Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Paramyotonia congenita (PMC), a dominant disorder featuring cold-induced myotonia (muscle stiffness), has recently been genetically linked to a candidate gene, the skeletal muscle sodium channel gene SCN4A. We have now established that SCN4A is the disease gene in PMC by identifying two different single-base coding sequence alterations in PMC families. Both mutations affect highly conserved residues in the III-IV cytoplasmic loop, a portion of the sodium channel thought to pivot in response to membrane depolarization, thereby blocking and inactivating the channel. Abnormal function of this cytoplasmic loop therefore appears to produce the Na+ current abnormality and the unique temperature-sensitive clinical phenotype in this disorder.
 ...
PMID:Temperature-sensitive mutations in the III-IV cytoplasmic loop region of the skeletal muscle sodium channel gene in paramyotonia congenita. 131 Aug 98

Paramyotonia congenita (PC), an autosomal dominant non-progressive muscle disorder, is characterised by cold-induced stiffness followed by muscle weakness. The weakness is caused by a dysfunction of the sodium channel in muscle fibre. Parts of the gene coding for the alpha-subunit of the sodium channel of the adult human skeletal muscle (SCN4A) have been localised on chromosome 17. To investigate the role of this gene in the etiology of PC, a linkage analysis in 17 well-defined families was carried out. The results (zeta = 20.61, theta = 0.001) show that the mutant gene responsible for the disorder is indeed tightly linked to the SCN4A gene. The mutation causing hyperkalemic periodic paralysis (HyperPP) with myotonia has previously been mapped to this gene locus by the same candidate gene approach. Thus, our data suggest that PC and HyperPP are caused by allelic mutations at a single locus on chromosome 17.
 ...
PMID:Linkage data suggesting allelic heterogeneity for paramyotonia congenita and hyperkalemic periodic paralysis on chromosome 17. 166 29

The hyperkalemic periodic paralyses are a clinically heterogeneous group of autosomal dominant syndromes characterized by episodic paralysis associated with an elevated serum potassium level. Affected individuals in the same family tend to have homogeneous symptom complexes, although phenotypic variation is present among different families. For example, myotonia is absent in some pedigrees, present in others, and, in a third variant, paramyotonia congenita, myotonia coexists with cold-induced paralysis. Electrophysiological studies have demonstrated variant-specific abnormalities in skeletal muscle membrane sodium conductance. We tested the hypothesis that hyperkalemic periodic paralysis (without myotonia) and paramyotonia congenita are tightly linked to the tetrodotoxin-sensitive adult skeletal muscle sodium channel gene on chromosome 17q23-25 in two large pedigrees. The DNA polymorphisms detected in the growth hormone skeletal muscle sodium channel complex (GH1-SCN4A) and by flanking polymorphic markers (D17S74 and D17S40) demonstrated no recombinants between the disease phenotypes and this complex. Phenotypic variation in the hereditary hyperkalemic periodic paralyses may result from allelic heterogeneity at the tetrodotoxin-sensitive adult skeletal muscle sodium channel locus.
 ...
PMID:Paramyotonia congenita and hyperkalemic periodic paralysis are linked to the adult muscle sodium channel gene. 168 88

The single strand conformation polymorphism (SSCP) technique was used to screen genomic DNA of a family with myotonia aggravated by cold, potassium loading and suxamethonium, but without muscle weakness. An aberrant band was found in exon 24 of SCN4A, the gene encoding the adult skeletal muscle sodium channel alpha-subunit. DNA sequencing led to the detection of a G-to-A transition of cDNA nucleotide 4765 predicting a substitution of methionine for valine at position 1589 of the protein sequence. This amino acid is located within transmembrane segment S6 of channel repeat IV close to the cytoplasmic surface, a region which is supposed to act as acceptor of the inactivation gate of the channel. Four lines of evidence indicate that this mutation causes the disease: (i) the transition was only found for affected family members; (ii) no mutations were found in all other SCN4A exons; (iii) the affected gene region is conserved among various species; and (iv) an increase in the number of non-inactivating sodium channels had been revealed in earlier electrophysiological studies on an excised muscle specimen from the index patient. In addition, the close-by occurring substitution of valine for methionine at position 1592 known to cause hyperkalemic periodic paralysis was deduced for six families with the myotonic, non-dystrophic form of this disease.
 ...
PMID:A novel SCN4A mutation causing myotonia aggravated by cold and potassium. 824 56

The autosomal dominantly inherited phenotype of paramyotonia congenita (PC) without paralysis on exposure to cold MIM 168350) was originally described by De Jong in 1955. This phenotype is clearly different from classical paramyotonia congenita Eulenburg, which has been shown to be a sodium channelopathy resulting from mutations in the gene for the alpha-subunit of the human skeletal muscle sodium channel gene (SCN4A). From the clinical picture it has always been assumed that PC without paralysis to cold and PC Eulenburg are allelic disorders. In this study we present three German families with PC without cold paralysis, provide evidence that the disorder is linked to the SCN4A gene and report a novel SCN4A mutation (Val1293Ile) segregating in these families.
 ...
PMID:Paramyotonia congenita without paralysis on exposure to cold: a novel mutation in the SCN4A gene (Val1293Ile). 858 Apr 27

We report here a Japanese family with paramyotonia congenita. The proband was a 42-year-old woman (case 1), who noticed muscle stiffness and weakness in the cold since the age of 7 years. These symptoms were alleviated by warming. Her eldest son (case 2) also experienced similar symptoms, while her younger son and daughter were healthy. Neurological examination in case 1 revealed mild weakness in facial and neck muscles. Cold-induced muscle stiffness and weakness were present. Electromyography showed myotonic discharges, intensified by cooling or repetitive exercise. The amplitude of the compound muscle action potentials was also reduced by the repetitive exercise and cooling. Serum chemistry including potassium and CK was normal. Molecular analysis of SCN4A (exon22-24) by SSCP and nucleotide sequencing revealed a C-to-T transition at nucleotide 3,938, causing a substitution of 1313methionine of threonine in case 1. This mutation was confirmed by PCR-RFLP with a mismatched primer; the proband (case 1) and her eldest son (case 2) had a heterozygous mutation, while the other family members did not. This is the first report that a mutation in SCN4A was identified in a Japanese family with paramyotonia congenita.
 ...
PMID:[A Japanese family with paramyotonia congenita which has a mutation in the muscle sodium channel gene]. 866 33

Genetic analysis of the adult muscle sodium channel alpha-subunit, SCN4A gene on chromosome 17q, was performed by means of PCR technique in a Swedish family with paramyotonia congenita (Eulenburg) (PMC). The mutation was found in four family members and consisted of a C to T transition affecting the fourth domain of the sodium channel protein. This mutation has earlier been described in other families with paramyotonia congenita. All family members carrying the mutation had cold-induced paradoxical myotonia, myotonic bursts on EMG, and a type IIB atrophy on muscle biopsy. Three of them had slight CK elevation and two had episodes of paralysis. On the basis of clinical findings in this family, persistent proximal muscle weakness, myopathic EMG abnormalities, a type IIB atrophy on muscle biopsy and no symptoms but other signs of muscle affection, were earlier suggested as clinical features of PMC. However, genetic analysis revealed that family members with these symptoms and findings did not have the mutation, indicating that these features are not due to PMC.
 ...
PMID:C4342T-mutation in the SCN4A gene on chromosome 17q in a Swedish family with paramyotonia congenita (Eulenburg)--correlations with clinical, neurophysiological and muscle biopsy data. 919 4

The authors report a Japanese family with dominantly inherited heat-induced myotonia and cold-induced paralysis with hypokalemia. This phenotype is associated with a novel mutation in the voltage-dependent skeletal muscle sodium channel alpha subunit (SCN4A). This Pro1158Ser mutation is localized between the fourth and fifth transmembrane segments of domain III in SCN4A and may give rise to a new function; that is, thermosensitive permeability changes of the sodium channel.
 ...
PMID:Temperature-sensitive sodium channelopathy with heat-induced myotonia and cold-induced paralysis. 1085 91

A family with paramyotonia congenita (PC) is presented. At least 10 family members were affected in an autosomal dominant inheritance pattern. The proband had cold-sensitive muscle stiffness, paradoxical myotonia, and intermittent muscle weakness since childhood. The serum level of creatine kinase was mildly elevated and short exercise test with cooling revealed a drastic reduction of compound muscle action potentials with repetitive discharges. Muscle biopsy revealed marked variation in the fiber size and increased internal nuclei. The molecular biological study revealed a common missense mutation (Arg1448Cys) at the voltage-gated sodium channel gene (SCN4A). The repetitive CMAP discharges during short exercise test with cooling observed in the proband has not been reported previously. This observation needs to be confirmed among PC patients with different mutations. This is the first report on a PC family confirmed by the molecular biological technique in Korea.
 ...
PMID:A Korean family with Arg1448Cys mutation of SCN4A channel causing paramyotonia congenita: electrophysiologic, histopathologic, and molecular genetic studies. 1248 17

A 37-year-old Japanese woman was referred from another clinic to confirm the diagnosis of myotonia congenita. She had experienced cold-induced myotonia and muscle stiffness from early childhood. Of her three children, her elder son and her daughter have clinical features similar to hers. They experience neither grip nor percussion myotonia during warm weather, whereas myotonia is provoked by cold. Her younger son has no symptoms. DNA analyses of the SCN4A gene showed a C to T transition at nucleotide position 3938 in exon 22 of SCN4A (Thr1313Met) in all three affected family members, but not in the unaffected son. Paramyotonia congenita, the prevalence of which is very low in Japan, was diagnosed based on their clinical features and DNA analysis results.
 ...
PMID:Thr1313Met mutation in skeletal muscle sodium channels in a Japanese family with paramyotonia congenita. 1451 60


1 2 3 Next >>