Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myotonic dystrophy type 2 (DM2) is a clinically but not genetically heterogeneous, multisystem disorder, that is clinically similar to, but distinct from myotonic dystrophy type 1 (DM1). Initially, different phenotypes of DM2 were described by Ricker (proximal myotonic myopathy, PROMM), Ranum (myotonic dystrophy 2, DM2) and Udd (proximal myotonic dystrophy, PDM). Clinical features these three phenotypes had in common were diffuse, proximal or distal weakness, wasting, myotonia, cataract, cerebral, endocrine and cardiac abnormalities. Initially, the clinical differences between DM1 and PROMM seemed unmistakable, but meanwhile it has become apparent that the clinical differences between these entities are blurring. In 1999, Day et al., Meola et al. and Ricker et al. mapped the mutated gene of all three phenotypes to chromosome 3q. In 2001, the three different phenotypes were found to rely on the same mutation in the ZNF9 gene on chromosome 3q21.3. Although DM2 may be clinically heterogeneous, it is by result of a mutation in a single gene. The mutation responsible for DM2 is a CCTG-repeat expansion of 75-11 000 repeats in intron 1 of the ZNF9 gene on chromosome 3q21.3. Because of the clinical heterogeneity, the diagnosis of DM2 should rely on DNA analysis alone.
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PMID:Myotonic dystrophy type 2. 1222 Mar 74

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

Myotonic dystrophy is an autosomal dominant, multisystem disorder that is characterized by myotonic myopathy. The symptoms and severity of myotonic dystrophy type l (DM1) ranges from severe and congenital forms, which frequently result in death because of respiratory deficiency, through to late-onset baldness and cataract. In adult patients, cardiac conduction abnormalities may occur and cause a shorter life span. In subsequent generations, the symptoms in DM1 may present at an earlier age and have a more severe course (anticipation). In myotonic dystrophy type 2 (DM2), no anticipation is described, but cardiac conduction abnormalities as in DM1 are observed and patients with DM2 additionally have muscle pain and stiffness. Both DM1 and DM2 are caused by unstable DNA repeats in untranslated regions of different genes: A (CTG)n repeat in the 3'-UTR of the DMPK gene and a (CCTG)n repeat in intron 1 of the CNBP (formerly ZNF9) gene, respectively. The length of the (CTG)n repeat expansion in DM1 correlates with disease severity and age of onset. Nevertheless, these repeat sizes have limited predictive values on individual bases. Because of the disease characteristics in DM1 and DM2, appropriate molecular testing and reporting is very important for the optimal counseling in myotonic dystrophy. Here, we describe best practice guidelines for clinical molecular genetic analysis and reporting in DM1 and DM2, including presymptomatic and prenatal testing.
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PMID:Best practice guidelines and recommendations on the molecular diagnosis of myotonic dystrophy types 1 and 2. 2264 81