Vidosava Rakocevic-Stojanovic

A retrospective clinical study of the treatment of slow-channel congenital myasthenic syndrome

Slow-channel congenital myasthenic syndrome (CMS) is a rare subtype of CMS caused by dominant “gain of function” mutations in the acetylcholine receptor. Clinically, the cervical and forearm extensor muscles seem to be preferentially weaker; and conventional treatment with anticholinesterases fails to improve symptoms. In contrast, open channel blockers such as fluoxetine and quinidine have been shown to be of benefit. The objectives of our study were to provide further insight into the clinical features of slow-channel CMS and evaluate response to recommended therapy. We carried out a retrospective clinical follow up study of 15 slow-channel CMS patients referred to the Munich CMS Centre. Detailed clinical data were collected by clinicians involved in the care of each patient, with a particular focus on response and tolerability to recommended therapy. Patients varied widely as regard onset of symptoms, severity of disease and mutations involved. Patients received up to four different medications and some had none. Our results strengthen previous reported findings in terms of clinical phenotype variability and the poor response to pyridostigmine. Although treatment with fluoxetine was beneficial in most patients, a number of our patients suffered significant adverse effects that hindered optimum dose titration or led to treatment cessation. Slow-channel CMS is rare and exhibits distinct clinical and genetic characteristics. Our study suggests that fluoxetine, despite being effective in most patients, can be associated with significant side effects, thus reducing treatment effectiveness in clinical practice.

Epidemiological and clinical characteristics of myasthenia gravis in Belgrade, Yugoslavia (1983–1992)

This is the first epidemiological study of myasthenia gravis (MG) in the area of Belgrade. During the survey period (1983–1992), 124 incidental cases of MG were observed, producing an average annual incidence rate of 7.1 per million population (women, 8.3; men, 5.8). Age and sex specific incidence rates for females demonstrated a bimodal pattern, with the first peak in the age group between 20 and 40, and the second peak in the age group 70–80. The age‐specific rates for males showed unimodal pattern, reaching a maximum in the age group between 60 and 80. There was a tendency of more frequent disease appearance in the urban as opposed to the suburban districts. On the prevalence day, December 31, 1992, the point prevalence rate was 121.5 per million (women, 142.5; men, 98.8). Only for incidental cases, the point prevalence rate was 77.1 (women, 83.2; men, 70.4). The average annual mortality rate was 0.47 per million (females, 0.52; males, 0.42), while cumulative lethality was 5.6 (women, 5.6; men, 5.7). Most frequently initial symptoms were ocular, occurring in 58% patients. Through the period of investigation ocular symptoms were generalized in 68%, most frequently in the first 2 years (62.5%). Thymoma was confirmed in 11.3% of patients. In this group there was equal presence of both sexes, older median age at onset, and more severe clinical course of MG. Associated autoimmune disease was found in 17 out of 124 incidental cases (13.7%). The most common were thyroid diseases (7.3%). Family history of MG was recorded in 2 cases belonging to 1 family (1.6%).

Cyclosporine in the treatment of myasthenia gravis

Cyclosporine A (CsA) treatment was evaluated in 52 patients with severe generalized myasthenia gravis (MG) whose illness was not controlled by anticholinesterase drugs, thymectomy, corticosteroids, and azathioprine. The efficacy of CsA treatment was expressed by mean disability score quotient (MDSQ), which was obtained by comparing mean disability score (MDS) at the beginning of the treatment with the MDS at the end of the follow‐up period. For the entire group of patients MDSQ was 53.3%, indicating moderate improvement. Analyzing individual cases, eight patients (15%) did not improve, 17 (33%) showed moderate improvement, 20 (38%) showed remarkable improvement, and seven patients (14%) achieved complete remission. The most common side effects were rise of serum creatinine (seven), hypertension (two), gingival hyperplasia (two), hypertrichosis (six), myalgia (10), and ‘flu‐like’ symptoms (10 patients). The results of this study suggest that CsA is efficacious and safe treatment in severe and resistant forms of MG.

Impairment of cardiac autonomic control in patients with amyotrophic lateral sclerosis

Abstract The aim of this study was to investigate autonomic cardiac control in patients with amyotrophic lateral sclerosis (ALS). Fifty-five patients with sporadic ALS (28 female and 27 male; average age 56.00 ± 10.34 years) were compared to 30 healthy controls (17 female and 13 male; average age 42.87 ± 11.91 years). Patients with previous history of cardiac disease, diabetes mellitus, and impaired respiratory function were excluded from the study. Cardiovascular autonomic tests according to Ewing, power spectrum analysis of RR variability (low- and high-frequency bands – LF and HF, LF/HF index), real-time beat-to-beat ECG signal monitoring with heart rate variability analysis and baroreflex function analysis were carried out in all patients. Time-domain parameters of heart rate variability (mean RR interval, SDNN, SDANN, SDNN index, rMSSD and pNN50%) were obtained from 24-h ECG monitoring. ALS patients had a significantly higher score of sympathetic (p <0.01) and parasympathetic (p <0.001) dysfunction, as well as of the overall score of autonomic dysfunction (p <0.001). LF/HF index was significantly increased; baroreflex sensitivity and time-domain parameters of heart rate variability were highly significantly decreased in ALS patients (p <0.001). Our results demonstrated impaired cardiac autonomic control in ALS with marked parasympathetic dysfunction and sympathetic predominance.

Cognitive Impairment in Myotonic Dystrophy Type 1 Is Associated with White Matter Damage

Objective To investigate grey (GM) and white matter (WM) abnormalities and their effects on cognitive and behavioral deficits in a large, phenotypically and genotypically well-characterized cohort of classic adult (aDM1, age at onset ≥20 years) or juvenile (jDM1, age at onset <20 years) patients with myotonic dystrophy type 1 (DM1). Methods A case-control study including 51 DM1 patients (17 jDM1 and 34 aDM1) and 34 controls was conducted at an academic medical center. Clinical, cognitive and structural MRI evaluations were obtained. Quantitative assessments of regional GM volumes, WM hyperintensities (WMHs), and microstructural WM tract damage were performed. The association between structural brain damage and clinical and cognitive findings was assessed. Results DM1 patients showed a high prevalence of WMHs, severe regional GM atrophy including the key nodes of the sensorimotor and main cognitive brain networks, and WM microstructural damage of the interhemispheric, corticospinal, limbic and associative pathways. WM tract damage extends well beyond the focal WMHs. While aDM1 patients had severe patterns of GM atrophy and WM tract damage, in jDM1 patients WM abnormalities exceeded GM involvement. In DM1, WMHs and microstructural damage, but not GM atrophy, correlated with cognitive deficits. Conclusions WM damage, through a disconnection between GM structures, is likely to be the major contributor to cognitive impairment in DM1. Our MRI findings in aDM1 and jDM1 patients support the hypothesis of a degenerative (premature aging) origin of the GM abnormalities and of developmental changes as the principal substrates of microstructural WM alterations in DM1.

Survival and mortality of myotonic dystrophy type 1 (Steinert's disease) in the population of Belgrade

The purpose of this investigation was to determine survival and mortality in patients with myotonic dystrophy type 1 (DM1) in the Belgrade population within the period from 1983 to 2002. Data of a number of diagnosed DM1 patients with their demographic, clinical and genetic characteristics were gathered from hospital records in all neurologic institutions in Belgrade for the period 1983–2002. Death certificates were reviewed to determine the cause of death. Survival analysis by life table method and Cox proportional hazard model was performed. Within the observed period, in the population of Belgrade, 15 fatal outcomes among 101 patients with DM1 were registered. Average DM1 mortality rate was 0.5/1 000 000 (95% CI 0.3–0.8), and standardized mortality ratio (SMR) was 5.3. A significant inverse correlation was found between age at onset of DM1 and CTG repeats (P = 0.023). The cumulative probability of 15‐year survival for DM1 patients in Belgrade was 49 ± 5% (48 ± 2% for males and 50 ± 7% for females). Younger age at onset was a significant unfavorable prognostic factor (hazard ratio = 4.2; P = 0.012).

Significant impact of behavioral and cognitive impairment on quality of life in patients with myotonic dystrophy type 1.

OBJECTIVE To assess an impact of cognitive and behavioral impairment on QoL in a larger cohort of patients with DM1. METHODS Sixty six genetically confirmed DM1 patients (22 with juvenile (jDM1) and 44 with adult form (aDM1) of the disease) were recruited. Following behavioral tests were used: Hamilton scales for depression and anxiety (HamD and HamA), Daytime Sleepiness Scale (DSS), and Krupps Fatigue Severity Scale (FSS). Patients also underwent detailed classic neuropsychological investigation and Cambridge Neuropsychological Test Automated Battery (CANTAB). Individualized Neuromuscular Quality of Life questionnaire (INQoL) was used as a measure of QoL. RESULTS Patients with jDM1 scored lower than aDM1 patients regarding total INQoL score and all INQoL subdomains, except for myotonia. Significant predictors of total INQoL score in patients with jDM1 were severity of fatigue (β=+0.60, p<0.01) and percentage of correct responses on Spatial Recognition Memory test from CANTAB that measures visuospatial abilities (β=-0.38, p<0.05). The most important predictors of total INQoL score in patients with aDM1 were severity of fatigue (β=+0.36, p<0.05) and level of education (β=-0.29, p<0.05). CONCLUSION Our results showed clear influence of different central manifestations on QoL in patients with both aDM1 and jDM1.

Intergenerational changes of CTG repeat depending on the sex of the transmitting parent in myotonic dystrophy type 1.

Sir, Myotonic dystrophy type 1 (DM1) is an autosomal dominant, multisystemic disease caused by expansion of a CTG repeat, located in the 3¢ untranslated region of dystrophia myotonica protein kinase (DMPK) gene in the chromosome region 19q13.3. Normal DMPK alleles contain between five and 37 copies of the CTG repeat, but this number is greatly increased in DM1 patients. DM1 is the locus that appears to show the most dramatic instability, often with very high levels of somatic mosaicism and very large intergenerational differences. To date, most studies have concentrated on the comparison of blood DNA from patients within families, and the parent–child differences observed defined as intergenerational differences (Harley et al., 1992; Ashizawa et al., 1993; O’Hoy et al., 1993; Martorell et al., 2000). Size of CTG repeat expansion usually increases upon intergeneration transmission and underlies the phenomena of genetic anticipation. However, the reduction in size of the DM1 trinucleotide repeat mutation during transmission is relatively rare. The aim of this study was to analyse the role of parents sex in intergenerational changes of CTG repeats in patients with DM1. Fifty-four DM1 patients (31 males and 23 females), aged between 19 and 51 years (mean ± SD: 36 ± 15), were studied. Diagnosis was based on clinical, electromyographic and genetic examination. Genomic DNA was isolated from white blood cells using proteinase K/SDS digestion and phenol-chloroform extraction. All subjects were studied by both polymerase chain reaction (PCR) and southern blot analyses. All samples showed a series of discrete bands representing somatic mosaicism of diseaseassociated alleles seen in the blood of DM1 patients. The size of each discrete band (expanded allele) was determined according to DNA molecular weight marker, using scatter plot on which band size of DNA marker was plotted against the length to which it migrated in the gel. For each patient the progenitor, the average, and the largest allele was estimated from the lower boundary of the series of discrete bands observed in allele distribution in lymphocytes beyond which rare alleles were detected in repeated analyses. PCR, as previously described (Brook et al., 1992), was performed for precise determination of wild type (wt) DMPK alleles size. Products were resolved on 6% denaturing polyacrylamide gels, detected by silver staining, and a number of CTG repeats was determined using a DNA sequencing ladder. Out of 54 investigated DM1 patients, 30 inherited the DM1 mutation from their mothers and 24 from their affected fathers. Analysis of variance showed that the mean of the smallest CTG expansion (progenitor allele) was smaller in patients with paternal DM1 mutation inheritance (194 ± 113 CTG repeats) than in those with maternal inheritance (292 ± 123 CTG repeats), P < 0.05. The same was found when comparing the means of the average expansions. Conversely, there was no significant influence of parents sex on the value of the largest CTG expansion (P > 0.05), Table 1. We analysed intergenerational changes of the smallest CTG repeats (progenitor alleles) in 20 parent– child pairs (16 mother–child and four father–child pairs). All 16 mother–child pairs exhibited increased CTG repeat expansion in the children (from 63 to 159 CTG repeats in the mothers and 129–596 CTG repeats in the children). A 22-yearold woman exhibited typical clinical signs for juvenile-adult type of DM1 and DMPK expansion range in blood cells from 429 to 900 repeats. As she has a risk of having children affected with congenital type of DM1, she was referred for prenatal diagnosis. CVS sample was taken during gestation week 10, and isolated DNA was tested for DM1 mutation using SP/LR PCR. The CVS sample was contaminated with maternal DNA. Repeated prenatal diagnosis from DNA isolated from amniotic fluid cells revealed the presence of expansion in the range of 2000–3000 CTG repeats. This pregnancy was terminated. From four father–child pairs, we found increased CTG repeat expansion in three pairs, but in one paternal transmission we found reduction (contraction) in size of the CTG repeats (from 113 in the father to 96 in the child). This study shows that maternal transmission of the DM1 mutation results in a greater number of CTG repeats than does paternal transmission. This suggests a greater instability of mutant alleles in female meiosis and predominantly

Cerebrospinal fluid biomarkers of neurodegeneration in patients with juvenile and classic myotonic dystrophy type 1

The aim of the present study was to analyze cerebrospinal fluid (CSF) levels of total tau (T‐tau), phosphorylated tau (P‐tau) and the 42‐amino‐acid form of β‐amyloid (Aβ42) in patients with myotonic dystrophy type 1 (DM1), and their possible correlations with cognitive and behavioral manifestations in these patients.

Cardiac autonomic control in patients with myasthenia gravis and thymoma.

OBJECTIVE To evaluate cardiac autonomic control in patients with myasthenia gravis (MG) and thymoma. MATERIALS AND METHODS The study was performed on 21 patients with MG and thymoma and the same number of matched healthy volunteers. Standard cardiovascular reflex tests according to Ewing and baroreflex sensitivity (BRS) at rest was applied. Spectral analysis of heart rate variability (HRV) at rest was assessed using a 20-minute ECG recording (normalized low- and high-frequency bands-LFnu-RRI, HFnu-RRI and LF/HF-RRI) Time-domain analysis of HRV was derived from 24-hour ECG monitoring. RESULTS Overall autonomic score according to Ewing was significantly increased in patients with MG and thymoma (p<0.05), mostly due to parasympathetic dysfunction. Time-domain parameters representing the overall and long-term sympathetic activity of HRV did not differ significantly between the two groups (p>0.05), but there was a significant decrease in measures of the short-term vagal variations in HRV (p<0.01). HFnu-RRI was lower, while LFnu-RRI and LF/HF-RRI were higher in patients with MG and thymoma in comparison to healthy controls but these differences were not of statistical significance (p>0.05). BRS at rest was highly significantly reduced in patients group (p<0.01). CONCLUSIONS Our results showed mainly parasympathetic cardiac impairment in patients with myasthenia gravis and thymoma. Since autonomic dysfunction may lead to cardiac conduction abnormalities and sudden death, the investigation of autonomic nervous system function in these patients may be significant in everyday clinical practice.