Friedrich Asmus

Hertie-Institute for Clinical Brain Research, Tübingen, Baden-Württemberg, Germany

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Publications (46)329.16 Total impact

  • Oliver Kaut, Friedrich Asmus, Sebastian Paus
    Movement Disorders 08/2012; 27(10):1327-8. · 5.63 Impact Factor
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    ABSTRACT: Sporadic, genetically complex essential tremor (ET) is one of the most common movement disorders and may lead to severe impairment of the quality of life. Despite high heritability, the genetic determinants of ET are largely unknown. We performed the second genome-wide association study (GWAS) for ET to elucidate genetic risk factors of ET. Using the Affymetrix Genome-Wide SNP Array 6.0 (1000K) we conducted a two-stage GWAS in a total of 990 subjects and 1,537 control subjects from Europe to identify genetic variants associated with ET. We discovered association of an intronic variant of the main glial glutamate transporter (SLC1A2) gene with ET in the first-stage sample (rs3794087, p = 6.95 × 10(-5), odds ratio [OR] = 1.46). We verified the association of rs3794087 with ET in a second-stage sample (p = 1.25 × 10(-3), OR = 1.38). In the subgroup analysis of patients classified as definite ET, rs3794087 obtained genome-wide significance (p = 3.44 × 10(-10), OR = 1.59) in the combined first- and second-stage sample. Genetic fine mapping using nonsynonymous single nucleotide polymorphisms (SNPs) and SNPs in high linkage disequilibrium with rs3794087 did not reveal any SNP with a stronger association with ET than rs3794087. We identified SLC1A2 encoding the major glial high-affinity glutamate reuptake transporter in the brain as a potential ET susceptibility gene. Acute and chronic glutamatergic overexcitation is implied in the pathogenesis of ET. SLC1A2 is therefore a good functional candidate gene for ET.
    Neurology 07/2012; 79(3):243-8. · 8.30 Impact Factor
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    Movement Disorders 06/2011; 26(11):2136-7. · 5.63 Impact Factor
  • European Journal of Neurology 02/2011; · 4.16 Impact Factor
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    ABSTRACT: No clinical disorders have been caused by dysfunction of any of the 5 subtypes (M1-M5) of muscarinic receptors. We present a patient with a novel clinical syndrome that we suggest results from a deficiency of the muscarinic M3 receptor. We conducted a comprehensive workup of autonomic function. The patient's disorder was compared to the phenotypic features of male M3 knockout mice. M3 protein quantity was assessed by Western blot and radioligand binding in peripheral blood lymphocytes. Tests for autoantibodies and genetic abnormalities were performed. The disease pattern was characterized by disturbances in micturition, pupil constriction, body weight, and sudomotor function, with normal accommodation, gastrointestinal motility, salivation, and lacrimation, similar to features of male M3 knockout mice. M3 protein quantity was reduced. Genetic tests were unrevealing, but unspecific antinuclear antibodies were present. The presented clinical syndrome suggests a deficiency of the muscarinic M3 receptor. These results and future evaluation of patients with autonomic deficits may provide insights into the site and functional role of the muscarinic M3 receptor in humans.
    Neurology 02/2011; 76(5):451-5. · 8.30 Impact Factor
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    ABSTRACT: OBJECTIVES: to provide a revised version of earlier guidelines published in 2006. BACKGROUND: primary dystonias are chronic and often disabling conditions with a widespread spectrum mainly in young people. DIAGNOSIS: primary dystonias are classified as pure dystonia, dystonia plus or paroxysmal dystonia syndromes. Assessment should be performed using a validated rating scale for dystonia. Genetic testing may be performed after establishing the clinical diagnosis. DYT1 testing is recommended for patients with primary dystonia with limb onset before age 30, and in those with an affected relative with early-onset dystonia. DYT6 testing is recommended in early-onset or familial cases with cranio-cervical dystonia or after exclusion of DYT1. Individuals with early-onset myoclonus should be tested for mutations in the DYT11 gene. If direct sequencing of the DYT11 gene is negative, additional gene dosage is required to improve the proportion of mutations detected. A levodopa trial is warranted in every patient with early-onset primary dystonia without an alternative diagnosis. In patients with idiopathic dystonia, neurophysiological tests can help with describing the pathophysiological mechanisms underlying the disorder. TREATMENT: botulinum toxin (BoNT) type A is the first-line treatment for primary cranial (excluding oromandibular) or cervical dystonia; it is also effective on writing dystonia. BoNT/B is not inferior to BoNT/A in cervical dystonia. Pallidal deep brain stimulation (DBS) is considered a good option, particularly for primary generalized or cervical dystonia, after medication or BoNT have failed. DBS is less effective in secondary dystonia. This treatment requires a specialized expertise and a multidisciplinary team.
    European Journal of Neurology 01/2011; 18(1):5-18. · 4.16 Impact Factor
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    ABSTRACT: Progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are progressive disabling neurological conditions usually fatal within 10 years of onset. Little is known about the economic costs of these conditions. This paper reports service use and costs from France, Germany and the UK and identifies patient characteristics that are associated with cost. 767 patients were recruited, and 760 included in the study, from 44 centres as part of the NNIPPS trial. Service use during the previous six months was measured at entry to the study and costs calculated. Mean six-month costs were calculated for 742 patients. Data on patient sociodemographic and clinical characteristics were recorded and used in regression models to identify predictors of service costs and unpaid care costs (i.e., care from family and friends). The mean six-month service costs of PSP were €24,491 in France, €30,643 in Germany and €25,655 in the UK. The costs for MSA were €28,924, €25,645 and €19,103 respectively. Unpaid care accounted for 68-76%. Formal and unpaid costs were significantly higher the more severe the illness, as indicated by the Parkinson's Plus Symptom scale. There was a significant inverse relationship between service and unpaid care costs.
    PLoS ONE 01/2011; 6(9):e24369. · 3.53 Impact Factor
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    Movement Disorders 10/2010; 25(14):2472-5. · 5.63 Impact Factor
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    ABSTRACT: Involuntary eyelid closure (IEC) may occur after deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson's disease (PD) and is often categorised as apraxia of lid opening (ALO), albeit the appropriateness of this term is under debate. To gain insight into the hitherto undefined pathophysiology of IEC after STN-DBS, we performed a comprehensive clinical and electrophysiological characterisation of lid function in a total of six PD patients. The study was carried out in six PD patients who developed IEC after STN-DBS. They underwent neurological examination and electromyography recording of activity in the orbicularis oculi muscle (OO) upon varying stimulation patterns. Intraoperative studies were performed in one patient. Increasing STN-DBS intensity induced IEC in four patients, whereas it improved the condition in two. Needle EMG showed tonic hyperactivity of the OO in STN-DBS induced IEC, while variable patterns of OO activity (irregular and tonic) were seen in patients with STN-DBS-relieved IEC. Intraoperative analysis in one patient showed evidence for IEC being induced by activation of corticobulbar fibres. We identified two groups of IEC after STN-DBS based on clinical and EMG patterns: (1) STN-DBS induced IEC associated with tonic OO overactivity and (2) STN-DBS relieved IEC presenting with variable EMG patterns. Our findings provide relevant information on pathophysiology of STN-DBS related IEC and implications for its therapeutic management.
    Journal of neurology, neurosurgery, and psychiatry 09/2010; 81(9):1002-7. · 4.87 Impact Factor
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    ABSTRACT: Deep brain stimulation (DBS) of the internal globus pallidus (GPi) and ventral intermediate thalamic nucleus (VIM) are established treatment options in primary dystonia and tremor syndromes and have been reported anecdotally to be efficacious in myoclonus-dystonia (MD). We investigated short- and long-term effects on motor function, cognition, affective state, and quality of life (QoL) of GPi- and VIM-DBS in MD. Ten MD-patients (nine epsilon-sarcoglycan-mutation-positive) were evaluated pre- and post-surgically following continuous bilateral GPi- and VIM-DBS at four time points: presurgical, 6, 12, and as a last follow-up at a mean of 62.3 months postsurgically, and in OFF-, GPi-, VIM-, and GPi-VIM-DBS conditions by validated motor [unified myoclonus rating scale (UMRS), TSUI Score, Burke-Fahn-Marsden dystonia rating scale (BFMDRS)], cognitive, affective, and QoL-scores. MD-symptoms significantly improved at 6 months post-surgery (UMRS: 61.5%, TSUI Score: 36.5%, BFMDRS: 47.3%). Beneficial effects were sustained at long-term evaluation post-surgery (UMRS: 65.5%, TSUI Score: 35.1%, BFMDRS: 48.2%). QoL was significantly ameliorated; affective status and cognition remained unchanged postsurgically irrespective of the stimulation conditions. No serious long-lasting stimulation-related adverse events (AEs) were observed. Both GPi- and VIM-DBS offer equally effective and safe treatment options for MD. With respect to fewer adverse, stimulation-induced events of GPi-DBS in comparison with VIM-DBS, GPi-DBS seems to be preferable. Combined GPi-VIM-DBS can be useful in cases of incapaciting myoclonus, refractory to GPi-DBS alone.
    Movement Disorders 08/2010; 25(11):1733-43. · 5.63 Impact Factor
  • F Asmus, T Gasser
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    ABSTRACT: Dystonia-plus syndromes represent a heterogeneous group of diseases, where dystonia is accompanied by other neurological features and gene mutations can be detected frequently. Symptomatic dystonias and complex neurodegenerative diseases with dystonia as part of the clinical presentation are excluded from this category. At present, the following disorders are categorized as dystonia-plus syndromes: Dopa-responsive dystonia (DRD) is a mostly pediatric-onset, neurometabolic disorder with two different modes of inheritance: in its autosomal-dominant form, heterozygous mutations of GTP-cyclohydrolase I (GCH1, DYT5) cause DRD with reduced penetrance and excellent and lasting response to levodopa. Autosomal-recessive (AR) forms of DRD are caused by homozygous or compound heterozygous mutations of the tyrosine hydroxylase (TH) or the sepiapterin reductase (SPR) gene. In AR-DRD, the phenotype is generally more severe including cognitive deficits and developmental delay. Diagnosis can be confirmed by analysis of CSF pterine metabolites. Alternatively, comprehensive genetic testing yields causative mutations in up to 80% of patients. Myoclonus-dystonia (M-D) is caused by heterozygous mutations of the epsilon-sarcoglycan gene (SGCE). Dystonia is generally only mild to moderate, and 'lightning-like' myoclonic jerks occur rarely at rest and can be triggered by complex motor tasks like writing and drawing. Both features together with an age at onset below 25 years strongly predict SGCE mutation in M-D and differentiate this genetic disease from other 'jerky' dystonias. The combination of dystonia and parkinsonism can only be rarely observed in non-degenerative syndromes. Besides DRD, two additional syndromes have been classified. Rapid-onset dystonia-parkinsonism (RPD, DYT12) is a rare disorder with an abrupt onset of symptoms over minutes to days, prominent bulbar involvement and parkinsonism with a lack of response to levodopa. Patients with this rare phenotype should be screened for mutation in the Na(+)/K(+) ATPase alpha3-subunit (ATP1A3) gene, even if family history is negative. Recently, a novel form of dystonia-parkinsonism (DYT16) has been found to be linked to mutations in the PRKRA gene, whose relation to basal ganglia disorders is yet unknown .
    European Journal of Neurology 07/2010; 17 Suppl 1:37-45. · 4.16 Impact Factor
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    Movement Disorders 12/2009; 25(2):243-5. · 5.63 Impact Factor
  • Neurology 08/2009; 73(4):328; author reply 328-9. · 8.30 Impact Factor
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    ABSTRACT: We identified a marker in LINGO1 showing genome-wide significant association (P = 1.2 x 10(-9), odds ratio = 1.55) with essential tremor. LINGO1 has potent, negative regulatory influences on neuronal survival and is also important in regulating both central-nervous-system axon regeneration and oligodendrocyte maturation. Increased axon integrity observed in Lingo1 mouse [corrected] knockout models highlights the potential role of LINGO1 in the pathophysiology of ET [corrected]
    Nature Genetics 03/2009; 41(3):277-9. · 35.21 Impact Factor
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    ABSTRACT: Hyperkinetic dystonia is characterized by phasic, tremulous, and "jerky" movements in addition to twisting postures. We studied longitudinally 23 index patients with hyperkinetic dystonia from a quaternary pediatric movement disorder clinic in Ireland. Four clinical categories emerged: (1) Eight patients were diagnosed with myoclonus-dystonia, of whom seven carried heterozygous epsilon sarcoglycan (SGCE) mutations, including a novel deletion of exon 10. Gait disorder, unsteadiness, or frequent falls before 18 months were detected in all SGCE mutation carriers, whereas the typical neck-predominant presentation developed only years later. (2) One patient classified as benign hereditary chorea, because jerks were choreiform and continuous rather than action-induced, carried a heterozygous stop mutation of the TITF-1 gene (Y114X, exon 2). (3) Three mutation-negative patients were grouped as "myoclonic dystonia" with jerks only in the body regions affected by dystonia. (4) Eleven patients presented with a novel combination of dystonia and low amplitude poly-mini myoclonus of the upper limbs and pectoral muscles (D-PMM). In early childhood up to 3 years of age, an initial presentation with predominant gait impairment with only subtle jerks should prompt consideration of SGCE mutation analysis in addition to testing for DYT1 mutations. A causative gene for D-PMM remains to be identified.
    Movement Disorders 01/2009; 24(5):702-9. · 5.63 Impact Factor
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    ABSTRACT: Sensory gestes (SG) are a pathognomonic sign of dystonia, which can be detected in up to two thirds of patients with cervical dystonia (CD). They reduce dystonia severity markedly but transiently. We report a patient whose CD substantially worsened with sensory input to the back of the head and neck in different body postures, a phenomomen recently termed "reverse" sensory geste (rSG) in craniocervical dystonia. In a cohort of CD outpatients, screening for "reverse" effects of SG on dystonia yielded a prevalence of 12.8% (n = 6/47). The most frequent rSG pattern was increased dystonic activity in a supine, resting position while trying to fall asleep. The response to rSG persisted throughout the course of the disease arguing for an impairment of central integration of neck proprioception. Assessment of rSG should be included in the routine examination of CD patients, since BTX treatment may have to beadjusted accordingly to be efficacious.
    Movement Disorders 01/2009; 24(2):297-300. · 5.63 Impact Factor
  • Neurology 09/2008; 71(9):695. · 8.30 Impact Factor
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    ABSTRACT: Mutations in the epsilon-sarcoglycan gene (SGCE) can cause autosomal dominant inherited myoclonus-dystonia (M-D). Defects in other sarcoglycans; alpha-, beta-, gamma-, and delta can cause autosomal recessive inherited limb girdle muscular dystrophies. epsilon- and alpha-sarcoglycans are very homologous and may substitute for one-another in different tissues. We therefore investigated whether mutations in SGCE also cause abnormalities of skeletal and myocardial muscle. Six patients with clinically and genetically verified M-D and no signs of limb-girdle muscular dystrophy were included. Skeletal muscle biopsies were obtained from all patients, and endomyocardial muscle biopsy from one of the patients. Morphological and immunohistological investigations were performed and compared with controls. Histological and immunohistological investigations of muscle and clinical assessment of muscle strength and mass showed no difference between M-D patients and controls. Our findings indicate that patients with M-D have no signs or symptoms of muscle disease. This suggests a different role of the sarcoglycan complex epsilonbetagammadelta versus alphabetagammadelta complex in humans, as earlier suggested in rodents.
    European Journal of Neurology 06/2008; 15(5):525-9. · 4.16 Impact Factor
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    ABSTRACT: Camptocormia is characterized by an abnormal posture of the trunk with pronounced flexion of the thoraco-lumbar spine during standing and walking, which abates in a supine position. Treatment options for camptocormia are limited and mostly futile. Here, we report on the ultrasound-guided ventral injection of botulinum toxin A (BTX) into deep portions of the iliopsoas muscle in four parkinsonian patients with camptocormia as chief complaint. Using this novel and safe application technique, all patients received 500-1,500 MU of BTX per side in 4-6 month intervals. Treatment was generally well tolerated. At the highest dose, all patients complained of mild weakness of hip flexion. Standardized physical exam at follow-up visits, as well as self-assessment of patients, failed to show a relevant and lasting improvement of posture. In conclusion, injection of BTX into the iliopsoas does not appear to be a promising approach for the treatment of parkinsonism-associated camptocormia.
    Movement Disorders 05/2008; 23(6):889-92. · 5.63 Impact Factor
  • Klinische Neurophysiologie 12/2007; 38(04). · 0.33 Impact Factor

Publication Stats

2k Citations
329.16 Total Impact Points

Institutions

  • 2004–2012
    • Hertie-Institute for Clinical Brain Research
      Tübingen, Baden-Württemberg, Germany
  • 2003–2010
    • University of Tuebingen
      • Hertie Institute for Clinical Brain Research
      Tübingen, Baden-Württemberg, Germany
  • 2001–2006
    • Ludwig-Maximilian-University of Munich
      • Department of Neurology
      München, Bavaria, Germany