Dystrophy Type Research Articles

Coexisting Muscular Dystrophies and Epilepsy in Children

Muscular dystrophies are composed of a variety of genetic muscle disorders linked to different chromosomes and loci and associated with different gene mutations that lead to progressive muscle atrophy and weakness. Fukuyama congenital muscular dystrophy is frequently associated with partial and generalized epilepsy and congenital brain anomalies, including cobblestone complex and other neuronal migration defects. We report generalized convulsive epilepsy in a boy with normal brain magnetic resonance imaging and Duchenne muscular dystrophy with deletion of dystrophin gene, and we report absence epilepsy with normal brain magnetic resonance imaging in another boy with limb girdle muscular dystrophy with partial calpain deficiency. We, therefore, review coexisting muscular dystrophies and epilepsy in children. In addition to Fukuyama congenital muscular dystrophy, partial or generalized epilepsy has also been reported in the following types of muscular dystrophies, including Duchenne/Becker dystrophy, facioscapulohumeral dystrophy, congenital muscular dystrophy with partial and complete deficiency of laminin alpha2 (merosin) chain, and limb girdle muscular dystrophy with partial calpain deficiency.

Proteomic investigation of the molecular pathophysiology of dysferlinopathy

Mutations in dysferlin gene cause several types of muscular dystrophy in humans, including the limb-girdle muscular dystrophy type 2B and the distal muscular dystrophy of Miyoshi. The dysferlin gene product is a membrane-associated protein belonging to the ferlins family of proteins. The function of the dysferlin protein and the cause of deterioration and regression of muscle fibres in its absence, are incompletely known. A functional clue may be the presence of six hydrophilic domains, C2, that bind calcium and mediate the interaction of proteins with cellular membranes. Dysferlin seems to be involved in the membrane fusion or repair. Molecular diagnosis of dysferlinopathies is now possible and the types of gene alterations that have been characterized so far include missense mutations, deletions and insertions.

Sickness impact in people with muscular dystrophy: a longitudinal study over 10 years

To describe changes of function in terms of sickness impact over 10 years in adult patients with different types of muscular dystrophy. Patients with muscular dystrophy answered the Sickness Impact Profile and Self-report ADL questionnaires in 1991 and 2001. The study population was identified in a comprehensive prevalence study in the county of Orebro, Sweden. The study group comprised 44 people grouped according to whether they had myotonic dystrophy or muscular dystrophy with proximal or distal muscles affected. Comparison was made between assessments of sickness impact in terms of function at the two time points. Most obvious deterioration over time was in activities of daily living that require finger and arm strength. Ambulation was significantly decreased in myotonic dystrophy and proximal muscular dystrophy. Those walking without assistive devices decreased from 91% to 52%, and the number with a disability pension increased from 36 to 55%. There was a relatively small influence with regard to psychosocial dysfunction assessed by the Sickness Impact Profile. This longitudinal study shows the deteriorating functions reported by patients with muscular dystrophy. This knowledge could be used to formulate new interventions in order to offer appropriate support and treatment to this patient group.

When Science Is Not Enough: Fighting Genetic Disease in Brazil

The ability to identify genetic signs of diseases is advancing faster than the ability to treat those diseases. For Mayana Zatz, a professor of genetics at SA£o Paulo University in Brazil, this mismatch is a compelling call to conduct basic laboratory research into such diseases and to do what she can to improve the lives of those afflicted by them. In the case of Duchenne muscular dystrophy and other types of muscular dystrophy, Zatz has helped uncover the biomolecular bases of some of these diseases, counseled thousands of affected individuals and families about how to manage their condition, and established an association and clinic to help improve the lives of her country9s poorest victims of Duchenne muscular dystrophy. Zatz chronicles the research, ethical conundrums, and legal challenges that she confronts in her molecules-to-society attack on Duchenne muscular dystrophy and other neuromuscular disorders. All essays appearing in this series can be found online atwww.sciencemag.org/sciext/globalvoices/

Analysis of gene mutation in Chinese patients with Reis-Bücklers corneal dystrophy

To identify the mutation of the TGFBI gene in Chinese patients with Reis-Bücklers corneal dystrophy, and to study the relationship between the gene mutation and the clinical appearance. Ten patients and 2 unaffected family members from 2 unrelated families with corneal dystrophy were studied. Molecular genetic analysis was performed on DNA extracted from peripheral leucocytes, and exons 4 and 12 of the TGFBI gene were amplified by polymerase chain reaction for direct sequencing. Both pedigrees showed an autosomal dominant inheritance. The clinical appearance of the cornea consisted of fine granular, subepithelial opacities which spread and become confluent with time, and resembled geographic type of Reis-Bücklers corneal dystrophy. Direct sequencing of all affected members revealed a G-to-T transition at codon 124 (CGC to CTC), producing R124L mutation of TGFBI gene. R124L mutation of the TGFBI gene is found in two Chinese families with Reis-Bücklers corneal dystrophy. The phenotype of Reis-Bücklers corneal dystrophy in both families belongs to the geographic type. Molecular genetic approach may be useful for the proper diagnosis of this type of corneal dystrophy.

Histopathological Characterization of the Skeletal Myopathy in rasH2 Mice Carrying Human Prototype c-Ha-ras Gene

A skeletal myopathy is found in approximately 100% of rasH2 mice. To confirm detailed features of the rasH2 skeletal myopathy, the biceps femoris, diaphragm, triceps brachii, gastrocnemial (types I and II fiber-mixed muscles) and soleus muscle (type I fiber-dominant muscle) obtained from male rasH2 and non-transgenic littermates aged 10-13 and 34 weeks were examined. Variations in the muscle fiber size, early-scattered degeneration/necrosis and regeneration of muscle fibers were detected in 10-13-week-old rasH2 mice. The severity of the above muscular lesions was more prominent in older rasH2 mice. These lesions were noted in the type II myofiber dominant muscles (biceps femoris, triceps brachii and gastrocnemial). NADH-TR stain clearly demonstrated a disorganized intermyofibrillar network and necrotic change in muscle fibers. No specific morphological changes, like rod structure or tubular aggregation seen in some types of myopathy, were noted in Gomori trichrome and NADH-TR stains in the rasH2 mouse like in many types of muscular dystrophy. Electronmicroscopically, occasional muscle fiber degeneration/regeneration, invaded phagocytic cells, indistinct Z-band suggesting excessive contraction and dilatation of the sarcoplasmic reticulum were observed. In summary, the skeletal myopathy occurring in rasH2 mice is consistent with muscular dystrophy characterized morphologically by progressive degeneration and regeneration of myofibers. The myopathy is confined to the type II myofiber predominant muscles and is not associated with any pathognomonic lesions. These characteristics will provide us with a useful model for research in muscular dystrophy of diverse myofibers.

MUSCULAR DYSTROPHIES: A NOVEL PLAYER

![Figure][1] Muscular dystrophies are inherited disorders leading to progressive muscle destruction. Duchenne's disease and another type of muscular dystrophy result from genetic defects that affect the dystrophin-glycoprotein complex (DGC). The DGC is a network of proteins that contacts the

Improvement of the diagnostic procedure in proximal myotonic myopathy/myotonic dystrophy type 2.

Proximal myotonic myopathy/myotonic dystrophy type 2 (PROMM/DM 2) is caused by an expansion of the (TG)n(TCTG)n(CCTG)n repeat tract in intron 1 of the ZNF9 gene located on chromosome 3q21. Because these expansions show a marked mitotic instability, expanded alleles are often difficult to detect. In order to improve the diagnostic procedure, we applied a combination of pulsed-field gel electrophoresis and semi-quantitative Southern blot analysis with a novel hybridization probe. The combination of these methods led to unequivocal results in about 98% of cases with a clinical diagnosis of PROMM/DM 2. Furthermore, we report the genotype/phenotype correlation in a patient lacking a normal ZNF9 allele and a further proband with a "grey zone" allele.

New molecular research technologies in the study of muscle disease

To describe the current technologies and progress in DNA polymorphism association studies, mRNA expression profiling (microarrays), and proteomics with respect to muscle disease, and the increasing impact of public-access databases of genome-wide information. mRNA expression profiling is becoming the most mature of the highly parallel molecular technologies, with microarrays now able to query the large majority of all genes using 1 million oligonucleotide probes built on 1.2-cm2 glass substrates. Applications of microarrays to normal muscle physiology and muscle disease are discussed. Single nucleotide polymorphism association studies promise to determine the predisposition of individuals to acquired muscle disease, including sarcopenia and atrophy, although such studies are in their infancy. Proteomics technologies do not enjoy the sensitivity and specificity of hybridization, and must instead rely on mass spectrometers. Mass spectrometry technology is advancing rapidly, although the sensitivity and throughput is far behind that of mRNA expression profiling. As the gene mutations responsible for many types of muscular dystrophy and myopathy have been discovered, protein and gene testing has been integrated into the standard patient diagnostic workup. Future developments will include simpler and less expensive molecular diagnostics, advances in the understanding of downstream consequences of these defects, and the genetic predispositions underlying acquired muscle disease.

Classificação diagnóstica dos portadores de doenças degenerativas de retina, integrantes dos grupos Retina São Paulo e Retina Vale do Paraíba

OBJETIVO:Organizar um banco de dados regional de todos os indivíduos portadores de doenças degenerativas da retina, com o objetivo de classificar cada paciente de acordo com o tipo de distrofia e padrão de herança. MÉTODOS: Durante o encontro do Grupo Retina São Paulo no dia 5 de maio de 2001, duzentas e quarenta e três pessoas foram registradas, sendo que parte forneceu dados de antecedentes oculares, pessoais e familiares e árvore genealógica. Noventa e três pacientes foram questionados quanto a idade, origem, tipo de distrofia, história familiar e árvore genealógica, tipo de herança, outras anomalias sistêmicas e exames complementares. Foram classificados quanto ao diagnóstico e padrão de herança. RESULTADOS: Dos duzentos e quarenta e três pacientes registrados, as distrofias encontradas foram retinose pigmentária, doença de Stargardt, síndrome de Usher, amaurose congênita de Leber e coroideremia. Quanto à divisão por doença dos 93 pacientes argüidos, havia 62 pacientes com retinose pigmentária, 13 com doença de Stargardt, 13 com síndrome de Usher, três com amaurose congênita de Leber e dois com coroideremia. Dos pacientes com retinose pigmentária, o padrão de herança detectado foi autossômico dominante em quatro casos (7%), autossômico recessivo em vinte casos (32%), ligado ao cromossomo X recessivo em sete casos (11%), caso isolado em vinte e nove (47%) e padrão indeterminado em dois (3%). Para a doença de Stargardt três indivíduos (23%) seguiam o padrão de herança autossômico recessivo e dez (77%) eram casos isolados. Dos treze pacientes com síndrome de Usher, oito (61,5%) apresentavam herança autossômica recessiva, quatro (31%) eram casos isolados e um (7,5%) tinha o padrão de herança indeterminado. Os dois pacientes com coroideremia seguiam o padrão de herança ligado ao X recessivo. Para amaurose congênita de Leber, um paciente (33,5%) tinha padrão autossômico recessivo de herança e dois (66,5%) eram casos isolados. CONCLUSÃO: Destaca-se assim a importância desta classificação como a primeira referência nacional dos padrões de hereditariedade das distrofias retinianas do país. Este é o primeiro passo para se proceder em seguida a classificação genético-molecular baseada no seqüenciamento de cada gene responsável por cada um dos padrões de herança. A freqüência de cada tipo específico é semelhante à encontrada em outros trabalhos epidemiológicos de outros países.

Limb-Girdle Muscular Dystrophies

The phenotype in limb-girdle muscular dystrophy (LGMD) type 21 was defined by mutation analysis, protein studies, and respiratory and cardiac involvement studied in 16 patients from 14 families with fukutin-related protein (FKRP) gene mutations and LGMD, at the Institute of Human Genetics, University Newcastle upon Tyne, UK.

Imaging and pathology in pediatric neurological disorders.

Radiologic and pathologic findings correlate well in many pediatric neurologic disorders. However, there are some exceptions. Radiologic techniques are unable to visualize or identify pathologic changes in some diseases (e.g. status marmoratus and subdural fluid collection), whereas pathologic examination fails to clarify the histologic substrate of radiologic abnormalities in other conditions (e.g. Fukuyama-type congenital muscular dystrophy and neurofibromatosis type 1). Although studies to solve these issues have met with practical difficulties, important progress has recently been made on some disorders such as Fukuyama-type congenital muscular dystrophy and acute necrotizing encephalopathy.

Depressed myocardial fatty acid metabolism in patients with muscular dystrophy

Myocardial involvement is frequently associated with various types of muscular dystrophy and Thallium-201 scintigraphy can show regional myocardial perfusion abnormalities in patients with muscular dystrophy. Myocardial fatty acid metabolism can now be imaged using a radioiodinated branched fatty acid (123I-BMIPP). The present study evaluates myocardial fatty acid metabolism in muscular dystrophy. Twenty-eight patients underwent 123I-BMIPP(BMIPP) and Thallium dual single photon emission tomography. Regional uptake of both tracers was visually analyzed. We also assessed electrocardiography and echocardiography. The results showed that the BMIPP uptake compared to Thallium was smaller in 57% of all patients. BMIPP SPECT images revealed abnormalities in four of eight patients with a normal electrocardiogram. Abnormal BMIPP uptake with normal regional wall motion was evident in nine patients. The size of the region with defective BMIPP uptake was larger than that of asynergic areas detected by echocardiography in 11 patients. In conclusion, muscular dystrophy involves depressed myocardial fatty acid metabolism in larger extent of region than that in perfusion or mechanical abnormality.

Coagulation and fibrinolysis disorder in muscular dystrophy

To investigate whether there are any basic abnormalities of coagulation and fibrinolysis in muscular dystrophy, we measured serum levels of the MM isozyme of creatine kinase (CK-MM), fibrin and fibrinogen degradation products (FDP), plasma levels of fibrinogen, antithrombin (AT), and D-dimer in 36 patients with Duchenne muscular dystrophy (DMD), 11 with Becker muscular dystrophy (BMD), 5 with Fukuyama congenital muscular dystrophy (FCMD), 5 with myotonic dystrophy (MyD), and 5 with spinal muscular atrophy (SMA) type 2. FDP levels were elevated in the patients with DMD, BMD, and FCMD (1.0 to 84.9 μg/ml), but not in the patients with MyD and SMA type 2. In DMD, BMD, and FCMD, FDP levels significantly correlated with CK-MM, but not with age, fibrinogen, AT, D-dimer, and type of dystrophy (multiple regression analysis; r2 = 0.814, P < 0.0001). These findings suggested that enhanced coagulation and fibrinolysis are associated with muscle degeneration in patients with DMD, BMD, and FCMD. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 399–402, 2001

Gene therapy for muscular dystrophies: current status and future prospects.

Since the identification in 1987 of the gene for Duchenne muscular dystrophy (DMD), research on the molecular pathogenesis of muscular dystrophy has progressed extensively. In particular, discovery of the DMD gene product, dystrophin, led to the identification of dystrophin-associated proteins and, subsequently, the recognition of other types of muscular dystrophy caused by the defects in each of the sarcoglycan genes. On the other hand, effective therapy for DMD has not yet been established. Some of the viral vectors, such as adeno-associated virus vectors or lentiviral vector, have been proven to enable the long-term expression of the exogenous gene without overt host immune reactions. However, dystrophin cDNAs are too large (14kb) to be accommodated in these viral vectors. To solve this problem, we and other research groups succeeded in truncating full-length dystrophin cDNA to small dystrophin cDNA (4 to 5kb), the products of which protect dystrophin-deficient mdx muscle from contraction-induced membrane damage when introduced by viral vectors or as a transgene into mdx mice. The usefulness of these truncated dystrophin cDNAs should be confirmed using other animal models such as dystrophic dogs. To develop successful treatment of DMD, the authors believe that several different approaches should be used, such as cell transfer therapy, drug design to up-regulate utrophin, or a strategy to repair the mutation in vivo.

Coagulation and fibrinolysis disorder in muscular dystrophy

To investigate whether there are any basic abnormalities of coagulation and fibrinolysis in muscular dystrophy, we measured serum levels of the MM isozyme of creatine kinase (CK-MM), fibrin and fibrinogen degradation products (FDP), plasma levels of fibrinogen, antithrombin (AT), and D-dimer in 36 patients with Duchenne muscular dystrophy (DMD), 11 with Becker muscular dystrophy (BMD), 5 with Fukuyama congenital muscular dystrophy (FCMD), 5 with myotonic dystrophy (MyD), and 5 with spinal muscular atrophy (SMA) type 2. FDP levels were elevated in the patients with DMD, BMD, and FCMD (1.0 to 84.9 microg/ml), but not in the patients with MyD and SMA type 2. In DMD, BMD, and FCMD, FDP levels significantly correlated with CK-MM, but not with age, fibrinogen, AT, D-dimer, and type of dystrophy (multiple regression analysis; r(2) = 0.814, P < 0.0001). These findings suggested that enhanced coagulation and fibrinolysis are associated with muscle degeneration in patients with DMD, BMD, and FCMD.

A man, a syndrome, a gene: Clouston's hidrotic ectodermal dysplasia (HED).

This paper presents a biographical sketch of Dr. H. R. Clouston, whose eponym is attached to a type of hidrotic ectodermal dystrophy, and a brief account of the mapping of the gene and its identification as the connexin gene, GJB6.

Evaluation of the strength of elbow flexors in patients with neuromuscular diseases

In planning the optimum treatment for patients with neuromuscular diseases (NMD), it is essential to know as much as possible about their functional state. Assessment of the strength of certain muscles is the most direct measure of motor deficiency. In the development of normative data needed for patients with NMD, the use of torque measurements is required. Forty-nine patients (31 men and 18 women), from 18 to 54 years (mean age 33 - 8.9 years), were included in the study. Five groups of patients, each having one of five different NMDs, were formed. We tested unilaterally the biceps brachii muscle that normally generates the highest torque. For this purpose an electronic brace enabling isometric measurements of torque during elbow flexion was designed. The patients produced three maximum voluntary elbow flexions that lasted about 3 s and separated by a pause of about 3 s. Force development was rapid with continuous build-up and isometric. About 15 s later the patients produced the last maximum voluntary elbow flexion, keeping it as stable as possible for a period of 30 s. Patients with mitochondrial myopathy (MM), having the shortest mean halffatigue time (4.3 s), elicited the highest mean torque in both short maximum voluntary elbow flexions (1.34 Nm) as well as in the 30 s-long maximum voluntary elbow flexions. In contrast, patients with facioscapulohumeral muscular dystrophy (MD-FSH), having the longest mean half-fatigue time (15.4 s), elicited the lowest mean torque in both the short maximum voluntary (0.29 Nm) as well as in 30 s-long maximum voluntary elbow flexions. Patients with Becker muscular dystrophy (MD-B), having a mean half-fatigue time (11.1 s) slightly shorter than the patients with MD-FSH, elicited a higher mean torque in both the short (0.82 Nm) and the 30 s-long elbow flexions. Finally, patients with limb-girdle muscular dystrophy (MD-RM) and spinal muscular atrophy type 3 (SMA3), having a similar mean half-fatigue time (6.9 s for patients with MD-RM and 7.4 s for patients with SMA3), also elicited similar torque in both short (0.45 Nm for patients with MD-RM and 0.65 Nm for patients with SMA3) and 30 s-long elbow flexions. The results of the study show that the methodology developed to quantitatively measure the torque of elbow flexions in patients with NMD enables the characteristics and natural course of NMD to be more objectively documented. Accordingly, the optimum treatment for patients with NMD could be restored.

New therapies in muscular dystrophies.

Muscular dystrophies are a group of hereditary muscle disorders that often result in severe disability. Curative therapy is not yet available for muscular dystrophies (MD). In the near future, it is not expected that gene-replacement therapy will be available. Other strategies to decrease the rate of muscle necrosis and to increase strength in patients are necessary. Therefore the interest in symptomatic drug treatment has recently increased. A few trials have been performed on different types of muscular dystrophies, and some have generated positive results on muscle strength or muscle mass. We review the state of the art in therapy of MD and summarize the drugs that have been used and the evidence and results of such clinical trials.

Hints for a cure in a muscular dystrophy variant

The transition from the pre-molecular era into the molecular era of myology has increased the understanding of the molecular defects underlying muscle disease. For a large group of muscular dystrophies, the defects are related to disturbances in the linkage between the intracellular cytoskeleton network and the extracellular matrix network. For other types of muscular dystrophy, it is more difficult to see how a defective protein can cause muscle disease. A paper by Galbati et al. significantly adds new insight into a rare form of muscular dystrophy. The autosomal dominant limb girdle muscular dystrophy (LGMD-1C) in humans arises owing to mutations within the gene encoding caveolin-3. Caveolin-3 is a major structural component of caveolae in skeletal muscle. It has previously been shown that LGMD-1C mutations lead to formation of unstable aggregates of caveolin-3 that are retained intracellularly and are degraded rapidly.