Angela Rosenbohm

Heterozygous R1101K mutation of the DCTN1 gene in a family with ALS and FTD.

A heterozygous R1101K mutation of the p150 subunit of dynactin (DCTN1) is reported in a family with amyotrophic lateral sclerosis (ALS) and co‐occurrence of frontotemporal dementia (FTD). Two members of our kindred were affected with motor neuron disease and two with dementia in an autosomal dominant pattern of inheritance. We excluded the involvement of the ALS and FTD‐linked genes for copper/zinc superoxide dismutase (SOD1) and tau. The R1101K sequence alteration of the DCTN1 gene may predispose subjects to ALS and FTD. Ann Neurol 2005;58:777–780

Neurofilaments in the diagnosis of motoneuron diseases: a prospective study on 455 patients

Objectives Biomarkers for the diagnosis of motoneuron diseases (MND) are urgently needed to improve the diagnostic pathway, patient stratification and monitoring. The aim of this study was to validate candidate markers for MND in cerebrospinal fluid (CSF) and specify cut-offs based on large patient cohorts by especially considering patients who were seen under the initial differential diagnosis (MND mimics). Methods In a prospective study, we investigated CSF of 455 patients for neurofilament light chain (NfL), phosphorylated heavy chain (pNfH), tau protein (Tau) and phospho-tau protein (pTau). Analysed cohorts included patients with apparently sporadic and familial amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) (MND, n=253), MND mimics (n=85) and neurological control groups. Cut-off values were specified, and diagnostic performance and correlation with progression were analysed. Results Nfs were significantly higher in the MND group compared to the control groups, whereas Tau and pTau did not differ. At a cut-off level of 2200 pg/mL for NfL, a 77% diagnostic sensitivity (CI 71% to 82%), 85% specificity (CI 79% to 90%) and 87% positive predictive value (PPV) (CI 81% to 91%) were achieved. For pNfH, we calculated 83% sensitivity (CI 78% to 88%), 77% specificity (CI 71% to 83%) and 82% PPV (CI 77% to 86%) at 560 pg/mL. There were no significant differences between sporadic and genetic ALS or PLS. Nf levels were elevated at early disease stage, and correlated moderately with MND progression and duration. Conclusions Neurofilaments in CSF have a high relevance for the differential diagnosis of MNDs and should be included in the diagnostic work-up of patients. Their value as prognostic markers should be investigated further.

Comparative analysis of brain structure, metabolism, and cognition in myotonic dystrophy 1 and 2

Objective: Myotonic dystrophy type 1 and 2 (DM1/DM2) are multisystemic diseases with common cognitive deficits beside the cardinal muscular symptoms. We performed a comprehensive analysis of cerebral abnormalities to compare the neuropsychological defects with findings in different imaging methods in the same cohort of patients. Methods: Neuropsychological investigations, structural cerebral MRI including brain parenchymal fraction (BPF) and voxel-based morphometry (VBM), and 18F-deoxy-glucose PET (FDG-PET) were performed in patients (20 DM1 and 9 DM2) and matched healthy controls, and analyzed using statistical parametric mapping (SPM2). Results: DM1 and DM2 patients showed typical neuropsychological deficits with a pronounced impairment of nonverbal episodic memory. Both patient groups showed a reduction of the global gray matter (measured by BPF), which could be localized to the frontal and parietal lobes by VBM. Interestingly, VBM revealed a bilateral hippocampal volume reduction that was correlated specifically to both a clinical score and episodic memory deficits. VBM also revealed a pronounced change of thalamic gray matter. White matter lesions were found in >50% of patients and their extent was correlated to psychomotor speed. FDG-PET revealed a frontotemporal hypometabolism, independent of the decrease in cortical gray matter. All abnormalities were similar in both patient groups but more pronounced for DM1. Conclusions: Our results suggest that 1) some of the characteristic cognitive deficits of these patients are linked to specific structural cerebral changes, 2) decreases in gray matter and metabolism are independent processes, and 3) the widespread brain abnormalities are more pronounced in DM1.

Regulation of the human skeletal muscle chloride channel hClC‐1 by protein kinase C

1 The regulation of a recombinant human muscle chloride channel, hClC‐1, by protein kinase C (PKC) was investigated in human embryonic kidney (HEK 293) cells. 2 External application of 4β‐phorbol esters (4β‐PMA) reduced the instantaneous whole‐cell current amplitude over the entire voltage range tested. This effect was abolished when the cells were intracellularly perfused with a specific protein kinase C inhibitor, chelerythine. Inactive 4α‐phorbolesters did not affect the chloride currents. We conclude that the effect of 4β‐phorbol esters is mediated by protein kinase C (PKC). 3 Activation of PKC resulted in changes in macroscopic current kinetics. The time course of current deactivation determined in the presence and absence of 4β‐phorbol esters could be fitted with the sum of two exponentials and a constant value. In the presence of phorbol esters, the fast time constants and the minimum value of the fraction of non‐deactivating current were increased, whereas the voltage dependence of all fractional current amplitudes remained unchanged. PKC‐induced phosphorylation had only small effects on the voltage dependence of the relative open probability and the maximum absolute open probability was unaffected by treatment with 4β‐PMA, as shown by non‐stationary noise analysis. 4 The kinetic changes indicate that phosphorylation alters functional properties of active channels. Since the absolute open probability is not reduced, the observed macroscopic current reduction implies alterations of the ion permeation process. 5 Phosphorylation by PKC appears to affect ion transfer and gating processes. It is postulated that the phosphorylation site may be located at the cytoplasmic vestibule face of the pore.

Quantification of brain atrophy in patients with myotonic dystrophy and proximal myotonic myopathy: a controlled 3-dimensional magnetic resonance imaging study

Myotonic dystrophy (DM1) and proximal myotonic myopathy (PROMM or DM2) are two distinct muscular disorders with multisystemic involvement. Both have previously been reported to be associated with cognitive impairment and white matter lesions detected by cerebral magnetic resonance imaging (MRI). In this study, the extent of brain atrophy was investigated in vivo in ten DM1 and nine PROMM patients in comparison to age-matched healthy controls for each group. The diagnosis was confirmed by DNA analysis of all patients. As a quantitative marker, the ratio of brain parenchymal to intracranial volume, called brain parenchymal fraction (BPF), was calculated from 3-dimensional MRI data using an automated analysis technique. Compared to age-matched healthy controls (mean BPF 0.852 +/- 0.032), the BPF in DM1 patients (0.713 +/- 0.031) was highly significantly decreased (P < 0.001). In contrast, the PROMM patients (mean BPF 0.792 +/- 0.029) showed only slightly decreased BPF values (P < 0.05). BPF was not significantly correlated to any of the clinical or genetic parameters in both diseases (disease duration, motor score, educational level, and number of CTG repeats in the expanded allele). In summary, global brain atrophy was demonstrated to occur in both diseases, but was more severely manifestated in DM1 patients.

Incidence and geographical variation of amyotrophic lateral sclerosis (ALS) in Southern Germany--completeness of the ALS registry Swabia.

Objective of this paper was to investigate the incidence, potential geographical clusters and the completeness of the amyotrophic lateral sclerosis (ALS) registry in Southern Germany (Swabia). Age-standardized incidence rates (ASR) and ratios (SIR) as well as 95% confidence intervals (CI) were estimated at county level. Capture-recapture (CARE) procedures were applied taking data source dependency into account to estimate the quality of case ascertainment in the ALS registry Swabia. We identified 438 ALS cases (53% men, 47% women) in the target population of about 8.4 Mio inhabitants. The gender ratio (men∶women) was 1.1∶1. The mean age at onset of ALS was 63.8 (SD = 11.9) years for men and 66.0 (12.2) for women. The age distribution peaked in the age group 70–74 years. The ASR of ALS was 2.5 per 100,000 person years (PY; 95% CI: 2.3–2.7). The mean SIR was 1.1 per 100,000 PY (95% CI: 1.0–1.2). High SIR suggesting geographical clusters were observed in two counties (Göppingen and Bodenseekreis), but the variation was not statistically significant (p-values = 0.2 and 0.5). The percentage of CARE estimated missing cases was 18.9% in the registry yielding an ASR of 3.1 per 100,000 PY. The high coverage of the CARE estimated completeness of the ALS registry Swabia indicates excellent quality for future projects. Regional variations have to be investigated further.

De novo FUS mutations are the most frequent genetic cause in early-onset German ALS patients.

In amyotrophic lateral sclerosis (ALS) patients with known genetic cause, mutations in chromosome 9 open reading frame 72 (C9orf72) and superoxide dismutase 1 (SOD1) account for most familial and late-onset sporadic cases, whereas mutations in fused in sarcoma (FUS) can be identified in just around 5% of familial and 1% of overall sporadic cases. There are only few reports on de novo FUS mutations in juvenile ALS patients. To date, no systematic evaluation on the frequency of de novo FUS mutations in early-onset ALS patients has been conducted. Here, we screened a cohort of 14 early-onset sporadic ALS patients (onset age <35 years) to determine the frequency of mutations in C9orf72, SOD1, and FUS in this defined patient cohort. All patients were recruited prospectively by a single center in a period of 38 months. No mutations were detected in SOD1 or C9orf72; however, we identified 6 individuals (43%) carrying a heterozygous FUS mutation including 1 mutation that has not been described earlier (c.1504delG [p.Asp502Thrfs*27]). Genetic testing of parents was possible in 5 families and revealed that the mutations in these patients arose de novo. Three of the 6 identified patients presented with initial bulbar symptoms. Our study identifies FUS mutations as the most frequent genetic cause in early-onset ALS. Genetic testing of FUS thus seems indicated in sporadic early-onset ALS patients especially if showing predominant bulbar symptoms and an aggressive disease course.

Implementation of a population-based epidemiological rare disease registry: study protocol of the amyotrophic lateral sclerosis (ALS) - registry Swabia

BackgroundThe social and medical impact of rare diseases is increasingly recognized. Amyotrophic lateral sclerosis (ALS) is the most prevalent of the motor neuron diseases. It is characterized by rapidly progressive damage to the motor neurons with a survival of 2–5 years for the majority of patients. The objective of this work is to describe the study protocol and the implementation steps of the amyotrophic lateral sclerosis (ALS) registry Swabia, located in the South of Germany.Methods/DesignThe ALS registry Swabia started in October 2010 with both, the retrospective (01.10.2008-30.09.2010) and prospective (from 01.10.2010) collection of ALS cases, in a target population of 8.6 million persons in Southern Germany. In addition, a population based case–control study was implemented based on the registry that also included the collection of various biological materials.Retrospectively, 420 patients (222 men and 198 women) were identified. Prospectively data of ALS patients were collected, of which about 70% agreed to participate in the population-based case–control study. All participants in the case–control study provided also a blood sample. The prospective part of the study is ongoing.DiscussionThe ALS registry Swabia has been implemented successfully. In rare diseases such as ALS, the collaboration of registries, the comparison with external samples and biorepositories will facilitate to identify risk factors and to further explore the potential underlying pathophysiological mechanisms.

Amyotrophic lateral sclerosis and denervation alter sphingolipids and up-regulate glucosylceramide synthase

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset disease characterized by upper and lower motor neuron degeneration, muscle wasting and paralysis. Growing evidence suggests a link between changes in lipid metabolism and ALS. Here, we used UPLC/TOF-MS to survey the lipidome in SOD1(G86R) mice, a model of ALS. Significant changes in lipid expression were evident in spinal cord and skeletal muscle before overt neuropathology. In silico analysis also revealed appreciable changes in sphingolipids including ceramides and glucosylceramides (GlcCer). HPLC analysis showed increased amounts of GlcCer and downstream glycosphingolipids (GSLs) in SOD1(G86R) muscle compared with wild-type littermates. Glucosylceramide synthase (GCS), the enzyme responsible for GlcCer biosynthesis, was up-regulated in muscle of SOD1(G86R) mice and ALS patients, and in muscle of wild-type mice after surgically induced denervation. Conversely, inhibition of GCS in wild-type mice, following transient peripheral nerve injury, reversed the overexpression of genes in muscle involved in oxidative metabolism and delayed motor recovery. GCS inhibition in SOD1(G86R) mice also affected the expression of metabolic genes and induced a loss of muscle strength and morphological deterioration of the motor endplates. These findings suggest that GSLs may play a critical role in ALS muscle pathology and could lead to the identification of new therapeutic targets.

Screening for CHCHD10 mutations in a large cohort of sporadic ALS patients: no evidence for pathogenicity of the p.P34S variant

Sir, Bannwarth et al. (2014) reported a mutation in CHCHD10 responsible for a variable phenotype including cerebellar ataxia, hearing impairment, myopathy, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This gene encodes the coiled-coil helix coiled-coil helix domain-containing protein 10 of largely unknown function. It is a strictly mitochondrially located protein that may be involved in respiratory chain function or mitochondrial genome stability (Bannwarth et al. , 2014). Several subsequent publications provided further evidence that CHCHD10 mutations can cause familial motor neuron disease/ALS (familial ALS), with an unusually slow disease progression in most patients (Bannwarth et al. , 2014; Johnson et al. , 2014; Muller et al. , 2014; Kurzwelly et al. , 2015; Penttila et al. , 2015). As an important argument for CHCHD10 causing ALS, co-segregation with disease could be demonstrated for the three CHCHD10 variants p.R15L (Johnson et al. , 2014; Muller et al. , 2014; Kurzwelly et al. , 2015), p.S59L (Bannwarth et al. , 2014) and p.G66V (Penttila et al. , 2015). The strongest genetic evidence for causality exists with regard to the p.G66V mutation, which was first detected by Muller et al. (2014) in a single patient with familial ALS and subsequently shown to co-segregate with a slowly progressing motor neuron disease in a total of 17 pedigrees (Penttila et al. , 2015). Hence there is meanwhile unequivocal evidence that CHCHD10 mutation can cause familial motor neuron degeneration. No association of CHCHD10 variants with ALS could be shown in genome-wide association studies, which can plausibly be explained by the low frequency of CHCHD10 mutations in familial ALS patient cohorts (Bannwarth et al. , 2014; Johnson et al. , 2014; Muller et al. , 2014). Consequently, due to the …