Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Emery-Dreifuss Muscular Dystrophy (EDMD) is an X-linked recessive muscular disorder characterized by early contractures of the elbows, Achilles tendons and postcervical muscles, slowly progressing muscle wasting and weakness and a cardiomyopathy characterized by conduction defects. Heart block is a frequent cause of death. Finding of mutations in one of the transcripts in the critical region in distal Xq28 led to the identification of the gene responsible for the disease. We now report the sequence of the gene which is 2100 bp long and the development of a set of primers to amplify and sequence the gene from patients' DNA. Eight unrelated X-linked familial cases were studied and they all carried different mutations, showing that lack of emerin in cardiac and skeletal muscle is the cause of the X-linked disease. No mutations were found in a family where the female carrier was affected nor in a sporadic case with a well established diagnosis of EDMD. Our findings suggest genetic heterogeneity of EDMD, and that at least two genes, the X-linked STA gene and one unidentified autosomal gene, are responsible for the disease.
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PMID:Identification of new mutations in the Emery-Dreifuss muscular dystrophy gene and evidence for genetic heterogeneity of the disease. 859 7

We report four patients, currently aged 15, 17, 19, and 42 years, with X-linked dystrophinopathy who presented with mental retardation (IQ range, 60-68) and psychiatric disturbance in the absence of muscle weakness. All patients had elevated serum creatine kinase and dystrophic changes on muscle biopsy. There were alterations in the size and abundance of dystrophin on immunohistochemistry and immunoblotting in all cases, consistent with a molecular diagnosis of Becker's muscular dystrophy. Two patients had deletions of the dystrophin gene on DNA analysis. These findings suggest that Becker's muscular dystrophy may be associated with a predominantly neuropsychiatric presentation and that dystrophinopathy should be considered in the differential diagnosis of unexplained cognitive or psychiatric disturbance in males. Serum creatine kinase may provide an adequate screening test in this clinical situation.
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PMID:Cognitive dysfunction as the major presenting feature of Becker's muscular dystrophy. 861 13

Hereditary spastic paraplegia (HSP) is a diverse group of inherited disorders characterized by progressive lower-extremity spasticity and weakness. Insight into the genetic basis of these disorders is expanding rapidly. Uncomplicated autosomal dominant, autosomal recessive, and X-linked HSP are genetically heterogeneous: different genes cause clinically indistinguishable disorders. A locus for autosomal recessive HSP is on chromosome 8q. Loci for autosomal dominant HSP have been identified on chromosomes 2p, 14q, and 15q. One locus (Xq22) has been identified for X-linked, uncomplicated HSP and shown to be due to a proteolipoprotein gene mutation in one family. The existence of HSP families for whom these loci are excluded indicates the existence of additional, as yet unidentified HSP loci. There is marked clinical similarity among HSP families linked to each of these loci, suggesting that gene products from HSP loci may participate in a common biochemical cascade, which, if disturbed, results in axonal degeneration that is maximal at the ends of the longest CNS axons. Identifying the single gene defects that cause HSPs distal axonopathy may provide insight into factors responsible for development and maintenance of axonal integrity. We review clinical, genetic, and pathologic features of HSP and present differential diagnosis and diagnostic criteria of this important group of disorders. We discuss polymorphic microsatellite markers useful for genetic linkage analysis and genetic counseling in HSP.
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PMID:Hereditary spastic paraplegia: advances in genetic research. Hereditary Spastic Paraplegia Working group. 864 38

A 28-year-old man had complaints of muscle weakness in both his legs and fingers. Moderate degrees of symmetrical atrophy adn weakness of the bilateral lower limbs, moderate degree of muscle atrophy was also noticed distal to the lower one third of the upper thigh. A moderate degree of weakness of the anterior tibial, extensor digitorum and peroneus muscles was also noted. Pes cavus deformity was evident bilaterally. Knee jerk was normal, and Achilles tendon reflex was absent without pathologic reflexes. He could not walk on his heels. Vibratory sensation was severely decreased in the toes, and both touch and pain sensations were slightly decreased on the dorsum of the feet. The median motor nerve conduction velocity was 28.9 m/sec with a prolonged distal latency. An amplitude of M-wave evoked by electrical stimulation of the median nerve 1 mV. No M-wave was obtained from stimulation of the tibial nerve, and no sensory nerve action potentials were elicited from electrical stimulation of the median and sural nerves. Histologic studies of the biopsied sural nerve revealed the occasional presence of internodes with a thin myelin sheath and a decrease in the density of large myelinated fibers. Small and atypical onion-bulbs were occasionally observed by electron microscopy. Based on the neurological examination and nerve conduction study of the family members, a sister, mother and grandmother of the proband were found to be mildly affected without any disability in their daily activities. However, the father and an uncle on the mother's side of the proband were normal. Therefore, we concluded clinically that this family had HMSN type I with autosomal dominant inheritance or X-linked HMSN. In the studies of fluorescence in situ hybridization and restriction fragment length polymorphism of the genomic DNA of the proband, a DNA duplication in chromosome 17p11.2-12 was not observed. A single-strand conformational polymorphism analysis of the genomic DNA encoding connexin32 (Cx32) revealed the abnormal band different from that of the control. A sequence analysis of the genomic DNA obtained by use of the polymerase chain reaction was also performed. It revealed that there was a mutant allele, a cytosine to thymine substitution of the nucleotide position 140, which caused a substitution of leucine for serine at amino acid position 26. The proband's mother was heterozygous for the mutant allele and the normal allele. This type of Cx32 mutation was different from any type of Cx32 mutation reported in the literature. The mutation in this family is located in the first transmembrane portion of Cx32, and may alter the function of Cx32 protein, as well as lead to the functional and structural abnormalities of the myelin sheath at the nodes of Ranvier and Schmidt-Lanterman's incisures, where Cx32 is present. This is the first Japanese X-linked HMSN family showing a new type of mutation of Cx32 gene with clinical findings and a histologic evaluation of the sural nerve.
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PMID:[A family of X-linked motor and sensory neuropathy with a new type of connexin32 mutation]. 866 24

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder primarily affecting young boys, often causing mental retardation in addition to the well-known progressive muscular weakness. Normal dystrophin expression is lacking in skeletal muscle and the CNS of both DMD children and the mdx mouse model. To date, 31P-magnetic resonance spectroscopy (MRS) has shown in vivo several abnormalities within skeletal muscle of mdx mice and DMD boys. In this study, we determined whether similar abnormalities occur in mdx brain in vivo by using 31P-MRS in addition to metabolite and enzyme analysis to study cerebral metabolism. An increased inorganic phosphate (P(i))/phosphocreatine (PCr) and pH was found in vivo for mdx brain compared with controls, and biochemical analysis showed a reduction in total creatine, an increased extracellular and decreased intracellular volume in mdx brain. No differences were found in any glycolytic or mitochondrial maximal enzyme activities. These changes are discussed with respect to the biochemical changes found in muscle from DMD patients and mdx mice. It is proposed that these biochemical changes may be a factor in the reduced cognitive capacity of mdx mice and some DMD children.
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PMID:Brain metabolism is abnormal in the mdx model of Duchenne muscular dystrophy. 867 81

X-linked myotubular myopathy (MTM1) is a severe congenital myopathy characterized by hypotonia, muscle weakness, and associated respiratory insufficiency. Perinatal death is common. The disease locus was shown to be linked to polymorphic markers in Xq28 and we have recently refined the MTM1 locus to a physical region of less than one megabase (Mb) at proximal Xq28. Two new microsatellite markers were developed and assigned in the MTM1 candidate region. We applied them and other DNA markers for prenatal diagnosis in two families. In one case, an affected fetus was predicted and a recombination event was observed with two more distal markers in the region. The second fetus was born unaffected as predicted. The new DNA markers and the precise location of the MTM1 gene provide an improvement for early prenatal diagnosis of the disease. We present suggestions for different combinations of linked and flanking DNA markers for maximal informativeness and accuracy.
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PMID:Prenatal diagnosis of X-linked myotubular myopathy: strategies using new and tightly linked DNA markers. 871 Jul 76

We studied two families with X-linked dominant Charcot-Marie-Tooth neuropathy. The clinical findings included onset around age 14 years, with moderate weakness of feet extensors and palmar and dorsal interossei, areflexia, distal hypesthesia, and slow progressivity. Motor nerve conduction velocities showed slowing (20 to 30 m/sec) and EMGs were normal. Genetic linkage analysis revealed positive lod scores with the markers of the Xq13.1 region in family 2, but was noninformative in family 1. There were no point mutations in the connexin32 gene coding region. Instead, family 1 revealed a T-to-G transversion at position -528 relative to the ATG start codon, whereas family 2 showed a C-to-T transition at position -458. The first mutation is located in the nerve-specific connexin32 promoter just upstream of the transcription start site, the second is located in the 5' untranslated region of the mRNA.
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PMID:Mutations of the noncoding region of the connexin32 gene in X-linked dominant Charcot-Marie-Tooth neuropathy. 875 34

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder primarily affecting young boys, often causing mental retardation in addition to the well-known progressive muscular weakness. Normal dystrophin expression is lacking in skeletal muscle and the central nervous system (CNS) of both DMD children and the mdx mouse model. The underlying biochemical lesion causing mental impairment in DMD is unknown. 1H-magnetic resonance spectroscopy (1H-MRS) detects choline-containing compounds, creatine and N-acetyl aspartate (NAA) in vivo. NAA is commonly used as a chemical marker for neurons, and a decline in NAA is thought to correlate with neuronal loss. Control mice were compared to mdx using a combination of in vivo and in vitro 1H-MRS methods to determine whether neural necrosis or developmental abnormalities occur in dystrophic brain. NAA levels were normal in mdx brain compared to controls suggesting minor, if any, neuronal necrosis in dystrophic brain. In contrast, choline compounds and myo-inositol levels were increased, indicative of gliosis or developmental abnormalities in dystrophic brain.
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PMID:An in vivo and in vitro H-magnetic resonance spectroscopy study of mdx mouse brain: abnormal development or neural necrosis? 888 Jun 86

Linkage analysis is described in a family with X-linked mental retardation, ataxia, weakness, floppiness, delayed motor development, absence of deep tendon reflexes, hearing impairment and loss of vision (MIM no. 301835). The disease has a fatal course due to the susceptibility of the patients to infections, especially of the respiratory tract. Clinical signs indicate impairment of the posterior columns, peripheral motor and sensory neurons and the second and eighth cranial nerves and/or their nuclei. The involvement of the posterior columns of the spinal cord is further suggested by the almost complete absence of myelinated fibers therein. We localized the responsible gene(s) to Xq21.33-q24 between DXS1231 and DXS1001 with a maximum lod score of 6.97. The proteolipid protein gene, which codes for two myelin proteins of the central nervous system and is located in this region, was considered as a candidate gene for this disorder. However, no mutations were found in the protein-coding part of this gene.
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PMID:Localization of the gene (or genes) for a syndrome with X-linked mental retardation, ataxia, weakness, hearing impairment, loss of vision and a fatal course in early childhood. 888 66

We report a 54-year-old man with X-linked bulbospinal muscular atrophy (BSMA) with bilateral abductor vocal cord paralysis. He noticed distal weakness in the lower limbs at age 20. In the following 18 years the weakness and atrophy of his leg muscles increased gradually. He has complained of stridors during respiratory tract infection and snored heavily during sleep since his age of 50. He was admitted to our hospital for the progressive stridors during meals. His two brothers were said to have similar complaints. Physical examination showed gynecomastia, hypertension and inspiratory stridor. Neurologic examination revealed distal muscular atrophy in his four extremities, especially more severe in bilateral lower limbs. Deep tendon reflexes were absent in all extremities. His tongue was slightly atrophic with fasciculation. Neurological diagnosis was made by family history, neurological findings, electromyography and a CAG repeat expansion in the androgen receptor gene. Lungs and diaphragm were normal on the chest radiograph. Cranial MRI including brain stem was also normal. Direct laryngoscopy showed a complete paralysis of both vocal cords in paramedian position. Tracheostomy was done right away; his respiratory distress showed prompt improvement after the tracheostomy. No previous report of bilateral vocal cord paralysis in BSMA has been found. Life expectancy in BSMA patients with vocal cord paralysis may be shortened because of respiratory distress or asphyxia. Of clinical importance is a careful assessment of vocal cord function in BSMA patients.
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PMID:[A case of X-linked bulbospinal muscular atrophy with bilateral abductor vocal cord paralysis]. 890 90


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