Dystrophy Type Research Articles

Dystrophin-glycoprotein complex

Recent molecular and biochemical studies have disclosed the detailed molecular organization of the dystrophin-glycoprotein complex, which links the cytoskeleton to the extracellular matrix. Defects in several components of this complex cause different types of muscular dystrophy. This glycoprotein complex is also involved in clustering and anchoring acetylcholine receptors at the postsynaptic membrane.

Duchenne muscular dystrophy and spinal muscular atrophy type I segregating in the same family.

We report on a family with two severe neuromuscular diseases: Duchenne muscular dystrophy (DMD) and acute infantile spinal muscular atrophy (SMA I). One boy has DMD, and his brother died of SMA I at 11 months of age. Both boys had received the same DMD allele from their mother. Analysis of dystrophin by immunohistochemistry and Western blot showed complete lack of dystrophin in both brothers. The mother had a partial deficiency of dystrophin. The boy with SMA I had increased levels of creatine kinase in serum, compatible with DMD, but the muscle biopsy and post-mortem examination of the spinal cord showed the typical changes of SMA I. There were no cytogenetic abnormalities explaining the occurrence of both DMD and SMA I in this family. Molecular genetic prenatal diagnosis of DMD and SMA I, using analysis of RFLPs and dinucleotide repeats, has been performed in one foetus in the family. The results showed that the foetus had a high risk of developing SMA I. An abortion was planned but the pregnancy was terminated by miscarriage.

Immunologic Study of the Hyaline—vascular Type of Castleman's Disease: A Case Study

We report a case of Castleman's disease in a 48-year-old male who complained of a rapidly enlarging mass on the neck. Thrombocytopenia and the facio-scapulo-humeral type of progressive muscular dystrophy were also present. The mass was extirpated, and histopathological examinations showed the hyaline-vascular type of Castleman's disease. Following resection, thrombocytopenia was ameliorated. Immunological study with flow cytometric analysis was made to clarify the nature of his mass. With reference to recent literature we suggest that the hyaline-vascular type of Castleman's disease may be an atypical hyperplasia of the lymphoid tissue.

The heart in muscular dystrophy: An electrocardiographic and ultrasound study of 20 patients

Twenty patients with different types of muscular dystrophy (MD) were included in a cross-sectional study by means of electrocardiography and ultrasound cardiography. A manifest cardiomyopathy was detected in 8 patients; a latent cardiomyopathy was found in 4. A hypertrophic cardiomyopathy was especially frequent in facioscapulohumeral MD, a congestive cardiomyopathy in Becker-Kiener MD. The ECG showed a reduction in the QT interval and frequent block formers in the X-chromosomal inherited forms and the trunc-girdle form. Bradycardia and a prolonged QT interval were frequent in myotonic dystrophy and facioscapulohumeral MD. Signs of cardiac infarction in the ECG were most frequent in the trunc-girdle forms. A high cardiac output per minute in conjunction with increased left ventricular volume was frequent in Becker-Kiener and Landouzy MD. A left ventricular dysfunction with reduced ejection was characteristic of myotonic dystrophy and trunc-girdle MD. A mitral valve prolapse was more frequent with increasing severity of the muscle disease and was particularly frequent in myotonic dystrophic and Landouzy MD. The cardiac output per minute and the stroke volume were significantly lower (P less than or equal to 0.03) where a mitral valve prolapse was present.

A Japanese Family With Two Types of Muscular Dystrophy: DNA Analysis and the Dystrophin Test

A unique Japanese family with both Fukuyama type congenital muscular dystrophy (FCMD) and Duchenne muscular dystrophy (DMD) is described. Four boys, all from the sixth generation of the same family, were afflicted with severe neuromuscular diseases beginning in early life, three of them presenting the typical phenotype of FCMD and one, that of DMD. Although DNA analysis by Southern blotting with complementary DNAs representing the whole of the dystrophin coding sequence detected neither gross deletions nor duplications, immunohistochemistry and Western blotting of the biopsied skeletal muscle with an antidystrophin monoclonal antibody (dystrophin test) showed that the approximately 400-kd dystrophin was expressed normally at the sarcoplasmic membrane of the FCMD phenotype patient but was completely absent in the DMD phenotype patient. From these results, it was presumed that two different childhood muscular dystrophies, FCMD and DMD, coexisted in this family. This unique case illustrates the efficacy of the dystrophin test in the differential diagnosis of the two diseases even when conventional means of diagnosis do not give definite answers and DNA analysis of the dystrophin gene is not informative.

Immunohistochemical Study of Fiber Types in Human Extraocular Muscles

Fiber types in human extraocular muscle (h-EOM) were examined immunohistochemically with antibodies against slow tonic (anti-ALD) and slow twitch (anti-SOL) myosins. Four types of muscle fiber in h-EOM were distinguishable according to their reactivities with these antibodies. Groups 1 and 2 fibers reacted with both antibodies, group 1 fibers showing stronger reactivity than group 2 fibers with anti-ALD. Group 3 fibers reacted only with anti-SOL. Group 4 fibers did not react with either antibody. The latter were the most common, and were the main fibers in both the peripheral (outer orbital) and central zones of h-EOM. The next most common were group 1 fibers, which were located mainly in the peripheral layer. Group 2 fibers were less common, but were the second most common type in the central layer. Group 3 fibers were only minor constituents. Multiple innervations were observed in some fibers of groups 1 and 2, and group 1 fibers were suggested to be slow tonic myofibers in h-EOM. These specific immunohistochemical and physiological features of h-EOM seem to be the basis of the low morbidity seen in the usual types of muscular dystrophy.

New type of X‐linked progressive muscular dystrophy involving shoulder girdle and back

A new type of X-linked muscular dystrophy is described in a family in which 7 men had boyhood onset of progressive dystrophy involving muscles of the shoulder and back but not the calves or face. The scapula-back muscles are affected, but the calf muscles are normal. All patients are still able to walk. The oldest patient is now 37 years old. The muscular dystrophy has been specified by electromyography, pathologic tissue microscopic examination, electron microscopic study, and elevated CK. This type of muscular dystrophy has not been reported previously.

Dystrophin immunostaining in muscles from patients with different types of muscular dystrophy: a Brazilian study

The localization of the protein dystrophin was studied using the immunofluorescence method, in muscle biopsies from 74 patients affected by different types of muscular dystrophy and 4 normal controls. In 15 patients with limb-girdle muscular dystrophy (LGMD) the pattern was indistinguishable from normal. Among 42 Duchenne patients (DMD), 3 were totally negative and 39 showed a variable proportion (4–30%) of partially labelled fibers. With one exception 17 Becker dystrophy patients (BMD), showed a positive sarcolemmal reaction. A diffuse reaction inside the fibers, which was not observed in normal controls, was seen in the majority of DMD and also in some of the BMD patients. Based on these observations it is suggested that in DMD, a small quantity of protein is still present or there is a cross-reaction with other proteins which share some homology with dystrophin. The present results suggest that it is possible to make a differential diagnosis between DMD and BMD through dystrophin immunohistochemistry. However, to distinguish between patients with BMD and LGMD phenotypes, or DMD and outliers, complementary immunoblot studies and quantitative determination of dystrophin are necessary.

Secretion and Clinical Significance of Atrial Natriuretic Peptide in Patients With Muscular Dystrophy

The plasma concentration of atrial natriuretic peptide was measured in patients with muscular dystrophies to study its relationship with congestive heart failure. In patients with Duchenne muscular dystrophy, the plasma atrial natriuretic peptide concentration was 35.5 +/- 3.3 pg/mL (mean +/- SE), which was higher than that in age-matched normal subjects (9.8 +/- 0.6 pg/mL). It increased with progression of disability and showed significant correlations with the cardiothoracic ratio and the ratio of the preejection period to the left ventricular ejection time. In patients with other types of muscular dystrophy, the plasma atrial natriuretic peptide concentration showed no significant change. Immunohistochemical examination demonstrated many atrial natriuretic peptide-positive cells in atrial muscle of an autopsied patient, indicating preservation of the peptide until the end stage. These findings suggest that measurement of the plasma atrial natriuretic peptide concentration is useful for evaluating heart failure in patients with Duchenne muscular dystrophy.

Intracellular free calcium concentration in lymphocytes of patients with muscular dystrophies

Intracellular free calcium concentration [( Ca2+]i) of human peripheral blood lymphocytes was determined by fluorescence spectroscopic measurements with quin2 in patients with different types of muscular dystrophy and in controls. The [Ca2+]i level in lymphocytes showed a significant increase in adult type (facioscapulohumeral and limb-girdle) muscular dystrophies, while it showed a decrease in Duchenne dystrophy as compared to the values of age- and sex-matched controls. The data obtained suggest an alteration in the effectiveness of the calcium pump in lymphocytes and may represent a sign of generalized membrane damage in these hereditary muscle diseases.

Muscular dystrophy-like disease in a thoroughbred foal

A 1-month-old male thoroughbred foal, which had difficulty in walking, was killed and examined by histological, histochemical and ultrastructural methods. The muscles of the trunk and upper hind limbs were chiefly affected, and changes in the affected muscles resembled those in muscular dystrophy in man. The type of muscular dystrophy present in this foal and the significance of this disease in thoroughbred horses are discussed. The dystrophy in this foal resembled the limb-girdle type or myotonic dystrophy of muscular dystrophy in man.

Lipid peroxidation and superoxide dismutase activity in muscle and erythrocytes in adult muscular dystrophies and neurogenic atrophies.

Lipid peroxidation (LP) and superoxide dismutase (SOD) activity were determined in erythrocytes and skeletal muscle obtained from patients with limb-girdle and facioscapulohumeral muscular dystrophies, neurogenic atrophies and from age-matched control subjects. Neither lipid peroxidation nor SOD activity in erythrocytes of patients differed from control values. SOD activity and LP in muscle specimens were also normal in types of neurogenic atrophy. Lipid peroxidation in the muscle from patients with adult types of muscular dystrophy had a tendency to be increased. The values were widely scattered, the highest being obtained in the older patients with long duration of disease.

Dystrophin and nebulin in the muscular dystrophies

Skeletal muscle from patients with 5 different forms of muscular dystrophy and from 6 fetuses at high risk (95%) for Duchenne muscular dystrophy (DMD) were probed with specific antibodies for the presence of dystrophin and nebulin. Dystrophin was absent in all 5 patients with DMD and 4 of 6 fetuses at high risk for DMD and present in trace amounts in the remaining two. Dystrophin was also undetectable in one borderline DMD/Becker muscular dystrophy (BMD) case and reduced in 2 of 4 cases of BMD. In contrast, dystrophin was present in all 16 biopsies from 4 other types of muscular dystrophy (congenital, limb girdle, Emery-Dreifuss and facioscapulohumeral). Nebulin profiles varied with the type, severity and duration of the dystrophic process. Nebulin was present in 5 of 6 DMD fetal samples but vastly reduced or absent in all samples of clinically manifest DMD.

A comparative study of thallium-201 single-photon emission computed tomography and electrocardiography in duchenne and other types of muscular dystrophy

Single-photon emission computed tomography (SPECT) using thallium-201 was compared with 12-lead electrocardiography (ECG) in patients with Duchenne (29), facioscapulohumeral (7), limb-girdle (6) and myotonic (5) dystrophies, by dividing the left ventricular (LV) wall into 5 segments. SPECT showed thallium defects (37 patients, mostly in the posteroapical wall), malrotation (23), apical aneurysm (5) and dilatation (7). ECG showed abnormal QRS (36 patients), particularly as a posterolateral pattern (13). Both methods of assessment were normal in only 7 patients. The Duchenne type frequently showed both a thallium defect (particularly in the posteroapical wall) and an abnormal QRS (predominantly in the posterolateral wall); the 3 other types showed abnormalities over the 5 LV wall segments in both tests. The percent of agreement between the 2 tests was 64, 66, 70, 72 and 72 for the lateral, apical, anteroseptal, posterior and inferior walls, respectively. The 2 tests were discordant in 31 % of the LV wall, with SPECT (+) but ECG (−) in 21% (mostly in the apicoinferior wall) and SPECT (−) but ECG (+) in 10% (mostly in the lateral wall). Some patients showed large SPECT hypoperfusion despite minimal electrocardiographic changes. ECG thus appeared to underestimate LV fibrosis and to reflect posteroapical rather than posterolateral dystrophy in its posterolateral QRS pattern. In this disease, extensive SPECT hypoperfusion was also shown, irrespective of clinical subtype and skeletal involvement.

Practical problems in the respiratory care of patients with muscular dystrophy.

THE muscular dystrophies comprise several groups of inherited disorders with a wide variation between the groups in the distribution and severity of muscle involvement.1 The respiratory muscles, in common with other skeletal muscles, are affected in all types of muscular dystrophy, so that patients have an increased risk of respiratory complications and premature death.2 Respiratory insufficiency often remains covert because impaired skeletal-muscle function prevents patients from exceeding their limited ventilatory capacity; however, it can easily be detected with routine pulmonary-function tests. The case for regular pulmonary assessment in neuromuscular disease has recently been cogently argued in the Journal.3 The . . .

Additional biochemical criteria in the differential diagnosis of myositis.

Thirty-six biopsy specimens of human biceps and vastus lateralis muscles were examined by histometric analysis and determination of enzyme activities (phosphorylase, triosephosphate dehydrogenase, 3-hydroxacyl-CoA-dehydrogenase, lactate dehydrogenase, hexose isomerase, citrate synthetase, 6-phosphogluconate dehydrogenase). The series included 13 specimens from patients suffering from a benign form of muscular dystrophy (limb girdle and Becker type of muscular dystrophy) and 12 specimens from patients with an acute (n = 5) or chronic (n = 7) form of myositis. Muscle fibres were atrophic in myositis and hypertrophic (with an increased variation of fibre diameters) in muscular dystrophies, as has been shown previously. When myositis samples were compared with either normal or dystrophic muscles, a highly significant lowering of glycolytic enzyme activity was found in chronic myositis, while the activity of 6-phosphogluconate dehydrogenase was elevated to highly significant levels. Measurements of the latter enzyme's activity might be of additional value in differentiating chronic forms of myositis from benign muscular dystrophies.

Reis-Bücklers corneal dystrophy

In the literature two types of anterior corneal dystrophy are referred to as Reis-Bücklers' dystrophy. These are the one originally described by Bücklers in 1949 and known by us as the geographical form, and a honeycomb form. On the basis of electron-microscopic findings the geographical form is considered by some authors today to be a superficial variant of the granular dystrophy (Groenouw I), while the honeycomb form is looked upon as the "true" Reis-Bücklers' dystrophy. However, there is no clinical resemblance between the honeycomb type and the dystrophy described by Bücklers. Clinically it is easy to distinguish the geographical and the honeycomb type, and this is important for the prognosis of a corneal graft. The present authors do not agree that the term granular dystrophy should include the dystrophy described by Bücklers. There is a lack of clarity concerning this type of dystrophy, and clinically it bears no resemblance to granular dystrophy. In the authors' opinion it would be preferable to speak of the geographical and the honeycomb form of Reis-Bücklers' dystrophy.

Muscular dystrophy in Saskatchewan Hutterites

A slowly progressive form of muscular dystrophy was studied in a Dariusleut Hutterite kindred from a colony in west-central Saskatchewan. The disorder combines some characteristics of the dominantly inherited facio-scapulo-humeral and the recessively inherited limb-girdle types of muscular dystrophy. Intellect, vision, hearing, and sensations were normally preserved. Nerve conduction was also intact. The disorder reported herein resembles a type of muscular dystrophy we previously described in the Manitoba Schmiedeleut Hutterites [Shokeir and Kobrinsky, 1976]. This condition, which affects both sexes, appears to be genetic in origin and recessively inherited.

The effects of inspiratory resistive training on respiratory muscle function in patients with muscular dystrophy

The effects of inspiratory resistive training on respiratory muscle function was evaluated in 11 patients with Duchenne, limb-girdle, and facio-scapulo-humeral (FSH) type muscular dystrophy. Muscle training consisted of breathing against an inspiratory resistance for two 15-minute sessions each day while at home. Following 6 weeks of training, there were significant increases in the maximum resistance that could be tolerated for at least 5 minutes (P < 0.01) and also in the maximum duration that ventilations equal to 30%, 50%, 70%, and 90% of the maximum voluntary ventilation could be sustained (P < 0.05). In six patients who trained for an additional 6-week period, respiratory muscle endurance increased even further. The degree of improvement in respiratory muscle endurance was positively correlated with baseline vital capacity (r = 0.84, P < 0.05) and maximal inspiratory pressure (r = 0.76, P < 0.05). Spirometry, functional residual capacity, and maximal inspiratory and expiratory pressures were not affected by training. We conclude that inspiratory resistive training improves respiratory muscle endurance in muscular dystrophy patients. Improvement in respiratory muscle function may serve to delay the onset of respiratory complications in patients with muscular dystrophy.

A Fukuyama type of congenital muscular dystrophy associated with atypical gyrate atrophy of the choroid and retina: A case report

A three-year-ten-month old boy with the Fukuyama type of congenital muscular dystrophy (FCMD), early onset of muscular hypotonia, severe mental retardation, a slow progressive course and a characteristic fundus appearance similar to that of gyrate atrophy is described. Hyperornithinaemia and iminoglycinuria were not noted. To our knowledge, this is the first reported case of FCMD associated with atypical gyrate atrophy of the choroid and retina.