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)

Mitochondrial DNA depletion is a quantitative disorder of mtDNA, characterized by tissue-specific reductions in mtDNA copy number, that presents in infancy or early childhood. It is most likely transmitted as an autosomal recessive trait, although about half of the described cases are sporadic. To estimate its prevalence we measured relative mtDNA copy number (mtDNA: 18S rDNA ratio) by Southern blot analysis in muscle biopsy samples from all children with compatible histories referred between 1983 and 1994. Of the 304 biopsies evaluated, 54 met the study criteria. We found 6 patients (2 male, 4 female) with mtDNA depletion (relative mtDNA copy number 7.9-33.2% of control). Their clinical course and findings were heterogeneous, however all but one manifested weakness, hypotonia, and developmental delay. Clinical severity was not obviously related to the degree of mtDNA depletion. No patient had ragged-red fibers, although 2 had a lipid storage myopathy. Immunofluorescence with antibodies to double-stranded DNA, COX IV, and COX II demonstrated homogeneously reduced reactivity to all three antibodies compared with control. mtDNA depletion may be a relatively common neurogenetic disorder of infancy and early childhood and should be considered in children with unexplained weakness, hypotonia, or developmental delay.
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PMID:Mitochondrial DNA depletion: prevalence in a pediatric population referred for neurologic evaluation. 873 3

A 5-year-old girl diagnosed with biotinidase deficiency at 9 months of age demonstrated limb and axial hypotonia which improved on biotin therapy. In this patient, electromyographic (EMG) studies prior to treatment were compatible with a mild myopathic process. Serial EMGs performed on biotin therapy demonstrated a gradual resolution of the myopathy. This is the first documented case of a reversible myopathy in a patient with biotinidase deficiency, which may contribute to the clinical findings of hypotonia.
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PMID:Reversible metabolic myopathy in biotinidase deficiency: its possible role in causing hypotonia. 875 Jun 7

We present the clinical and morphological findings in a case of progressive congenital myopathy. The symptoms present at birth included severe general muscular hypotonia, diffuse muscular atrophy, arthrogryposis, absence of spontaneous movements, and left ventricular hypertrophy. A biopsy specimen taken from the gastrocnemius muscle when the patient was 2 weeks old revealed deposits which consisted of actin filaments as shown by electron microscopy. The infant was occasionally respirator dependent but was mostly able to breathe unassisted. At the age of 5 months he died of respiratory failure. The actin filament deposits may explain the clinical findings.
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PMID:Fatal congenital myopathy with actin filament deposits. 881 Nov 33

Children frequently undergo muscle biopsy for the workup of hypotonia under general anaesthesia which poses unique risks in patients with undiagnosed muscle disease. Mitochondrial myopathies are a relatively newly recognized cause of myopathy and multisystem disease in both adults and children. The diagnosis is complex. In addition to causing myopathy, there are metabolic derangements present in some cases that may be life-threatening. We present three cases of children with hypotonia where the diagnosis was suspected in two patients, and confirmed in the third. The question of whether patients with mitochondrial myopathies are at increased risk for developing malignant hyperthermia is discussed.
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PMID:Mitochondrial myopathies: an unusual cause of hypotonia in infants and children. 882 50

Hypotonia and weakness developed in a 12-month-old boy whose psychomotor development had previously been normal. The muscle biopsy demonstrated a disparity in the mean diameters of type 1 and type 2 fibers and satisfied major histologic criteria for diagnosis of congenital fiber type disproportion (CFTD). However, deterioration of motor and mental function, which developed subsequently, strongly suggested progressive encephalopathy. Examination of leukocyte cerebral enzymes at 15 months of age revealed a complete lack of galactosylceramide-beta-galactosidase. Selective type 1 fiber atrophy with type 1 fiber predominance has been observed in various conditions, including Krabbe disease. We report an additional case of Krabbe leukodystrophy associated with CFTD. The finding on the molecular level will resolve the dilemma of whether CFTD is a congenital myopathy or whether these patterns of disproportion may result from a number of different processes that interfere with the maturation of the developing motor unit.
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PMID:Association of Krabbe leukodystrophy and congenital fiber type disproportion. 885 9

X-linked recessive myotubular myopathy (XLMTM) is a severe neonatal neuro-muscular disease characterized by muscle weakness, hypotonia, and respiratory problems. The locus for the XLMTM gene (MTM1) has previously been mapped to Xq28 between the markers DXS304 and DXS497 by linkage analyses and by determining the breakpoints of deletion patients. We report linkage analysis data or 20 XLMTM families who were tested using the DNA markers DXS1113, DXS304, DXS455, DXS1684, DXS305 and DXS52 and present two families showing recombination between MTM1 and either DXS304, DXS334 or DXS305. We found each of the families to be informative for at least three markers. Based on these findings we excluded 30 women from being carriers, the carrier status of 17 obligate carrier mothers could be confirmed and eight mothers and sisters were identified as to be at high risk of carrying a MTM1 mutation. By combining recently published data with the results of our recombinant families, we suggest that the MTM1 locus maps between DXS334 and DXS497 narrowing the region of interest from 600 kb to an estimated < 500 kb interval. This additional refinement in the localization of MTM1 means a further step towards the isolation of the gene in the near future, and allows more reliable and efficient carrier detection and prenatal diagnosis.
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PMID:X-linked myotubular myopathy: refinement of the critical gene region. 888 57

The severe neonatal centronuclear/myotubular myopathy (XLMTM) is an X-linked disorder characterized by generalized muscle weakness, hypotonia and serious respiratory insufficiency. The gene for this disease has been assigned to the long arm of chromosome X in the Xq28 band. Ca2+ ATPase isoform-3 (ATP2B3) has also been mapped to the human Xq28 region. Moreover, it is expressed in fetal but not in adult muscle, suggesting the developmental regulation of gene transcription. These findings render the ATP2B3 gene as an interesting candidate gene for XLMTM. Four families and 7 unrelated XLMTM patients have been analysed by using cDNA and genomic probes of ATP2B3. No large deletions or duplications have been found but a new EcoRI polymorphism has been identified. In addition, the DNA of an XLMTM male deletion patient has been hybridized with the ATP2B3 gene sequences. Our results therefore support the exclusion of ATP2B3 as the causal disease gene of XLMTM. The isolation of the MTM1 gene has recently been reported by another group. However, our approach has led to the detection of a new polymorphism that is an informative marker for linkage and mutation studies in other Xq28-mapped neurological or neuromuscular disorders.
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PMID:Detection of a new polymorphism in the plasma-membrane Ca2+ ATPase isoform-3 gene and its exclusion as a candidate for X-linked myotubular myopathy (MTM1). 893

We report a baby boy, the third child of a nonconsanguineous couple, with congenital myotubular myopathy. At birth, he had generalized hypotonia and respiratory distress. On physical examination, an elongated apathetic face, high-arched palate, bilateral ptosis, funnel chest, frog-leg posture, little spontaneous movement of the limbs and areflexia were observed. A chest x-ray revealed thin ribs and clavicles. The infant died 54 days after birth despite intensive management. The mother, a healthy 32-year-old female, displayed myotubes on muscle biopsy which suggested an X-linked recessive inheritance pattern for myotubular myopathy. This report illustrates the importance of taking a detailed family history as well as a muscle biopsy in the diagnosis of X-linked recessive myotubular myopathy.
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PMID:X-linked recessive myotubular myopathy proven by muscle biopsy. 906 5

This study was conducted in order to elucidate the rarely mentioned diagnosis of benign congenital hypotonia (BCH), introduced by Walton in 1956. A clinical follow-up examination was made of 10 patients who 6-18 months earlier were diagnosed as having BCH. In two cases the initial diagnosis proved to be incorrect since a specific origin was found for the hypotonia (Dubowitz myopathy and coeliac disease). In the remaining eight cases the muscular tones was either completely normalized (two children) or considerably improved. It is conducted that BCH is a clinical diagnosis with a good prognosis. If a hypotonic child meets the criteria of BCH as described by Shuper in 1981, a safe strategy would be to refer for physiotherapy and follow the child to make sure that the hypotonia decreases as expected. If it has not disappeared at age three to four years, further investigations should be made. Finally, it should be emphasized that even though the hypotonia always decreases, it will not always disappear completely.
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PMID:[Benign congenital hypotonia]. 922 88

Three unrelated young children are reported to have suffered since birth from muscle hypotonia and two of them from fatal respiratory insufficiency. Muscle tissues were found to contain large masses of thin myofilaments, immunologically identified as containing actin, but without further morphological features. These masses of thin filaments were found in different muscles at different occasions in the three children, suggesting a disease-specific morphological and possibly nosological feature all of them justifying classification as congenital myopathy with excess of actin or actin myopathy. The lesions were dissimilar to hyaline bodies in that the latter consist of granular material which is faintly positive for ATPase activity whereas the masses of thin filaments are devoid of ATPase activity. Two of our three patients also had intranuclear rods with virtually no sarcoplasmic rods suggesting the term of this congenital myopathy as actin myopathy with intranuclear rods.
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PMID:Congenital myopathy with excess of thin myofilaments. 918 79


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