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)

Muscle phosphofructokinase (PFK) deficiency in man is responsible for at least two forms of myopathy; one is characterized by painful contractures of muscles and typically occurs in adults, whereas the other is often disabling and typically occurs in childhood, with psychomotor and growth retardation. In this investigation, a young myopathic patient with severe mental retardation and aplasia of the cerebellar vermis presented with muscular hypotrophy of the limbs, generalized hypotonia, convergent strabismus and marked pain during passive movement. Biopsy of quadriceps femoris muscle showed variation in the fiber size with sarcoplasmic areas positive for periodic acid-Schiff stain. Histochemical qualitative reaction for PFK showed no staining of muscle fibers; ultrastructural studies showed abnormal accumulation of glycogen granules in both intermyofibrillar and subsarcolemmal areas. While some enzyme activities in the muscular crude extract were significantly lower than in controls, direct assay of PFK revealed no activity, thus demonstrating that the child's myopathy was due to the lack of PFK activity.
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PMID:Muscle phosphofructokinase deficiency in a myopathic child with severe mental retardation and aplasia of cerebellar vermis. 139 61

A 3-month-old girl was admitted to the hospital because of hypotonia and frequent vomiting. She had severe metabolic acidosis and her liver function was abnormal. Hepatomegaly and rapidly progressive liver failure developed, and she died at 4 months of age. Two half-siblings from a different mother had died in infancy of an undiagnosed myopathy. The liver was fatty and hepatocytes were filled with large and small lipid droplets. Other tissues were morphologically normal. The respiratory chain enzymes containing subunits encoded by mitochondrial DNA were markedly decreased in liver, partially decreased in muscle, but normal in other tissues. Southern blot analysis showed 90% depletion of mitochondrial DNA in liver, 53% depletion in muscle, and normal amounts in other tissues. This is the second case of fatal infantile liver failure associated with mitochondrial DNA depletion. This pathogenetic mechanism should be considered in infants with multiple respiratory chain defects and variable tissue expression.
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PMID:Fatal infantile liver failure associated with mitochondrial DNA depletion. 144 52

To investigate the diagnostic validity of electromyography in the hypotonic infant, 79 children aged 0 to 12 months, seen over a 20-year period, were studied retrospectively. The diagnoses using clinical, muscle biopsy, and laboratory characteristics were: 25 central hypotonia, 20 spinal muscular atrophy, 20 myopathy, four myotonic dystrophy, four benign congenital hypotonia, two congenital muscular dystrophy, two myasthenia gravis, one infantile inflammatory myopathy, and one arthrogryposis multiplex congenita. Using strict criteria, electromyography accurately predicted the final diagnosis in 65% of infants with spinal muscular atrophy and was consistent with the diagnosis in another 25%. In contrast, electromyography accurately predicted the final diagnosis in only 10% of infants with myopathy and was normal in 88% of infants with central hypotonia. In infants with spinal muscular atrophy, there was no difference in the predictive value of electromyography when performed in the newborn compared to older infants. Normal distal nerve conduction velocities in infants with spinal muscular atrophy may predict prognosis, since these infants had a longer survival. Electromyography thus has a high predictive value for infantile spinal muscular atrophy but not for myopathy.
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PMID:Predictive value of electromyography in diagnosis and prognosis of the hypotonic infant. 146 46

The muscle biopsy results from 14 children with macrocephaly and hypotonia/weakness were correlated with clinical findings compatible with any of the autosomal dominant macrocephaly syndromes. Thirteen of the 14 had evidence of lipid storage myopathy, either generalised or focal. All 13 had examinations consistent with either benign familial macrocephaly, Ruvalcaba-Myhre-Smith syndrome, or Bannayan-Zonana syndrome. These results suggest that all three of these disorders may represent phenotypic variability at a single genetic locus.
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PMID:Correlation of skeletal muscle biopsy with phenotype in the familial macrocephaly syndromes. 155 44

A girl presents immediately post partum with postures and movements typical for severe muscular hypotonia (floppy infant). Her sucking and swallowing abilities are reduced. There is marked drooling. Broad alveolar ridges give the impression of a high-arched palate. Floppy infant-screening (muscle enzymes, EMG, NCV) was within normal ranges apart from a slight elevation of aldolase. Muscle biopsy performed at the age of two years revealed the diagnosis of nemaline myopathy. An onset of the disease with severe muscular hypotonia during neonatal period usually is linked with rapidly progressing, mostly lethal outcome. Our patient--in contrast--seems to suffer from a mild form.
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PMID:[Nemaline myopathy: an unusual course]. 164 15

The case of a 2-day-old male full-term newborn with myotubular (centronuclear) myopathy is reported. He presented with generalized hypotonia and muscle weakness, swallowing disturbance, and respiratory distress at birth. He had a typical myopathic face, high-arched palate, funnel chest, and mild bilateral ptosis. Deep tendon reflexes were absent. Serum creatine kinase was normal. The histologic examination of the muscle biopsy over the right rectus femoris muscle revealed an increased number of fibers with centrally placed nuclei, type 1 fiber predominance, type 1 fiber atrophy, and a peripheral halo in the sarcoplasm on NADH-TR staining. On electron microscopy, central nuclei were separated by strands of glycogen and mitochondria. His muscle strength showed clinical improvement at a 14-month follow-up. This case illustrates the need for a muscle biopsy and histochemical staining and/or electron microscopic investigation for a proper diagnosis in hypotonic newborns with respiratory distress.
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PMID:Neonatal myotubular myopathy with respiratory distress: report of a case. 168 84

The authors report a seven-month-old boy with severe hypotonia, poor spontaneous movements, breathing difficulties and recurrent respiratory infections, dysmorphisms and a peculiar movement disorder: minipolymyoclonus (MPM), previously reported only in spinal muscular atrophies. MPM is characterized by nonrhythmic myoclonic jerks associated with a rhythmic tremor of the extended fingers polygraphically detected. A muscle biopsy showed pathological changes typical of congenital nemaline myopathy (CNM). The relationship between MPM and CNM may be explained on the presumptive basis of the "neurogenic" nature of this congenital myopathy or by the non-specificity of this clinical sign.
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PMID:Minipolymyoclonus in congenital nemaline myopathy: a nonspecific clinical marker of neurogenic dysfunction. 178 61

Myopathy may be associated with the syndrome of seroconversion in individuals infected by the human immunodeficiency virus (HIV) or may represent the initial symptom of AIDS. In 1990, 39-year old white, single homosexual who was admitted 1 month prior had experienced an episode of edema and pain in the left thigh that faded with the use of nonhormonal antiinflammatory drugs. 15 days later both forearms became enlarged accompanied by pain and erythema. Erythromycin and cefalexine were used without success. Intermittent fever started to appear before admission accompanied by dyspnea when straining. Examination showed tachypnea, oral candidiasis, and enlargement of both upper arms with pain and local erythema without articular involvement. Neurological examination revealed hypotonia and generalized hyperreflexia with intact muscle strength. Serology was positive for HIV, rheumatic activity tests were negative, and muscle biopsy indicated multifocal myonecrosis. Creatinine phosphokinase was 1019 IU (decrease to 44 IU after treatment), aldolase was 19 IU (decrease to 5.6 IU), and glutamic-pyruvic transminase was 50 IU (decrease to 22 IU). Radiography of the thorax indicated interstitial infiltration. Fiberoptic bronchoscopy indicated Pneumocystis carinii pneumonia. Sulfamethoxazole and trimetropim treatment cured the dyspnea and hypoxemia, but the enlargement of both arms progressed. Capillaroscopy indicated vasculitis that was treated without success with indomethacin (150 mg/day), for 7 days; prednisone (40-80 mg/day) for 10 days; and dexamethasone (280 mg/day) for 2 days. 6 days after methotrexate (50 mg/dose/week) treatment the fever disappeared and the enlargement in the extremities receded, but a lower dose of 7.5 mg caused the return of fever and edema in the right thigh. The myopathy remained asymptomatic for 5 months with a weekly dose of 15 mg of methotrexate.
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PMID:[AIDS and myopathy: report of a case and review of the literature]. 180 40

The X-linked recessive centronuclear/myotubular myopathy (XLR-CNM/MTM1), a severe neonatal disorder characterized by generalized hypotonia, muscle weakness and primary asphyxia, has recently been mapped to Xq28. This report presents linkage analysis data of eight families with X-linked centronuclear myopathy. Four probes from the region Xq26-27 and five Xq28 probes were used to get more precise gene localization and marker order. St14 (DXS52), fully informative in all families, shows significant linkage to the CNM gene (z = 3.60; theta = 0.05), followed by DX13 (DXS15) (z = 2.03; theta = 0.06) and F8 (z = 1.86; theta = 0.00). Combination of the physical map derived by Kenwrick and Gitschier (1989) and our linkage data lead to the most probable order R/GCP-G6PD-(XLR-CNM-F8)-p767-St14-cpX67-++ +DX13 placing the CNM gene close to F8. The results of this study confirm strong linkage of the CNM gene to the region Xq28 and will permit carrier testing and prenatal diagnosis in CNM families. We conclude that the precise localization of this devastating disorder may be of great importance for genetic counselling in families at risk. The lack of information about gene frequency and mutation rate as well as the severity and burden of the disease point to the inevitable need for accurate clinical diagnosis.
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PMID:X-linked centronuclear myopathy: mapping the gene to Xq28. 182 1

A diagnosis of infantile Pompe's disease (glycogenosis type II) was made by muscle biopsy on a 6-month-old infant boy seen with hypotonia, weakness, and developmental regression. Histochemistry and electron microscopy revealed a vacuolar myopathy with massive glycoge accumulation associated with increased neutral lipid as demonstrated on Oil Red O reactions. Pleomorphic, hypertrophic mitochondria with distortion of cristae and electron-dense deposits within the matrix were identified. Acid alpha-1,4-glucosidase activity was absent but associated with increased neutral maltase activity and a variable compensatory rise in activity of other lysosomal enzymes. Biochemical studies demonstrated low free carnitine, normal acylcarnitine, increased activity of carnitine palmityl and acyl transferases, and other enzymes of beta-oxidation with the notable exception of low normal beta-hydroxyacyl-CoA dehydrogenase activity. The explanation for the lipid accumulation is uncertain but is likely related to the combination of low carnitine concentration in muscle, low beta-hydroxyacyl CoA dehydrogenase, representing a rate limiting enzyme of beta-oxidation, and nonspecific defective mitochondrial function.
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PMID:Infantile Pompe's disease, lipid storage, and partial carnitine deficiency. 187 Jun 35


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