Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dysmaturation (neuro)myopathy without specific histochemical or cytoarchitectural characteristics accounts for many cases of hypotonia in infancy. We obtained a maturation profile for type I and type II fibers from birth to 6 years of age, from which a classification of fiber dysmaturation based on fiber-type hypotrophy and coefficient of fiber variation is presented. We analyzed the morphometric, ultrastructural, and single fiber teasing findings in the sural nerve of ten infants with hypotonia and dysmaturation myopathy based on the above classification. Data on endoneurial area, myelinated fiber density, proportion of large (greater than 6 micron) myelinated fibers, unmyelinated fiber density, regression analyses of myelin area:axon area, and mean myelin thickness were developed. Abnormalities in large myelinated fiber density (3 cases), disturbances in myelination index (5), and single fiber teasing abnormalities in internode length (1) were found. Ultrastructural abnormalities were observed and classified as group 0 changes similar to the five control nerves; group 1, in which rare fibers showed degeneration or basement membrane duplication; and group 2, which was characterized by multiple abnormalities including degenerate nuclei, amyelinate fibers, degeneration/regeneration, excessive basal lamina reduplication, and hypomyelination. This study provides evidence that minimal neuropathic abnormalities are present in the sural nerve of infants carrying a diagnosis of dysmaturation neuromyopathy.
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PMID:Dysmaturation neuromyopathy: correlation with minimal neuropathy in sural nerve biopsies. 276 90

Congenital bronchomalacia is a disease typically associated with infants between 1 and 12 months of age; cases in children less than 1 month of age are rare. Bronchomalacia is commonly associated with tracheomalacia and rarely warrants operative intervention. Three cases of bronchomalacia are presented, including two unusual cases of bronchomalacia associated with neuromuscular disorder, one complicated by hypotonia. These patients required ventilatory support in the form of continuous positive airway pressure to prevent lobar collapse. Following tracheobronchial and neuromuscular maturation, these infants were able to weaned from respiratory assistance without further sequelae. Bronchomalacia is discussed, the literature reviewed, and the standard therapies presented. The results indicate a possible relationship between neuromuscular disorders and respiratory collapse.
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PMID:Bronchomalacia in the neonate. 390 58

A family composed of parents and four children is reported. Two brothers presented from early infancy with hypotonia and non-progressive weakness. Muscle biopsy in both revealed numerous typical nemaline rods. The father, suffering from backache, had a slow MNCV of both common peroneal nerves. His muscle revealed variation in fiber size, splitting, type 1 atrophy and numerous pleomorphic mitochondria with crystalline inclusions. The mother's muscle showed type 2 atrophy, foci of myofibrillar degeneration, and lipofuscin bodies. In a 12-year-old daughter and a 5-year-old son the muscle revealed an excess of small, bizarre mitochondria and lipid droplets. The coexistence of nemaline myopathy and a mitochondrial neuromuscular disorder in one family has never been reported in the literature. It might be a coincidence of two rare muscle disorders in one family, or it might be the polymorphic expression of a single etiological factor causing a defect in protein synthesis.
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PMID:Nemaline myopathy and a mitochondrial neuromuscular disorder in one family. 626

A male infant, born from consanguineous parents, suffered from birth with a progressive neuromuscular disorder characterized by psychomotor delay, hypotonia, muscle weakness and wasting, deep-tendon areflexia and spastic posture. High levels of lactic acid in blood and cerebrospinal fluid suggested a mitochondrial respiratory chain defect. Muscle biopsy revealed ragged-red and cytochrome c oxidase-negative fibres, lipid accumulation and dystrophic changes. Multiple defects of respiratory complexes were detected in muscle homogenate, but cultured fibroblasts, myoblasts and myotubes were normal. Southern blot analysis showed markedly reduced levels of mitochondrial DNA (mtDNA) in muscle, while lymphocytes, fibroblasts and muscle precursor cells were normal. Neither depletion of mtDNA nor abnormalities of the respiratory complexes were observed in innervated muscle fibres cultured for as long as 4 months. No mutations were observed in two candidate nuclear genes, mtTFA and mtSSB, retro-transcribed, amplified and sequenced from the proband's mRNA. Sequence analysis of the mtDNA D-loop and of the origin of replication of the mtDNA light strand failed to identify potentially pathogenic mutations of these replicative elements in the proband's muscle mtDNA. Our findings indicate that mtDNA depletion is due to a nuclear encoded gene and suggest that the abnormality underlying defective mtDNA propagation must occur after muscle differentiation in vivo.
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PMID:Early-onset encephalomyopathy associated with tissue-specific mitochondrial DNA depletion: a morphological, biochemical and molecular-genetic study. 855 15

Severe degenerative features of the nervous system of a hitherto unknown kind, associated with a neuromuscular disorder with histopathological features of congenital muscular dystrophy, are reported in two female siblings. The clinical profile was characterized by generalized hypotonia followed by spastic tetraplegia, contractures, polyneuropathy, lack of cognitive development and progressive microcephaly. There as no involvement of the eyes. Neuropathological examination of the brain of one sibling, who died at the age of 30 months, revealed subtotal loss of neurons in the cerebral and cerebellar cortex and in the ventral pons, and secondary loss of myelin in the cerebral and cerebellar subcortical white matter. Sural nerve biopsy in the other sibling, who had a similar neurological affection, showed a lack of large myelinated fibers.
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PMID:Congenital muscular dystrophy and severe central nervous system atrophy in two siblings. 861 88

myotonic dystrophy, also called the Curschmann-Steinert syndrome, is an autosomal dominant inherited neuromuscular disorder characterized by progressive muscular dystrophy, muscle weakness and myotonia, which can affect both mother and child. Complications may arise during pregnancy, delivery, including anaesthetic problems, and in the neonatal period. During pregnancy hydramnion can be a first sign of the disease leading to premature labor and also muscle weakness and myotonia can aggravate complicating the course of delivery. The affected neonate may display severe hypotonia, facial diplegia and respiratory distress. The clinical diagnosis can be confirmed by direct DNA analysis in serum and in chorionvillus biopsy material. In this case report two sisters with myotonic dystrophy are described, their pregnancies, deliveries and the outcome of their affected babies.
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PMID:Myotonic dystrophy in pregnancy: a report of two cases within one family. 922 95

Merosin-deficient congenital muscular dystrophy is an autosomal recessive neuromuscular disorder caused by partial or total absence of laminin-2 (merosin) in the skeletal muscle. Affected children have severe weakness, hypotonia at birth, high creatine kinase (CK) levels (more than 10 times normal) and are not able to walk or stand unsupported. Linkage and mutation analysis demonstrated that the gene encoding for the laminin-alpha2 chain, mapped on chromosome 6q22-23, is invariably responsible for this form of congenital muscular dystrophy. We investigated the pattern of inheritance of the haplotypes associated with the mutated allele in 29 informative merosin-deficient families, using tightly linked informative polymorphic microsatellite markers. This allowed us to identify heterozygous individuals from normal homozygotes, who are clinically, pathologically and biochemically indistinguishable. By linkage analysis, we found a statistically significant increase in the number of heterozygous individuals carrying either the paternal or the maternal haplotypes associated with the mutated allele. This could suggest a selection in favour of the alleles carrying mutations at the laminin alpha2-chain locus.
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PMID:Is there selection in favour of heterozygotes in families with merosin-deficient congenital muscular dystrophy? 1054 97

Neuromuscular disorders are common causes of weakness and hypotonia in the infantile period and in childhood. Accurate diagnosis of specific neuromuscular disorders depends first on identification of which aspect of the peripheral neuromuscular system is affected--the motor neuron in the spinal cord, the nerve root or peripheral nerve, the neuromuscular junction, or the muscle--and then on the determination of the etiology and specific clinical entity. This review provides an overview of the major neuromuscular disorders of childhood with attention to recent advances and emerging areas of research.
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PMID:Neuromuscular disorders of childhood. 1059 Sep 6

We determined prospectively the diagnostic value of quantitative ultrasonography in detecting neuromuscular disorders in children. Ultrasonographic scans of four muscles were made in 36 children with symptoms or signs suggestive of neuromuscular disease, such as muscle weakness and hypotonia. The muscle thickness, ratio of muscle thickness to subcutaneous fat thickness, and echo intensity were determined in each muscle. The echo intensity was measured using computer-assisted gray-scale analysis. Thirteen of the 36 patients had a neuromuscular disorder (6 a myopathy and 7 a neuropathy). Differentiation between neuromuscular diseases and nonneuromuscular diseases could be made on the basis of echo intensities with a sensitivity of 92%, a specificity of 90%, a positive predictive value of 86%, and a negative predictive value of 95%. We conclude that computer-assisted quantitative analysis of muscle echo intensity is a reliable method to discriminate between neuromuscular and nonneuromuscular diseases in children.
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PMID:Quantitative skeletal muscle ultrasonography in children with suspected neuromuscular disease. 1276 81

OBJECTIVE: To describe 6 patients with less than 3 years of age that were diagnosed with Prader-Willi syndrome (PWS) due to hypotonia, poor sucking, slight facial anomalies and minor abnormalities of hands and feet. PWS is a neurobehavioural disorder characterized by two distinct phases; in the first, the neonate presents variable degree of hypotonia, feeding problems with none or poor sucking; hypogonadism, characteristic facial features with almond shaped eyes, narrow bifrontal diameter and down-turned corners of the mouth. Neuropsichymotor development is delayed. Hypotonia is non progressive and tends to improve between 8 and 11 months of age. The second phase then starts and is characterized by increasing hyperphagia and obesity, among other features. Unfortunately, most PWS patients are diagnosed only after obesity is installed. METHODS: Methylation, microsatellites analysis and karyotypic studies by traditional and in situ hybridization techniques were done. RESULTS: A deletion of chromosome segment 15q11q13 was disclosed in 4 and maternal disomy in two patients. CONCLUSION: The diagnosis of PWS is generally established after the onset of obesity. So, we suggest that the genetic analysis must be carried out in children with severe hypotonia of unknown cause, poor sucking and some facial features of PWS (small hands and feet, hypogonadism, hypopigmentation, almond eyes and narrow bifrontal diameter). This can allow the early diagnosis and avoid invasive exams necessary for neuromuscular disorder diagnosis like muscle biopsy and electroneuromiography, wich frequently are associated with inconclusives results.
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PMID:[Hypotonic infants and the Prader-Willi Syndrome] 1464 78


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