Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myotonic dystrophy, a progressive autosomal dominant disorder, is associated with an expansion of a CTG repeat tract located in the 3'-untranslated region of a serine/threonine protein kinase, DMPK. DMPK modulates skeletal muscle Na channels in vitro, and thus we hypothesized that mice deficient in DMPK would have altered muscle Na channel gating. We measured macroscopic and single channel Na currents from cell-attached patches of skeletal myocytes from mice heterozygous (DMPK(+/-)) and homozygous (DMPK(-/-)) for DMPK loss. In DMPK(-/-) myocytes, Na current amplitude was reduced because of reduced channel number. Single channel recordings revealed Na channel reopenings, similar to the gating abnormality of human myotonic muscular dystrophy (DM), which resulted in a plateau of Na current. The gating abnormality deteriorated with increasing age. In DMPK(+/-) muscle there was reduced Na current amplitude and increased Na channel reopenings identical to those in DMPK(-/-) muscle. Thus, these mouse models of complete and partial DMPK deficiency reproduce the Na channel abnormality of the human disease, providing direct evidence that DMPK deficiency underlies the Na channel abnormality in DM.
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PMID:Skeletal muscle sodium channel gating in mice deficient in myotonic dystrophy protein kinase. 1100 35

Myotonic dystrophy (MD) is a genetically determined disease with autosomal dominant mode of inheritance. Relatively recently, MD has been divided into two sub-types (MD1 and MD2). Clinical symptoms of MD1 result from the expansion of a (CTG)n trinucleotide of the gene coding for serine/threonine protein kinase and clinical symptoms in MD2 are associated with the expansion of (CCTG)n in I intron of the zinc-finger protein 9 (ZNF9). Myotonic dystrophies MD1 and MD2 are multisystem diseases with numerous symptoms and high interfamily variability, resulting from the fact that different organs are affected. Until now the mechanisms that lead to the damage of the central and peripheral nervous systems, heart muscle and endocrine system have not been fully understood. Symptoms that are characteristic of MD1 and MD2 are myotonic symptom, muscular weakness and muscular atrophy. In MD2, muscular weakness and muscular atrophy are expressed more significantly in proximal segments, which is a differentiating factor for patients with MD1 who have muscular weakness and muscular atrophy in distal segments. Apart from myotonia and symptoms of skeletal muscle damage, the disease affects smooth muscles, heart muscle and the central nervous system, causing cataract, endocrine disorders, cognitive dysfunctions, intellectual and personality disturbances as well as sleep disordered breathing with nocturnal hypoventilation, obstructive, central and mixed apneas and hypopneas. The symptoms of sleep disordered breathing is fatigue, reduced cognitive performance and excessive daytime sleepiness. The pathophysiology of the breathing disorders includes weakness of the respiratory muscles and disorder of the respiratory drive. Of some interest are the works in which authors evaluated the incidence and character of abnormalities in the peripheral and central nervous systems. It has been shown that the number of CTG-repeats in the same person with MD1 is not stable over time and may increase, which leads to disease progression and new clinical symptoms. Cardiologic disorders associated with myotonic dystrophy are common and are part of the clinical picture of the disease. The dominant pathology are conduction disturbances and cardiac arrhythmias. It is estimated that 40 to 80% of patients with MD1 have abnormalities in ECG, and rapid supra-ventricular and ventricular cardiac arrhythmias are the second common cause of death in patients with MD1. Unfortunately, most of these pathologies are asymptomatic until life-threatening conduction blocks and/or supra-ventricular tachyarrhythmias occur. Sometimes, prodromal symptoms such as collapsing, fainting or feeling of palpitation occur and they should always draw attention of the treating doctor of a patient with muscular dystrophy. This paper is aimed at characterizing some common cardiologic and sleep related respiratory disorders of patients with myotonic dystrophy which if not recognized in good time may lead to sudden death.
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PMID:[Cardiac, respiratory and sleep disorders in patients with myotonic dystrophy]. 2051 7