1/46. Autosomal dominant distal myopathy not linked to the known distal myopathy loci.The distal myopathies are clinically, pathologically and genetically heterogenous. Thus far, seven types of distal myopathy have been linked to four chromosome loci. We recently examined four affected members from three generations of an autosomal dominant distal myopathy kindred. A muscle biopsy was performed on the index case. Muscle histopathology showed non-specific myopathic findings including increased variation in fiber size and increased internalized nuclei. No abnormal inclusions or vacuoles were present. Microsatellite markers for the four distal myopathy loci on chromosomes 2, 9 and 14 were studied on affected and several unaffected family members. Affected patients developed distal weakness in anterior foreleg muscles followed by progressive distal upper and proximal lower extremity involvement. Chromosome 2, 9 and 14 regional markers were informative and demonstrated recombinations with affected individuals in the pedigree. The resulting LOD scores obtained from the multipoint analyses gave no evidence of positive linkage to any of the regions and positively excluded (lod score less than -2) all, or virtually all, of the candidate regions examined. This autosomal dominant distal myopathy family does not show evidence of linkage to any of the known distal myopathy loci, suggesting the existence of at least one more distal myopathy locus. Furthermore, the clinical and pathological features appear distinct from other previously described but genetically-undetermined autosomal dominant distal myopathies.- - - - - - - - - - ranking = 1keywords = myopathies (Clic here for more details about this article) |
2/46. Myopathy with trabecular muscle fibers.A systematic review of muscle biopsies over a 15 year period in a large neurological hospital revealed 21 cases (7% of the total of non-inflammatory myopathies) with a distinctive pattern of myopathology and a limb-girdle clinical phenotype. The muscle pathology was dominated by a large prevalence (20-90%) of trabecular or lobulated fibers in which maldistribution of intermyofibrillar mitochondria produced a lobulated pattern of oxidative enzyme activity on transverse sections. The clinical picture was characterized by adult onset, slowly progressive muscle weakness affecting mainly proximal limb musculature, although mild distal weakness was also present in 60% of the cases. The trabecular pattern of oxidative enzyme reaction reflects maldistribution of the intermyofibrillar mitochondria; this may be caused by malfunction of a putative anchoring mechanism. While trabecular fibers can occur as a nonspecific alteration of muscle fibers in many diverse myopathies, the high prevalence of trabecular fibers as the dominant pathology in trabecular fiber myopathy makes it a distinctive (though not necessarily etiologically homogeneous) clinico-pathological entity.- - - - - - - - - - ranking = 1keywords = myopathies (Clic here for more details about this article) |
3/46. Mitochondrial 3243 A-->G mutation (MELAS mutation) associated with painful muscle stiffness.The mitochondrial mutation A-->G at nucleotide position 3243 is associated with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and other mitochondrial encephalomyopathies. We found this mutation in a 61-year-old patient who developed at the age of 54 a myopathy with painful muscle stiffness as the predominant symptom. Additionally hypacusis, a mild hemisensory syndrome and impaired glucose tolerance were present. Muscle histopathology showed few ragged red fibers. The mutation was detected heteroplasmatically in dna from muscle and blood. So far painful muscle stiffness has not been a known phenotype of the 3243 mutation.- - - - - - - - - - ranking = 0.5keywords = myopathies (Clic here for more details about this article) |
4/46. Cervical cord tethering mimicking focal muscular atrophy.spinal cord tethering rarely occurs in the cervical region. In adults, it usually results from previous operations. However, congenital origin is always diagnosed and treated early in the infant period. We report a 12-year-old boy with cervical spinal dysraphism which was erroneously diagnosed as focal muscular atrophy, a benign form of motor neuron disease. The patient was brought to our hospital because of rapid deterioration of symptoms. Careful evaluation disclosed a hairy dimple at the nuchal area, which led to the correct diagnosis. X-ray of the cervical spine showed spina bifida from C(4) to C(6) levels and fusion of the laminae of C(4) and C(5). spine MRI studies disclosed that the cervical cord was tethered caudally and dorsally, and the ventral nerve roots were markedly stretched, especially over the left side. Surgical intervention was undertaken and the patient's muscle power improved after untethering. The purpose of this report is to acquaint the reader with a surgically treatable condition that may appear to be benign focal amyotrophy. skin lesion at the nuchal area should be carefully looked for.- - - - - - - - - - ranking = 0.0051444576100479keywords = congenita (Clic here for more details about this article) |
5/46. Fluctuating clinical myotonia and weakness from Thomsen's disease occurring only during pregnancies.Advances in molecular genetics are allowing better phenotype to genotype correlation of the non-dystrophic myotonic disorders. We report a 32-year-old woman, who first noted myotonia that was associated with weakness during her first pregnancy. The work-up disclosed that she had Thomsen's disease which is not known to be associated with weakness. In addition, her myotonia was of the fluctuating type and occurred (symptomatically) only during two pregnancies. We discuss the evaluation of myotonia in the pregnant woman which led to the diagnosis of Thomsen's disease and we conclude that in exceptional cases, fluctuating myotonia and weakness occurs in autosomal dominant chloride channel myotonia (Thomsen's disease).- - - - - - - - - - ranking = 2.7808505314306keywords = myotonia (Clic here for more details about this article) |
6/46. A novel 7.4 kb mitochondrial deletion in a patient with congenital progressive external ophthalmoplegia, muscle weakness and mental retardation.We present a patient with external ophthalmoplegia, bilateral ptosis, progressive muscle weakness with "ragged-red fibres" and mental retardation. Mitochondrial dna analysis by Southern blot revealed heteroplasmy in muscle for a 7.4 kb deletion. In white blood cells, the deletion was only detectable by PCR. There was no evidence for duplications, nor for multiple deletions in the proband or siblings. PCR analysis did not reveal the presence of a mitochondrial dna defect in the parents and siblings. Thus, there is no experimental support for a maternally inherited mitochondrial dna deletion. We consider this a sporadic case with a de novo deletion. Diabetes and complaints of fatigue, also seen in this family, are probably coincidental. Mental retardation has been reported occasionally in patients with mitochondrial deletions, but is not common.- - - - - - - - - - ranking = 0.020577830440192keywords = congenita (Clic here for more details about this article) |
7/46. Minicore myopathy in children: a clinical and histopathological study of 19 cases.Minicore myopathy is a congenital myopathy characterized by multifocal areas of degeneration in muscle fibres. genetic heterogeneity expected on the basis of clinical variability awaits further resolution. We reviewed 19 cases in order to further delineate the phenotype. Marked hypotonia was the predominant presenting feature, with evidence of antenatal onset in 30% of cases. Weakness was most pronounced axially and proximally, often more severely affecting the shoulder girdle. Mild facial involvement was frequent. Varying degrees of scoliosis were obvious in all patients older than 10 years. In addition, two patients who were also the most severely affected had complete external ophthalmoplegia. One patient showed marked distal involvement. Respiratory failure developed in half of all patients after 10 years of age and correlated strongly with the degree of scoliosis. Cardiac involvement occurred mainly secondary to respiratory impairment. The course appeared static in most cases. Loss of independent walking was observed only in one case at the age of 10 years. On ultrasound scan, differential involvement within the quadriceps was documented in several patients. Variability in fibre size, type 1 predominance and atrophy with occasional type 2 hypertrophy were prominent but nonspecific histological changes. Apart from typical minicores, a marked increase in internal nuclei was the most prominent histological feature. With the exception of one family in which two generations were affected, inheritance appeared autosomal-recessive or sporadic in all cases.- - - - - - - - - - ranking = 0.0051444576100479keywords = congenita (Clic here for more details about this article) |
8/46. Respiratory failure due to muscle weakness in inflammatory myopathies: maintenance therapy with home mechanical ventilation.polymyositis and dermatomyositis are idiopathic inflammatory myopathies. Respiratory complications are a common feature, but ventilatory insufficiency is rare in these patients. We describe here three patients diagnosed with inflammatory myopathy (polymyositis) with respiratory failure due to muscle weakness who did not respond to immunosuppressive therapy. Mechanical ventilation at home with nasal or tracheal intermittent positive pressure resulted in improved chronic hypoventilation. This treatment improves the quality of life of patients with inflammatory myopathies and can be lifesaving in some cases.- - - - - - - - - - ranking = 3keywords = myopathies (Clic here for more details about this article) |
9/46. Facial and skeletal malformations, mental retardation, aganglionosis, and neurogenic muscle weakness: a variant of Niikawa-Kuroki syndrome or a new syndrome?We report a 10-year-old boy with multiple congenital anomalies/mental retardation syndrome, who also presented with aganglionosis and neurogenic muscle weakness. Some phenotypic manifestations of our patient overlap with those observed in the Niikawa-Kuroki syndrome; however, the hypothesis of a new distinct entity, with simultaneous involvement of the central and peripheral nervous system, is considered.- - - - - - - - - - ranking = 0.0051444576100479keywords = congenita (Clic here for more details about this article) |
10/46. A deceptive case of amyloid myopathy: clinical and magnetic resonance imaging features.Amyloid myopathy is a well-described, increasingly recognized clinical entity. Similar to inflammatory myopathies, amyloid myopathy presents with proximal muscle weakness and can be associated with elevated levels of muscle enzymes. We report the case of a 58-year-old woman who, at presentation to her physician with proximal muscle weakness and congestive heart failure, was antinuclear antibody positive and had muscle biopsy findings "consistent with inflammatory myopathy." She was referred to Johns Hopkins University Medical Center with the diagnosis of polymyositis. Further investigation revealed a monoclonal gammopathy, a unique patterning of subcutaneous fat reticulation and hypodense bone marrow changes on magnetic resonance imaging (MRI), and an endocardial biopsy sample that was positive for light chain amyloid deposition. paraffin sections of the muscle biopsy sample from the time of her original presentation were obtained, and congo red staining showed diffuse amyloid deposition throughout the sample, but no inflammation. This case not only illustrates that proximal muscle weakness due to primary amyloid myopathy (as found in light chain amyloidosis and transthyretin amyloidosis) can mimic that of polymyositis, but also shows that unique findings on MRI can alert the clinician to the diagnosis of amyloidosis prior to muscle biopsy.- - - - - - - - - - ranking = 0.5keywords = myopathies (Clic here for more details about this article) |
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