Case report: a novel deep intronic splice-altering variant in DMD as a cause of Becker muscular dystrophy

We present the case of a male patient who was ultimately diagnosed with Becker muscular dystrophy (BMD; MIM# 300376) after the onset of muscle weakness in his teens progressively led to significant walking difficulties in his twenties. A genetic diagnosis was pursued but initial investigation revealed no aberrations in the dystrophin gene (DMD), although immunohistochemistry and Western blot analysis suggested the diagnosis of dystrophinopathy. Eventually, after more than 10 years, an RNA analysis captured abnormal splicing where 154 nucleotides from intron 43 were inserted between exon 43 and 44 resulting in a frameshift and a premature stop codon. Normal splicing of the DMD gene was also observed. Additionally, a novel variant c.6291–13537A>G in DMD was confirmed in the genomic DNA of the patient. The predicted function of the variant aligns with the mRNA results. To conclude, we here demonstrate that mRNA analysis can guide the diagnosis of non-coding genetic variants in DMD

Mapping the Huntington's disease process using cerebrospinal fluid analysis

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder, caused by a CAG-repeat expansion in the HTT-gene. Today there are no disease-modifying therapies (DMTs), but several promising clinical trials are underway, including therapies that reduce mutant huntingtin expression. Reliable biomarkers could empower such trials and guide the timing for initiation of future DMTs. Neurofilament light (NFL) and tau, which are cerebrospinal fluid markers of neuronal death, have been implicated as markers of disease progression. Increased levels of the inflammatory marker YKL-40 have also been reported in HD. The aim was to validate and compare the above biomarker candidates by targeted analyses, while explorative liquid chromatography-mass spectrometry (LC-MS) was used to identify new candidates. Clinically well-characterized HD patients, premanifest gene expansion carriers (pGECs), and controls were enrolled from Uppsala University Hospital in Sweden. In contrast to tau, NFL levels differed between all three groups and NFL had stronger correlations with symptom severity compared with total-tau and phospho-tau. Longitudinally, only NFL maintained intergroup differences and rose with disease progression. Soluble CD27, a marker of T cell-mediated inflammation, differed between all three groups, with the highest levels in manifest HD, and mostly undetectable levels in controls. YKL-40 showed a non-significant trend toward increase in manifest HD.  We applied LC-MS metabolomics and discovered a metabolite signature unique to manifest HD, with deranged tyrosine metabolism including L-DOPA, dopamine, and thyroxine. Utilizing LC-MS we also identified altered proteins in manifest HD, including proenkephalin that was decreased and associated with symptom severity.  In conclusion, NFL may be used as a pharmacodynamic marker in intervention trials. Interestingly, elevated sCD27 implies a role of adaptive immunity before disease onset, but validation is needed. YKL-40 is not suitable as an early marker in HD. The CSF metabolome constitutes a new compartment of potential biomarkers but challenges in metabolite identification should be addressed in future studies. Proenkephalin levels potentially reflect the remaining number of striatal medium spiny neurons and hold promise as a marker of disease progression.

Mapping the Huntington's disease process using cerebrospinal fluid analysis

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder, caused by a CAG-repeat expansion in the HTT-gene. Today there are no disease-modifying therapies (DMTs), but several promising clinical trials are underway, including therapies that reduce mutant huntingtin expression. Reliable biomarkers could empower such trials and guide the timing for initiation of future DMTs. Neurofilament light (NFL) and tau, which are cerebrospinal fluid markers of neuronal death, have been implicated as markers of disease progression. Increased levels of the inflammatory marker YKL-40 have also been reported in HD. The aim was to validate and compare the above biomarker candidates by targeted analyses, while explorative liquid chromatography-mass spectrometry (LC-MS) was used to identify new candidates. Clinically well-characterized HD patients, premanifest gene expansion carriers (pGECs), and controls were enrolled from Uppsala University Hospital in Sweden. In contrast to tau, NFL levels differed between all three groups and NFL had stronger correlations with symptom severity compared with total-tau and phospho-tau. Longitudinally, only NFL maintained intergroup differences and rose with disease progression. Soluble CD27, a marker of T cell-mediated inflammation, differed between all three groups, with the highest levels in manifest HD, and mostly undetectable levels in controls. YKL-40 showed a non-significant trend toward increase in manifest HD.  We applied LC-MS metabolomics and discovered a metabolite signature unique to manifest HD, with deranged tyrosine metabolism including L-DOPA, dopamine, and thyroxine. Utilizing LC-MS we also identified altered proteins in manifest HD, including proenkephalin that was decreased and associated with symptom severity.  In conclusion, NFL may be used as a pharmacodynamic marker in intervention trials. Interestingly, elevated sCD27 implies a role of adaptive immunity before disease onset, but validation is needed. YKL-40 is not suitable as an early marker in HD. The CSF metabolome constitutes a new compartment of potential biomarkers but challenges in metabolite identification should be addressed in future studies. Proenkephalin levels potentially reflect the remaining number of striatal medium spiny neurons and hold promise as a marker of disease progression.

Numerical simulations of the Dynamic Beam Equation in discontinuous media

The study examines the Projection method and the simultaneousapproximation-term (SAT) method as boundary treatment for the dynamic beam equation using summation-by-parts (SBP) operators for handling the inner domain. The methods are examined for both the homogeneous constant coefficient case, and the inhomogeneous piecewise constant coefficient case with a coupled interface. The outer boundaries are handled by SAT or Projection, the coupled interfaced is handled by Projection or a mix between Projection and SAT. Solutions are integrated in time with finite central difference schemes and compared to analytical solutions. A convergence study is conducted with respect to the spatial discretization to measure the accuracy, and the stability is examined by numerical simulations of the CFL-condition. The study shows that Projection has the same accuracy as SAT for most boundary conditions while allowing for a larger timestep. A discontinuity in the medium is found to be handled equally accurate by Projection and the Projection and SAT mixture for all but one case studied, where the mixture was slightly more accurate

Numerical simulations of the Dynamic Beam Equation in discontinuous media

The study examines the Projection method and the simultaneousapproximation-term (SAT) method as boundary treatment for the dynamic beam equation using summation-by-parts (SBP) operators for handling the inner domain. The methods are examined for both the homogeneous constant coefficient case, and the inhomogeneous piecewise constant coefficient case with a coupled interface. The outer boundaries are handled by SAT or Projection, the coupled interfaced is handled by Projection or a mix between Projection and SAT. Solutions are integrated in time with finite central difference schemes and compared to analytical solutions. A convergence study is conducted with respect to the spatial discretization to measure the accuracy, and the stability is examined by numerical simulations of the CFL-condition. The study shows that Projection has the same accuracy as SAT for most boundary conditions while allowing for a larger timestep. A discontinuity in the medium is found to be handled equally accurate by Projection and the Projection and SAT mixture for all but one case studied, where the mixture was slightly more accurate

Psychosis in patients with narcolepsy as an adverse effect of sodium oxybate

AIM: Hypnagogic and hypnopompic hallucinations are characteristic symptoms of narcolepsy, as are excessive daytime sleepiness, cataplexy, and sleep paralysis. Narcolepsy patients may also experience daytime hallucinations unrelated to sleep-wake transitions. The effect of medication on hallucinations is of interest since treatment of narcolepsy may provoke psychotic symptoms. We aim to analyze the relation between sodium oxybate (SXB) treatment and psychotic symptoms in narcolepsy patients. Furthermore, we analyze the characteristics of hallucinations to determine their nature as mainly psychotic or hypnagogic and raise a discussion about whether SXB causes psychosis or if psychosis occurs as an endogenous complication in narcolepsy. METHOD: We present altogether four patients with narcolepsy who experienced psychotic symptoms during treatment with SXB. In addition, we searched the literature for descriptions of hallucinations in narcolepsy and similarities and differences with psychotic symptoms in schizophrenia. RESULTS: Three out of four patients had hallucinations typical for psychosis and one had symptoms that resembled aggravated hypnagogic hallucinations. Two patients also had delusional symptoms primarily associated with mental disorders. Tapering down SXB was tried and helped in two out of four cases. Adding antipsychotic treatment (risperidone) alleviated psychotic symptoms in two cases. CONCLUSION: Psychotic symptoms in narcolepsy may appear during SXB treatment. Hallucinations resemble those seen in schizophrenia; however, the insight that symptoms are delusional is usually preserved. In case of SXB-induced psychotic symptoms or hallucinations, reducing SXB dose or adding antipsychotic medication can be tried

Tau or neurofilament light-Which is the more suitable biomarker for Huntington's disease?

INTRODUCTION:Previous studies have suggested cerebrospinal fluid (CSF) levels of neurofilament light (NFL) and total tau are elevated in Huntington's disease (HD) and may be used as markers of disease stage. Biomarkers are needed due to the slow disease progression and the limitations of clinical assessment. This study aims to validate the role of NFL and tau as biomarkers in HD. METHODS:CSF was obtained from a cohort of HD patients and premanifest HD-mutation carriers. Unified Huntington's Disease Rating Scale (UHDRS) testing was performed on all subjects at the time of sampling. NFL and tau concentrations were determined by ELISA. Spearman correlations were calculated with R version 3.2.3. RESULTS:11 premanifest HD and 12 manifest HD subjects were enrolled. NFL and tau levels were correlated. NFL showed strong correlations with all items included in the clinical assessment (for example the total functional capacity (TFC) (r = - 0.70 p < 0.01) and total motor score (TMS) (r = 0.83p < 0.01). Tau showed slightly weaker correlations (eg. TMS (r = 0.67 p < 0.01); TFC (r = - 0.59 p < 0.01)). NFL was significantly correlated with 5-year probability of disease onset, whereas tau was not. CONCLUSION:This study strengthens the case for NFL as a useful biomarker of disease stage. NFL was strongly correlated to all evaluated items in the UHDRS assessment. Tau also has a potential for use as a biomarker but correlations to clinical tests are weaker in this study. We suggest that NFL and possibly tau be used in clinical drug trials as biomarkers of disease progression that are potentially influenced by future disease-modifying therapies

Huntingtons sjukdom – kliniska prövningar inger nu optimism - Vanligaste formen av ärftlig neurodegenerativ sjukdom i västvärlden ger svåra symtom och förtidig död

Huntington's disease is an autosomal dominant neurodegenerative disease that leads to premature death. The disease is caused by a pathological CAG triplet expansion in the huntingtin gene. The disease is most common in Western populations, with onset in middle age and causing progressive motor, cognitive, and psychiatric symptoms. Currently, only symptomatic treatment is provided, but new molecular technologies may allow treatments reducing levels of mutated huntingtin

Boundary and interface methods for energy stable finite difference discretizations of the dynamic beam equation

We consider energy stable summation by parts finite difference methods (SBP-FD) for the homogeneous and piecewise homogeneous dynamic beam equation (DBE). Previously the constant coefficient problem has been solved with SBP-FD together with penalty terms (SBP-SAT) to impose boundary conditions. In this work, we revisit this problem and compare SBP-SAT to the projection method (SBP-P). We also consider the DBE with discontinuous coefficients and present novel SBP-SAT, SBP-P, and hybrid SBP-SAT-P discretizations for imposing interface conditions. To demonstrate the methodology for two-dimensional problems, we also present a discretization of the piecewise homogeneous dynamic Kirchoff-Love plate equation based on the hybrid SBP-SAT-P method. Numerical experiments show that all methods considered are similar in terms of accuracy, but that SBP-P can be more computationally efficient (less restrictive time step requirement for explicit time integration methods) for both the constant and piecewise constant coefficient problems

Cerebrospinal fluid sCD27 levels indicate active T cell-mediated inflammation in premanifest Huntington's disease

INTRODUCTION: Huntington's disease (HD) is a neurodegenerative disorder, but evidence also suggests neuroinflammation in the pathogenesis. The immune mechanisms involved and the timing of their activation need further clarification. METHODS: A clinically well-characterized HD cohort and gene negative controls were enrolled. YKL-40 reflecting innate immunity and sCD27, a marker of adaptive immunity, were measured across disease stages. Comparisons were made with markers of neurodegeneration: neurofilament light (NFL), total-tau (T-tau), and phospho-tau (P-tau). RESULTS: 52 cross-sectional cerebrospinal fluid samples and 23 follow-up samples were analyzed. sCD27 was elevated in manifest HD and premanifest gene expansion carriers, whereas controls mostly had undetectable levels. YKL-40 showed a trend toward increase in manifest HD. sCD27 correlated with YKL-40 which in turn was closely associated to all included markers of neurodegeneration. YKL-40, NFL, and both forms of tau could all independently predict HD symptoms, but only NFL levels differed between groups after age-adjustment. CONCLUSION: Increased sCD27 in premanifest HD is a sign of T cell-mediated neuroinflammation. This finding is novel since other reports almost exclusively have found early involvement of innate immunity. Validation of sCD27 in a larger HD cohort is needed. The role of adaptive immunity in HD needs further clarification, as it may hasten disease progression