Quick scheme for evaluation of atomic charges in arbitrary aluminophosphate sieves on the basis of electron densities calculated with DFT methods.

It is demonstrated that unique and simple analytical functions are justified for the atomic charge dependences q of the T (T = Al, P) and O atoms of aluminophosphates (AlPOs) using DFT calculations with several basis sets, starting from STO-3G to 3-21G and 6-21G**. Three internal (bonds, angles, ...) coordinates for the charge dependences of the T atoms and four coordinates for the O are sufficient to reach a precision of 1.8% for the fitted q(Al), 1.0% for q(P), and 2.5% for q(O) relatively to the values calculated at any basis set level. The proposed strategy consists in an iterative scheme starting from charge dependences based on the neighbor's positions only. Electrostatic potential values are computed to illustrate the differences between the calculated and fitted charges in the considered AlPO models.

[Neuromuscular diseases 2: muscular dystrophies (MD)]. / Neuromuskuläre Erkrankungen (NME).

Traditionally, muscular dystrophies (MDs) are progressive, hereditary, and primarily degenerative myopathies. Nowadays, due to molecular biology, MDs are looked upon as clinically and genetically heterogeneous myopathies characterized by protein defects of muscle tissue resulting most often in muscle weakness. They are caused by gene mutations leading to a decrease of structural proteins or enzymes. The site of the primary defect and the protein function are different. The disorders are defined according to the underlying protein defect (dystrophinopathy, calpainopathy, and others). The gene or gene product are not yet known in all forms of MD (for example, facioscapulohumeral muscular dystrophy). Therefore, the nomenclature based on the protein defects and the term MD are used concurrently. Clinical symptoms, pathogenesis, diagnosis, therapy, prognosis, and possible prevention of the more frequent MDs are discussed: dystrophinopathies (Duchenne, Becker type), Emery-Dreifuss syndrome (3 forms), facioscapulohumeral MD, limb-girdle MD (17 forms), myotonic dystrophies (2 forms), and congenital MD (11 forms). This article highlights the significance of molecular analyses and the possible multisystemic symptoms in these myopathies.

[Neuromuscular diseases (NME). I. Spinal muscular atrophy, peripheral nerve diseases, congenital myasthenia gravis]. / Neuromuskuläre Erkrankungen (NME). Teil 1: Spinale Muskelatrophien, periphere Nervenerkrankungen, kongenitale myasthene Syndrome.

Among the group of clinically and genetically heterogeneous spinal muscular atrophies(SMA), the autosomal recessive proximal types I-III are the most frequent. They are caused by mutations of the telomeric copy of the survival motor neuron gene (SMN1) on chromosome sq while loss of the centromeric copy (SMN2) does not lead to SMA. The conservation of exon 7 in the SMN2 copy seems to be crucial for possible causal therapy options. The genetic defect is also known for spinal muscular atrophy with respiratory distress. Hereditary polyneuropathies are caused by mutations in several genes on different chromosomes. Genetic and phenotypic heterogeneity must be considered. Data on clinical symptoms, inheritance, and neurophysiology are obligatory for the most effective molecular analysis. Hereditary congenital myasthenic syndromes are clinically, genetically, and pathogenetically heterogeneous. The diagnostic significance of molecular genetic analyses is still increasing. Therapeutic options include oral medication and assisted ventilation as needed.

Rapsyn N88K is a frequent cause of congenital myasthenic syndromes in European patients.

BACKGROUND: Mutations in various genes of the neuromuscular junction may cause congenital myasthenic syndromes (CMS). Most mutations identified to date affect the epsilon-subunit gene of the acetylcholine receptor (AChR), leading to end-plate AChR deficiency. Recently, three different mutations in the RAPSN gene have been identified in four CMS patients with AChR deficiency. OBJECTIVE: To perform mutation analysis of the RAPSN gene in patients with sporadic or autosomal recessive CMS. METHODS: One hundred twenty CMS patients from 110 unrelated families were analyzed for the RAPSN mutation N88K by restriction fragment length polymorphism and sequence analysis. RESULTS: In 12 CMS patients from 10 independent families, RAPSN N88K was identified either homozygous or heteroallelic to another missense mutation. Symptoms usually started perinatally or in the first years of life. However, one patient did not show any myasthenic symptoms before the third decade. Clinical symptoms typically included bilateral ptosis, weakness of facial, bulbar, and limb muscles, and a favorable response to anticholinesterase treatment. Crisis-like exacerbations with respiratory insufficiency provoked by stress, fever, or infections in early childhood were frequent. All RAPSN N88K families originate from Central or Western European countries. Genotype analysis indicated that they derive from a common ancestor (founder). CONCLUSIONS: The RAPSN mutation N88K is a frequent cause of rapsyn-related CMS in European patients. In general, patients (RAPSN N88K) were characterized by mild to moderate myasthenic symptoms with favorable response to anticholinesterase treatment. However, severity and onset of symptoms may vary to a great extent.

A G468-T AMPD1 mutant allele contributes to the high incidence of myoadenylate deaminase deficiency in the Caucasian population.

Myoadenylate deaminase deficiency is the most common metabolic disorder of skeletal muscle in the Caucasian population, affecting approximately 2% of all individuals. Although most deficient subjects are asymptomatic, some suffer from exercise-induced myalgia suggesting a causal relationship between a lack of enzyme activity and muscle function. In addition, carriers of this derangement in purine nucleotide catabolism may have an adaptive advantage related to clinical outcome in heart disease. The molecular basis of myoadenylate deaminase deficiency in Caucasians has been attributed to a single mutant allele characterized by double C to T transitions at nucleotides +34 and +143 in mRNA encoded by the AMPD1 gene. Polymerase chain reaction-based strategies have been developed to specifically identify this common mutant allele and are considered highly sensitive. Consequently, some laboratories preferentially use this technique over other available diagnostic tests for myoadenylate deaminase deficiency. We previously identified a G468-T mutation in one symptomatic patient who was only heterozygous for the common AMPD1 mutant allele. In this report, nine additional individuals with this compound heterozygous genotype are revealed in a survey of 48 patients with documented deficiency of skeletal muscle adenosine monophosphate deaminase and exercise-induced myalgia. Western blot analysis of leftover biopsy material from one of these individuals does not detect any immunoreactive myoadenylate deaminase polypeptide. Baculoviral expression of the G468-T mutant allele produces a Q156H substitution enzyme exhibiting labile catalytic activity. These combined results demonstrate that the G468-T transversion is dysfunctional and further indicate that AMPD1 alleles harboring this mutation contribute to the high incidence of partial and complete myoadenylate deaminase deficiency in the Caucasian population. Consequently, genetic tests for abnormal AMPD1 expression designed to diagnose patients with metabolic myopathy, and to evaluate genetic markers for clinical outcome in heart disease should not be based solely on the detection of a single mutant allele.

Alpha-sarcoglycanopathy previously misdiagnosed as Duchenne muscular dystrophy: implications for current diagnostics and patient care.

Differential diagnosis of limb-girdle muscular dystrophy, including alpha-sarcoglycanopathy and Duchenne muscular dystrophy, is impossible to acheive on clinical grounds alone; therefore immunohistology, Western blotting and molecular genetic analysis are manadatory for a correct diagnosis. The patient's genotype with a hitherto unknown mutation (Tyr134STOP) in exon 5 adds to the growing spectrum of mutations in the alpha-sarcoglycan gene.

Mutations in CAV3 cause mechanical hyperirritability of skeletal muscle in rippling muscle disease.

Hereditary rippling muscle disease (RMD) is an autosomal dominant human disorder characterized by mechanically triggered contractions of skeletal muscle. Genome-wide linkage analysis has identified an RMD locus on chromosome 3p25. We found missense mutations in positional candidate CAV3 (encoding caveolin 3; ref. 5) in all five families analyzed. Mutations in CAV3 have also been described in limb-girdle muscular dystrophy type 1C (LGMD1C; refs. 6,7), demonstrating the allelism of dystrophic and non-dystrophic muscle diseases.

Isolated loss of gamma-sarcoglycan: diagnostic implications in autosomal recessive limb-girdle muscular dystrophies.

Mutations in the sarcoglycan (SG) genes cause a subset of limb-girdle muscular dystrophies (LGMD). We report a Spanish patient with progressive LGMD exhibiting an almost isolated loss of gamma-SG and a homozygous Delta521-T mutation in the gamma-SG gene. These results suggest that isolated loss of gamma-SG might remain undetected using only the alpha-SG antibody in routine muscle biopsy studies. Both alpha- and gamma-SG antibodies should be used in the diagnostic detection of patients with LGMD.

A sporadic case of rippling muscle disease caused by a de novo caveolin-3 mutation.

OBJECTIVE: To determine the cause of sporadic rippling muscle disease (RMD) in a 24-year-old patient. BACKGROUND: RMD is a rare myopathy characterized by percussion-induced rapid muscle contractions (PIRC), muscle mounding, and rippling waves. We have recently found that autosomal dominant RMD is caused by mutations in the caveolin-3 gene (CAV3) on chromosome 3p25. Possibly, increased activity of neuronal nitric oxide synthase (nNOS) contributes to the clinical characteristics of increased mechanical muscle hyperexcitability. METHODS: Clinical examination, mutational analysis, and immunohistochemistry of muscle tissue were performed in a patient with sporadic RMD. RESULTS: The authors observed a de novo CAV3 missense mutation Arg26Gln. Immunohistochemistry showed reduced caveolin-3 surface expression in a muscle biopsy. In addition, the authors found normal sarcolemmal nNOS expression and a reduced expression of alpha-dystroglycan in muscle fibers. CONCLUSIONS: These data confirm that RMD is caused by CAV3 mutations. Moreover, there is evidence that CAV3 mutations may also be found in patients without a positive family history of RMD.

Long-Term Steroid Therapy in Duchenne Muscular Dystrophy-Positive Results versus Side Effects.

PURPOSE: In tins retrospective study, positive results and side effects of long-term steroid treatment for Duchenne muscular dystrophy were analyzed. Results of an average follow-up period of 65 months (range, 49-79 mo) are described. METHODS: Nineteen male patients receiving steroids (0.9 mg/kg deflazacort) were compared with the natural history of Duchenne muscular dystrophy given in the literature. Additionally, 13 of these 19 patients were compared with an age-matched control group of 13 patients with Duchenne muscular dystrophy who were not receiving steroid treatment. They were not treated because of loss of independent walking before their first examination in our department or after informed consent with the parents. The same investigators followed all patients. RESULTS: Muscle strength, functional grade according to Vignos scale, and timed functional tests were significantly better in patients on steroids. The vital capacity was significantly improved in treated versus untreated boys; cardiologic examinations revealed no obvious difference. The main side effects of steroids in patients with Duchenne muscular dystrophy were obesity (2 of 13), cataracts (6 of 13), and short stature (II of 13). Rates of infectious diseases or of bone fractures resulting from osteoporosis were not increased. CONCLUSION: Long-term steroid treatment in Duchenne muscular dystrophy (average. 65 mo) proved beneficial m terms of muscle strength, function, and tolerable side effects, as compared with untreated patients with Duchenne muscular dystrophy.

Creatine therapy in myophosphorylase deficiency (McArdle disease): a placebo-controlled crossover trial.

OBJECTIVE: To determine whether treatment with creatine can improve exercise intolerance in myophosphorylase deficiency (McArdle disease). DESIGN: Double-blind, placebo-controlled crossover study with oral creatine monohydrate supplementation. PATIENTS: Nine patients with biochemically and genetically proven McArdle disease were treated. INTERVENTION: Five days of daily high-dose creatine intake (150 mg/kg body weight) were followed by daily low-dose creatine intake (60 mg/kg). Each treatment phase with creatine or placebo lasted 5 weeks. MAIN OUTCOME MEASURES: The effect of treatment was estimated at the end of each treatment phase by recording clinical scores, ergometer exercise test results, phosphorus 31 nuclear magnetic resonance spectroscopy, and surface electromyography. RESULTS: Of 9 patients, 5 reported improvement of muscle complaints with creatine. Force-time integrals (P =.03) and depletion of phosphocreatine (P =.04) increased significantly during ischemic exercise with creatine. Phosphocreatine depletion also increased significantly during aerobic exercise (P =.006). The decrease of median frequency in surface electromyograms during contraction was significantly larger (P =.03) with creatine. CONCLUSION: This is the first controlled study indicating that creatine supplementation improves skeletal muscle function in McArdle disease.

[Anesthetic complications. The incidence of severe anesthetic complications in patients and families with progressive muscular dystrophy of the Duchenne and Becker types]. / Narkosezwischenfälle. Inzidenz schwerer Narkosezwischenfälle bei Patienten und in Familien mit progressiven Muskeldystrophien vom Typ Duchenne und Becker.

UNLABELLED: During the last 30 years a great number of case reports presented severe anaesthetic complications with sudden cardiac arrest in patients with muscular dystrophies, mostly unsuspected at the time of the event. As succinylcholine was involved in the majority of the intractable incidents with lethal outcome the Food and Drug Administration (FDA) of the United States recommended a warning of the administration of succinylcholine in young children and adolescents in 1992 and an extensive international discussion on the routine use of succinylcholine in paediatric anaesthesia. Epidemiological studies on this issue are rare. We projected an inquiry about the incidence rate and type of severe anaesthetic complications in an utmost large number of patients and families with Duchenne (DMD) and Becker type (BMD) muscular dystrophy. METHODS: With the approval of the ethic committee of the university Witten/Herdecke and informed consent of the participants we investigated all patients and families who were diagnosed, controlled and treated for DMD or BMD as inpatients or outpatients in a "Muscle Centre" since 1983. The questionnaire asked for the number of patients per family, classification of the disease DMD or BMD, number and date of anaesthetics in the patients and eventual complications, anaesthetics and eventual complications in the parents, siblings and relatives and the occurrence of malignant hyperthermia (MH) in the family or relatives. Statistical assessments were done by Fisher's exact test for stratified 2 x 2 tables and Zelen's test for homogeneity of odds ratios. RESULTS: 200 out of 224 questionnaires could be evaluated. The diagnosis was confirmed by molecular genetic and immunohistochemical investigations. In 147 families it turned out to be DMD, in 53 families BMD. The 212 male and 9 female patients in the 200 families were given 444 anaesthetics. Sudden cardiac arrest occurred in 6 patients, all successfully resuscitated. Nine less severe incidents consisted of fever, symptoms of rhabdomyolysis (CK-elevation, dark coloured urine, hyperkalemia) and masseter spasm. The statistical assessment revealed that the occurrence of an event was highly dependent whether the diagnosis of muscular dystrophy was established or not (p < 0.0001, Fisher's exact test). All six cardiac arrests occurred in the 45 families with undiagnosed disease and no event happened in the 134 families with already known DMD/BMD. There was evidence that the number of anaesthetics without prior establishment of the diagnosis decreased after 1992 (p = 0.004, Fisher's exact test). CONCLUSIONS: Our results demonstrate that severe incidents and cardiac arrests occurred only in young children with undiagnosed DMD or BMD who received inhalational agents and succinylcholine. A cardiac arrest in 6 out of 200 families was found much more frequently than in the normal paediatric population (about 1:1000 to 1:3000). The decrease of events after 1992 (warning of the FDA) and disappearance of sudden cardiac arrests in our group of patients might be due to the world wide discussion on routine use of succinylcholine in children or the much earlier establishment of the diagnosis in our population. An early diagnosis of DMD and BMD and the avoidance of the triggering agents succinylcholine and volatile anaesthetics can reduce the risk of severe anaesthetic complications.

A common mutation (epsilon1267delG) in congenital myasthenic patients of Gypsy ethnic origin.

OBJECTIVE: Mutation analysis of the acetylcholine receptor (AChR) epsilon subunit gene in patients with sporadic or autosomal recessive congenital myasthenic syndromes (CMS). BACKGROUND: The nicotinic AChR of skeletal muscle is a neurotransmitter-gated ion channel that mediates synaptic transmission at the vertebrate neuromuscular junction. Mutations in its gene may cause congenital myasthenic syndromes. A recently described mutation in exon 12 of the AChR epsilon subunit (epsilon1267delG) disrupts the cytoplasmic loop and the fourth transmembrane region (M4) of the AChR epsilon subunit. METHODS: Forty-three CMS patients from 35 nonrelated families were clinically classified as sporadic cases of CMS (group III according to European Neuromuscular Centre consensus) and were analyzed for epsilon1267delG by PCR amplification and sequence analysis. RESULTS: The authors report the complete genomic sequence and organization of the gene coding for the epsilon subunit of the human AChR (accession number AF105999). Homozygous epsilon1267delG was identified in 13 CMS patients from 11 independent families. All epsilon1267delG families were of Gypsy or southeastern European origin. Genotype analysis indicated that they derive from a common ancestor (founder) causing CMS in the southeastern European Gypsy population. Phenotype analysis revealed a uniform pattern of clinical features including bilateral ptosis and mild to moderate fatigable weakness of ocular, facial, bulbar, and limb muscles. CONCLUSIONS: The mutation epsilon1267delG might be frequent in European congenital myasthenic syndrome patients of Gypsy ethnic origin. In general, patients (epsilon1267delG) were characterized by the onset of symptoms in early infancy, the presence of ophthalmoparesis, positive response to anticholinesterase treatment, and the benign natural course of the disease.

Phenotypic variability in rippling muscle disease.

OBJECTIVE: To characterize the phenotype of hereditary rippling muscle disease (RMD) and to report the results of genetic linkage studies. BACKGROUND: RMD is a rare autosomal-dominant inherited muscle disorder. Individuals complain of muscle stiffness, exercise-induced muscle pain, and cramp-like sensations. The characteristic feature of RMD is increased mechanical muscle irritability, which is electrically silent in electromyographic examinations. METHODS: Forty-six individuals from two unrelated German kindreds with RMD were examined. Linkage analysis to the RMD locus on chromosome 1q41-q43 was performed. RESULTS: In kindred A, 15 individuals from four generations, and in kindred B, four individuals from three generations had clinical features of RMD. The most consistent clinical findings were percussion-induced rapid muscle contractions (PIRCs) and muscle mounding, which were present in all 19 affected individuals. Only 12 individuals exhibited muscle rippling, indicating that rippling is not always present in RMD. Twelve of 19 individuals had muscle-related complaints, primarily exertional cramps and stiffness. The mean age at the onset of complaints was 22 years (range, 5 to 54 years). Seven of 19 individuals showed only mechanical-induced muscle irritability but did not have muscular symptoms. Genetic analysis excluded linkage to the RMD locus on chromosome 1q4 in both kindreds. CONCLUSIONS: The phenotype of RMD is variable but generalized PIRCs are the most obvious and reliable clinical feature of RMD. Diagnostic criteria of RMD should include generalized PIRCs in addition to muscle mounding, rippling, and creatine kinase elevation.

Short stature in Duchenne muscular dystrophy: a study of 34 patients.

In Duchenne muscular dystrophy (DMD), short stature is a feature of unknown cause. This cross-sectional study of 34 male patients (mean age 8.0 y, age range 1.2-13.7 y) was conducted to examine the relationship between auxological parameters, markers of growth and the extent of muscular weakness. Weight and length at birth (SDS +/- SD; 0.0 +/- 1.2; 0.2 +/- 1.5) and target height SDS (-0.2 +/- 0.7) were normal. Height (HT) SDS (-1.0 +/- 1.1) was lower than the normal population (p < 0.001) and did not correlate with age. Body mass index SDS (-0.1 +/- 1.6) was normal. Tests of insulin-like growth factor-I SDS (-0.6 +/- 1.2) and insulin-like growth factor binding protein-3 SDS (0.1 +/- 1.3) ruled out a severe derangement in the GH-IGF-axis. The carboxy-terminal propeptide of type I procollagen (PICP) SDS (0.6 +/- 1.5) was normal, but bone-specific alkaline phosphatase (BAP) SDS (-1.7 +/- 0.8) was low (p <0.001). HT SDS did not correlate with BAP SDS. The Vignos scale, a grading of muscular function (score: 0 = unaffected; 11 = confined to bed) (median (range): 3 (0-9)) correlated strongly with age (r = 0.77, p < 0.0001), but did not correlate with HT SDS, PICP SDS or BAP SDS. In conclusion, DMD patients are significantly shorter than the normal population, though the HT SDS does not change with age. Growth hormone deficiency does not seem to be the cause of short stature in DMD. Significantly low BAP levels are probably the result of the reduced muscle mass, which leads to a lower biomechanical load on the bone and thus a reduction in bone turnover. The short stature observed in our study is unlikely to be the result of muscular weakness.

[Regional distribution of predisposition to maligant hyperthermia in Germany: tate in 1997]. / Die regionale Verbreitung der Veranlagung zur Malignen Hyperthermie in Deutschland: Stand 1997.

Malignant hyperthermia (MH) is a rare autosomally dominantly hereditary and potentially life-threatening disease. The prevalence of the genetic MH predisposition is estimated as 1:10,000 to 1:20,000. In Germany no data on the regional distribution are available. Therefore, the purpose of this investigation is to summarise and present the epidemiological data of all German MH laboratories. Nine German hospitals offer the specific in vitro contracture test to diagnose the MH predisposition. All German MH laboratories carry out the examination in accordance with the standardised protocol of the European Malignant Hyperthermia Group. The laboratories were asked to provide the number of all patients investigated, excluding those suffering from other neuromuscular diseases, separated according to diagnostic groups and their places of residence, the number of the identified MH-families as well as the number of the clinically suspected and investigated MH cases with their places of residence. Eight MH laboratories provided the requested data. Until September 1997 a total of 2620 patients were investigated. In 865 patients (34%) MH suspicion was confirmed (diagnosis: MHS). 1494 patients (56%) were released by investigation from MH-suspicion (diagnosis: MHN). In 261 patients (10%) the MH-predisposition remained unsolved (diagnosis: MHE). 580 MH families were identified. Among 2620 patients 757 were clinically suspected MH cases. 35% of these suspected MH cases were classified as MHS, 10% as MHE and 55% as MHN. The documentation of the patients places of residence classified as MHS and MHE into a map of Germany demonstrates an exhaustive distribution with an increased regional prevalence in the areas of the MH laboratories. This concentration in the area of the MH laboratories becomes even more evident, when the places of residence of the MH suspected cases are demonstrated. In conclusion, the distribution of the MH predisposition is uniform and exhaustive in Germany. The presented regional concentration of clinically suspected MH cases among the MH laboratories is mainly interpreted as an expression of effective regional education and information. Considering the overall incidence of the MH predisposition as described above only 15-20% of the MH patients have so far been identified. The MH laboratories have already released about 10,000 patients from the suspicion of MH predisposition. A preliminary prevalence of at least 1:60,000 to 1:80,000 in Germany can be estimated according to the presented data.