neurocysticercosis: three cases presented in the Netherlands with divergent clinical presentations.

BACKGROUND: Neurocysticercosis is a helminthic disease that affects the central nervous system by the larvae of the Taenia solium, the pork tapeworm. Because of the growing number of immigrants from endemic areas, its incidence is increasing in Western Europe. CASES: We describe three children, aged between 2 and 13 years, two of whom have a definite and one a probable diagnosis of neurocysticercosis based on the "Del Brutto criteria." They presented with different symptoms and signs: symptomatic epilepsy, asymmetric cerebral palsy, and headache. Serological evaluation was negative in two of the three cases. All cases showed comparable abnormalities on magnetic resonance imaging of the brain: solitary or multiple, cystic lesions, with surrounding edema. In one of them, the "scolex" (part of the larvae) could be visualized. One case was treated with albendazole, the other two cases did not receive medication. CONCLUSION: A prompt diagnosis of neurocysticercosis by recognition of its typical brain lesions is important to prevent unnecessary diagnostic tests and treatment.

Hypertrophic intraventricular flow obstruction after very-low-dose dexamethasone (Minidex) in preterm infants: case presentation and review of the literature.

The use of dexamethasone in preterm infants developing bronchopulmonary dysplasia has been proven to be effective. Hypertrophic cardiomyopathy is a frequently reported, although transient, side effect of high-dose dexamethasone administration. The recent introduction of very low dexamethasone dose, called 'Minidex', promised equal effectiveness compared to high-dose dexamethasone without relevant side effects. Our study presents two patients developing hypertrophic cardiomyopathy with intraventricular cardiac obstruction after administration of 'Minidex'. Marked cardiac side effects may occur even during very-low-dose dexamethasone treatment in preterm neonates. Betablocker and discontinuation of dexamethasone seem to allow spontaneous reversal of myocardial hypertrophy and obstruction. After all, systematic surveys of the incidence of cardiac complications in a larger population of preterm infants treated with very low doses of dexamethasone are needed.

Revisiting default mode network function in major depression: evidence for disrupted subsystem connectivity.

BACKGROUND: Major depressive disorder (MDD) is characterized by alterations in brain function that are identifiable also during the brain's 'resting state'. One functional network that is disrupted in this disorder is the default mode network (DMN), a set of large-scale connected brain regions that oscillate with low-frequency fluctuations and are more active during rest relative to a goal-directed task. Recent studies support the idea that the DMN is not a unitary system, but rather is composed of smaller and distinct functional subsystems that interact with each other. The functional relevance of these subsystems in depression, however, is unclear. METHOD: Here, we investigated the functional connectivity of distinct DMN subsystems and their interplay in depression using resting-state functional magnetic resonance imaging. RESULTS: We show that patients with MDD exhibit increased within-network connectivity in posterior, ventral and core DMN subsystems along with reduced interplay from the anterior to the ventral DMN subsystems. CONCLUSIONS: These data suggest that MDD is characterized by alterations of subsystems within the DMN as well as of their interactions. Our findings highlight a critical role of DMN circuitry in the pathophysiology of MDD, thus suggesting these subsystems as potential therapeutic targets.

MRI as diagnostic tool in early-onset peroxisomal disorders.

OBJECTIVE: Peroxisomal blood tests are generally considered to be conclusive. We observed several patients with a clinical and MRI phenotype suggestive of an infantile onset peroxisomal defect, but no convincing abnormalities in initial peroxisomal blood tests. Brain MRI showed typical abnormalities as observed in the neonatal adrenoleukodystrophy variant of infantile peroxisomal disorders. Our aim was to evaluate the accuracy of this MRI diagnosis with further peroxisomal testing. METHODS: We searched our database of unclassified leukoencephalopathies and found 6 such patients. We collected clinical data and scored available MRIs of these patients. We performed further peroxisomal studies in fibroblasts, including immunofluorescence microscopy analysis with antibodies against catalase, a peroxisomal matrix enzyme. We performed complementation analysis and analyzed the suspected genes. RESULTS: We confirmed the diagnosis of Zellweger spectrum disorder in 3 patients and D-bifunctional protein deficiency in the others. The clinical findings were within the spectrum known for these diagnoses. Sequential MRIs showed that the abnormalities started in the hilus of the dentate nucleus and superior cerebellar peduncles. Subsequently, the cerebellar white matter and brainstem tracts were affected, followed by the parieto-occipital white matter, splenium of the corpus callosum, and posterior limb of the internal capsule. Eventually, all cerebral white matter became abnormal. The thalamus was typically affected as well. CONCLUSIONS: If MRI reveals abnormalities suggestive of infantile onset peroxisomal defects, negative peroxisomal blood tests do not exclude the diagnosis. Further tests in fibroblasts should be performed, most importantly immunofluorescence microscopy analysis with antibodies against catalase to stain peroxisomes.

Quality of life after restorative proctocolectomy and ileal pouch-anal anastomosis in patients with familial adenomatous polyposis: a matter of adjustment.

AIM: Favourable outcomes for health-related quality of life (HRQL) have been reported in patients with familial adenomatous polyposis (FAP) after restorative proctocolectomy and ileal pouch-anal anastomosis (RPC). However, less is known about patients' subjective experience and adjustment to postoperative impairment. Using a multidimensional psychometric assessment, we investigated patient-reported HRQL to determine the impact of the patient's subjective experience together with medical, functional and psychosocial factors on HRQL. METHOD: In this cross-sectional study, 116 FAP patients who had undergone RPC on average 8 years earlier completed standardized and study-specific questionnaires and participated in a personal interview. The impact of medical, functional and psychosocial factors on patients' HRQL was determined by regression analyses. RESULTS: When using a generic psychometric measure, FAP patients' overall HRQL was comparable with that of the general population. Impaired HRQL, however, was found in patients reporting poor pouch function in contrast to those reporting good or moderate functional outcome. Findings from a personalized interview also suggested that a good functional result does not necessarily translate into good HRQL. Personal resources predicted patients' physical and psychological well-being, whereas little variance of HRQL was explained by medical factors and function. CONCLUSION: Patients' HRQL is, to a substantial degree, the result of adjustment to the adverse impact of RPC. By using personal resources the majority of patients may achieve satisfactory HRQL levels even when bowel function is impaired. A multidimensional assessment that comprises medical, functional and psychosocial aspects is required to ascertain an adequate evaluation of FAP patients after RPC.

N-acetylaspartylglutamate in CNS hypomyelination.

CSF N-acetylaspartylglutamate (NAAG) has been found to be elevated in some hypomyelinating disorders. This study addressed the question whether it could be used as a marker for hypomyelination and as a means to distinguish between hypomyelinating disorders biochemically. We have measured CSF NAAG in a cohort of 28 patients with hypomyelination with known and unknown aetiology. NAAG was found to be elevated in 7 patients, but was normal in the majority, including patients with defined hypomyelinating disorders. CSF NAAG is not a universal marker of hypomyelination, and the mechanism of its elevation remains poorly understood.

[Pharmacotherapeutic treatment strategies for smoking cessation]. / Pharmakologische Strategien zur Unterstützung einer Raucherentwöhnung.

Regular tobacco smoking occurs in about 35% of the male and 25% of the female German population. Individual attempts to independently quit smoking and to remain abstinent for 1 year have been shown to be successful in less than 5% of cases. This rate can be doubled by means of individual consulting and cognitive-behavioral interventions and additional pharmacological treatment might increase abstinence rates up to 25%. Apart from nicotine substitution (e.g. transdermal, oral and inhalative applications) and bupropion, recent studies have shown beneficial effects of varenicline for smoking cessation and abstinence. Varenicline, a selective partial nicotinergic agonist, has been specifically developed for the purpose of smoking cessation. Currently available data suggest that varenicline is more effective compared to nicotine substitution therapy and bupropion, increasing the abstinence likelihood by a factor of 2.3 compared to a placebo. Recent data regarding anti-nicotine vaccines suggest that this approach might yield a comparable treatment outcome and probably even better relapse-preventing effects than conventional psychopharmacological strategies. The first anti-nicotine vaccines are expected to be approved by national authorities within the forthcoming 1-2 years.

The liver X receptor (LXR) and its target gene ABCA1 are regulated upon low oxygen in human trophoblast cells: a reason for alterations in preeclampsia?

OBJECTIVES: The Liver X receptors (LXR) alpha and beta and their target genes such as the ATP-binding cassette (ABC) transporters have been shown to be crucially involved in the regulation of cellular cholesterol homeostasis. The aim of this study was to characterize the role of LXR alpha/beta in the human placenta under normal physiological circumstances and in preeclampsia. STUDY DESIGN: We investigated the expression pattern of the LXRs and their target genes in the human placenta during normal pregnancy and in preeclampsia. Placental explants and cell lines were studied under different oxygen levels and pharmacological LXR agonists. MAIN OUTCOME MEASURES: Gene expressions (Taqman PCR) and protein levels (Western Blot) were combined with immunohistochemistry to analyze the expression of LXR and its target genes. RESULTS: In the human placenta, LXRA and LXRB expression increased during normal pregnancy. This was paralleled by the expression of their prototypical target genes, e.g., the cholesterol transporter ABCA1. Interestingly, early-onset preeclamptic placentae revealed a significant upregulation of ABCA1. Culture of JAr trophoblast cells and human first trimester placental explants under low oxygen lead to increased expression of LXRA and ABCA1 which was further enhanced by the LXR agonist T0901317. CONCLUSIONS: LXRA together with ABCA1 are specifically expressed in the human placenta and can be regulated by hypoxia. Deregulation of this system in early preeclampsia might be the result of placental hypoxia and hence might have consequences for maternal-fetal cholesterol transport.

Elevated CSF N-acetylaspartylglutamate in patients with free sialic acid storage diseases.

OBJECTIVE: To investigate body fluids of patients with undiagnosed leukodystrophies using in vitro (1)H-NMR spectroscopy (H-NMRS). METHODS: We conducted a cross-sectional study using high-resolution in vitro H-NMRS on CSF and urine samples. RESULTS: We found a significant increase of free sialic acid in CSF or urine in 6 of 41 patients presenting with hypomyelination of unknown etiology. Molecular genetic testing revealed pathogenic mutations in the SLC17A5 gene in all 6 patients. H-NMRS revealed an increase of N-acetylaspartylglutamate in the CSF of all patients with SLC17A5 mutation (range 13-114 micromol/L, reference <12 micromol/L). CONCLUSION: In patients with undiagnosed leukodystrophies, increased free sialic acid in CSF or urine is a marker for free sialic acid storage disorder and facilitates the identification of the underlying genetic defect. Because increase of N-acetylaspartylglutamate in CSF has been observed in other hypomyelinating disorders, it can be viewed as a marker of a subgroup of hypomyelinating disorders.