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At least 19 recordsLinked to original sources
PubMed1992

Could it be myotonic dystrophy? Myotonic dystrophy presenting with atrial flutter.

Myotonic dystrophy is a well recognised and well defined multisystem disorder which is inherited in an autosomal dominant fashion through a locus on chromosome 19. The disease itself is characterised by rigidity and degeneration of skeletal muscle, cataract formation, gonadal atrophy, frontal baldness and mental retardation. Like many inherited disorders there is a variable expression and so diverse clinical presentations can occur.

Adult↗
PubMed1990

Mechanism of muscle wasting in myotonic dystrophy.

Myotonic dystrophy is associated with progressive muscular atrophy. In order to determine the mechanism of muscle wasting in this condition, we measured fractional mixed skeletal muscle protein synthesis in the postabsorptive state in 8 patients with myotonic dystrophy, and compared the results with those of 10 normal subjects. Fractional muscle protein synthesis was determined by measuring the increment of 13C leucine in mixed skeletal muscle protein obtained by needle biopsy from the quadriceps muscle during a primed-continuous infusion of L-(1-13C) leucine. We used plasma 13C alpha-ketoisocaproate (representing intracellular leucine labeling) as the precursor pool for the calculation of fractional muscle protein synthesis and leucine kinetics. Fractional muscle protein synthesis was depressed in the patients with myotonic dystrophy (28% decrease, p less than 0.02). Leucine flux, leucine oxidation, and the nonoxidative portion of leucine flux were not different between the patients with myotonic dystrophy and the normal control subjects. Muscle atrophy in myotonic dystrophy reflects a selective decrease in muscle protein synthesis without any similar decrease in nonmuscle protein synthesis. This decrease may result from an impaired end-organ response to anabolic hormones or substrates.

Adult↗
PubMed1992

Gastric volvulus complicating myotonic dystrophy.

Myotonic dystrophy is an autosomal inherited disorder of both striated and smooth muscle, and is considered to be a rare cause of gastrointestinal dilatation and abnormal peristalsis. We report on a patient with myotonic dystrophy complicated by gastric volvulus. A 57-year-old female with myotonic dystrophy suddenly developed abdominal pain, nausea and vomiting. X-ray examinations revealed gastric dilatation and pyloroantral obstruction, consistent with acute gastric volvulus. The patient underwent successful emergency gastrectomy. Gastric volvulus is often an unrecognized surgical emergency, but its clinical and radiographic features are so characteristic that accurate diagnosis is possible if the condition is kept in mind. Thus, the clinician should consider the possibility of gastric volvulus when evaluating gastrointestinal complaints in patients with myotonic dystrophy.

Acute Disease↗
PubMed1992

Dermal lymphatics in myotonic dystrophy.

Myotonic dystrophy is an hereditary disorder of several organ systems. Skeletal muscle is a principal target organ, but abnormalities also occur in the peripheral microcirculation. Because morphological and functional changes in the dermal blood microcirculation may affect interstitial fluid drainage of the skin, we examined dermal lymphatic morphology in adult patients with myotonic dystrophy. Skin biopsies were taken from the big toe from patients with myotonic dystrophy (age 18-50 years) and subjected to light and electron microscopy; five healthy subjects served as controls. The salient findings in myotonic dystrophy were ultrastructural changes of the lymphatic endothelial cells and the fibrillar elements that surround the lymphatic wall. These abnormal lymphatic findings are interpreted in light of changes in the blood microvasculature and loose connective tissue in this disorder.

Adolescent↗
PubMed1990

[Respiratory pathophysiology during sleep in patients with myotonic dystrophy].

Myotonic dystrophy is a genetic disorder inherited as an autosomal dominant trait. It is known to be associated with endocrine dysfunction, polar cataracts, cardiac abnormalities and other conditions. Respiratory distress constituents the principal problem in myotonic dystrophy. The author investigated postural change of respiratory function in 12 patients with myotonic dystrophy (MYD), and 7 patients with limb-girdle dystrophy (LG) and overnight polysomnography was performed on 10 patients with MYD and 5 patients with LG. The respiratory function in seated posture showed no significant difference between LG and MYD, but in patients with MYD, the vital capacity and the expiratory reserve volume in a supine posture was reduced in comparison to that during seated posture. However, the respiratory function in patients with LG was not significantly different in seated and supine postures. Also, in patients with MYD, there was a significant decrease in arterial PO2 from the seated posture to the supine posture, without a significant change in the arterial PCO2. However, in patients with LG, there was no significant change in arterial blood gas analysis parameters. It was speculated that these findings concerning respiratory function and blood gas analysis in patients with MYD were caused by the involvement of the diaphragm. In the supine posture, the diaphragm shifted to the cranial position because of the abdominal contents rising into thorax, therefore the lung volume was reduced and the ventilation-perfusion ratio deteriorated. The changes of respiratory function parameters and PaO2 were partly responsible for the hypoxemia observed during sleep in patients with MYD. Overnight polysomnography showed that 9 of the 10 patients with MYD and 1 of the 5 patients with LG presented apneas during sleep, particularly during REM, stage 1 and stage 2. Almost all apneas were central type, with a low percentage of obstructive apneas and the apnea index was 19.0/h (mean) in MYD, 6.5/h in one case of LG. These result strongly suggest that sleep apnea is of central origin, but the distinction between a central and an obstructive etiology is difficult in neuromuscular disease and particularly when a disorder of central ventilatory responsiveness is suspected. The respiratory function of MYD and LG in seated and supine postures was studied and overnight polysomnography performed. It was emphasized that it was important for the respiratory care of neuromuscular disease to consider the influence of postural changes in the respiratory function. The present series of studies revealed central sleep apnea in the patients with myotonic dystrophy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Expansion of an unstable DNA region and phenotypic variation in myotonic dystrophy.

Myotonic dystrophy is the commonest adult form of muscular dystrophy, with an estimated incidence of 1 per 7,500, although this is likely to be an underestimate because of the difficulty of detecting minimally affected individuals. It is a multisystem autosomal dominant disorder of unknown biochemical basis. No case of new mutation has been proven. We have isolated a human genomic clone that detects novel restriction fragments specific to individuals with myotonic dystrophy. A two-allele EcoRI polymorphism is seen in normal individuals, but in most affected individuals one of the normal alleles is replaced by a larger fragment, which varies in length both between unrelated affected individuals and within families. The unstable nature of this region may explain the characteristic variation in severity and age at onset of the disease. A second polymorphism at this locus is in almost complete linkage disequilibrium with myotonic dystrophy, strongly supporting our earlier results which indicated that most cases are descended from one original mutation.

Blotting, Southern↗
PubMed1992

Relative disease severity in siblings with myotonic dystrophy.

Myotonic dystrophy is an autosomal dominant disorder in which an early-onset form is characteristically inherited from the mother. We studied 17 affected sibling pairs from 15 families in which two or more affected children were born to mothers with myotonic dystrophy. Later-born affected children suffered more severe disease than their first-born siblings in 13 of 17 sibling pairs. Later-born affected siblings displayed significantly more neonatal feeding difficulties, later age when first sitting alone, later age when first walking alone, and a higher incidence of scoliosis. The overall difference in disease severity between affected siblings increased as the age difference between them increased, suggesting that increasing maternal age is a factor in the relative disease severity of affected children. These findings may have relevance for genetic counseling.

Adult↗
PubMed1990

[Genetic analysis of Spanish families with myotonic dystrophy].

Myotonic dystrophy (MD) is the most common form of muscular dystrophy in adult life, with a clinical prevalence of 5.5/100,000, being the gene prevalence of 13.5. The disease is autosomal dominant with variable expressivity, existing a congenital form with a severe prognosis. Recent genetic studies revealed that the DM gene is localized in the chromosome's 19 proximal long arm and with recombinant DNA techniques, several polymorphic markers have been isolated near the gene, the closet being Apo-CII, LDR 152 and p 4.1. We have studied clinically, electrophysiologically and by genetic analysis 6 families with 32 individuals. We have diagnosed the disease in 16 individuals and after the molecular analysis, the DM gene was totally excluded in 6 clinically healthy individuals. In our preliminary study, the use of Msp I/p 4.1, Bgl II/LDR 152 y Ban I, Bgl I, Taq I/Apo-CII c-DNA and genomic was found the most informative combination. These molecular analysis seem to be very useful as a complement to the diagnosis of myotonic dystrophy.

Adolescent↗
PubMed1978

Cardiac conduction abnormalities and Stokes-Adams attacks in myotonic dystrophy.

Myotonic dystrophy is a well known cause of cardiomyopathy. While various cardiac conduction abnormalities have been described in patients with myotonic dystrophy, so far only sporadic cases of Stokes-Adams attacks have been reported. Of 27 patients with this disease various conduction disturbances were detected in 17 (63%), 5 of whom presented with Stokes-Adams attacks and were found to have intracardiac conduction defects. The prognosis in four of the five patients was greatly improved with permanent pacemaker implantation.

Adams-Stokes Syndrome↗
PubMed1975

Neonatal respiratory failure due to myotonic dystrophy.

Myotonic dystrophy should be included in the differential diagnosis of neonatal respiratory failure accompanied by hypotonia. The effect of this disorder in an infant who died from it 49 hours after birth is described, and the importance of examining the mother of a possible case is emphasized.

Humans↗
PubMed1992

Case report: selective occipital lobe hydrocephalus and agenesis of the left lobe of the liver in congenital myotonic dystrophy.

Myotonic dystrophy (Steinert's disease) is an uncommon familial autosomal dominant disease, characterized by progressive muscular atrophy and myotonia. Mental retardation, frontal baldness, cortical lenticular opacities and testicular atrophy are other prominent features of a disease that involves predominantly striated muscle. There is little information regarding this disease in the radiological literature. The present report introduces two additional findings involving the skull and the liver.

Adolescent↗
PubMed1976

Basal metabolic rate in patients with hydrocephalus. On the cause of lowered basal metabolic rate in myotonic dystrophy.

Myotonic dystrophy seems to have a hypometabolism of non-thyroid origin. The hypometabolism could hypothetically be caused by : 1) reduction in muscle mass, 2) hydrocephalus ex vacuo, an integral part of the disorder, or 3) the basic disease process itself. Possibility 2) was explored by determining basal metabolic rate (BMR) in 41 patients with dilatation. A BMR of less than -10 per cent was found in eight cases. The ventricles were categorized in three groups according to width. No decrease in mean BMR was found in cases with a marked ventricular enlargement. Thus, ventricular dilatation per se does not seem to lead to hypometabolism.

Adult↗
PubMed1991

[Myotonic dystrophy].

Myotonic dystrophy (MD) is illustrated by a characteristic case report. MD is a dominantly inherited multi-organic disease with complete penetrance, but with highly variable expression illustrated by the near relatives of this patient. The disease usually follows a slow, progressive course. The cardinal symptoms are myotonia, muscle atrophia, cataract and a characteristic facial appearance. Cardial arrhythmias, endocrine and mental changes also occur. The liability to arrhythmias and the weakened respiratory muscles of the patients which lead to ventilatory insufficiency makes anesthesia and surgical operation risky. The diagnosis, which is made by electromyography, is easy in typical cases, but suspicion that the disease is present is seldom raised in very mild cases if there is no recognition of familial cases. Meticulous examination of near relatives of severe cases is therefore essential to take advantage of the possibilities of prenatal diagnosis recently made possible through developments in DNA technology.

Adult↗
PubMed1992

[Aggravation of hypoxemia in supine position in myotonic dystrophy].

Myotonic dystrophy (MyD) involves a variety of systems. Respiratory disorders are common, namely elevation of diaphragm, alveolar hypoventilation, aspiration pneumonia and sleep apnea. We evaluated respiratory involvement. The subjects were 11 patients with MyD. Also 6 patients with limb girdle muscular dystrophy (LG) were examined to be compared with MyD. Both groups had the similar activities of daily living. All of them never complained of dyspnea. Arterial blood gas studies were performed in supine position and standing position. A new evidence was found that hypoxemia was aggravated and alveolar-arterial oxygen pressure difference was increased in supine position in MyD. Next, pulmonary function tests were done in supine position and sitting position. Functional residual capacity (FRC) were more reduced in supine position in MyD compared with LG. The value to subtract closing capacity from FRC was negative in supine position in MyD, showing closing phenomenon. We propose the mechanism of the aggravation of hypoxemia may be the following. The reduction of FRC caused by respiratory muscle involvement brings out the closing phenomenon. Abnormal uneven distribution of ventilation-perfusion ratio happens and then hypoxemia is worsened in supine position in MyD.

Adult↗
PubMed1992

Detection of an unstable fragment of DNA specific to individuals with myotonic dystrophy.

Myotonic dystrophy (DM) is the most common form of adult muscular dystrophy, with a prevalence of 2-14 per 100,000 individuals. The disease is characterized by progressive muscle weakness and sustained muscle contraction, often with a wide range of accompanying symptoms. The age at onset and severity of the disease show extreme variation, both within and between families. Despite its clinical variability, this dominant condition segregates as a single locus at chromosome 19q13.3 in every population studied. It is flanked by the tightly linked genetic markers ERCC1 proximally and D19S51 distally; these define the DM critical region. We report the isolation of an expressed sequence from this region which detects a DNA fragment that is larger in affected individuals than in normal siblings or unaffected controls. The size of this fragment varies between affected siblings, and increases in size through generations in parallel with increasing severity of the disease. We postulate that this unstable DNA sequence is the molecular feature that underlies DM.

Chromosomes, Human, Pair 19↗
PubMed1992

Beta-adrenergic system in myotonic dystrophy.

Myotonic dystrophy (DM) is considered an inherited membrane disorder, but the basic defect is unknown. We studied plasma catecholamines as well as lymphocyte and muscle beta-adrenergic receptor densities and functioning in 19 DM patients and 15 control subjects. Plasma adrenaline and noradrenaline concentrations were not significantly different between DM patients and controls. In isolated lymphocytes basal cAMP production was 157 +/- 26 pmol/mg protein/10 min in DM patients and 91 +/- 12 pmol/mg protein/10 min in controls (n.s.), whereas isoproterenol-stimulated cAMP production was significantly higher in DM patients (285 +/- 42 pmol/mg protein) compared with control subjects (168 +/- 21 pmol/mg protein, P less than 0.05). Lymphocyte beta-adrenoceptor densities were similar among DM patients (50 +/- 3 fmol/mg protein) and controls (47 +/- 5 fmol/mg protein). beta-Adrenoceptor densities were also similar in muscle biopsy specimens (12.9 +/- 1 in DM and 13.1 +/- fmol/mg protein in controls). The correlation between lymphocyte and skeletal muscle receptor densities was r = 0.35 in DM patients and r = 0.22 in controls. The results do not support the hypothesis of adrenergic dysfunction in DM despite its membrane involvement.

Adolescent↗
PubMed1992

[Molecular genetics diagnosis of Steinert's myotonic dystrophy].

Myotonic dystrophy (DM) is the most common neuromuscular disease with adult onset (incidence 1 in 8000). The biochemical basis of this autosomal dominantly inherited disease is still unknown. The most striking features are myotonia and progressive muscular wasting. There is high variability of disease severity in patients from different families, but also within the same family. For practical reasons three subtypes can be defined: The classical adult onset form of the disease, a mild form with late onset and/or very moderate symptoms, eg. cataracts only, and the most severe congenital form which is transmitted by affected females. Furthermore, the progression of DM in affected families may exhibit an increase in the severity of the disease in successive generations. This observation is called anticipation. Very recently the DM gene has been cloned and an unstable DNA sequence specific for the disease has been characterized. Detection of an enlarged DNA fragment due to the expansion of a trinucleotide (CTG) repeat within the DM gene can be used for direct DNA diagnosis in affected individuals and persons at risk. Furthermore, there is a strong correlation between the length of fragment expansion and the degree of disease severity in gene carriers. We report here our preliminary results of the investigation of over 70 patients and demonstrate the clinical usefulness of this new method by the findings in three families.

Adult↗