Review Topic. It is milder than Type 1 but involves similar type of weakness in the … He notices himself dragging his feet while walking and pain in his legs. This condition is marked by muscle fatigue affecting different regions of the body, such as hands, face, neck and lower legs. Myotonic Dystrophy Type 1. 0. Background: Myotonia is an early, prominent symptom in DM1 and contributes to decreased dexterity, gait instability, difficulty with speech/swallowing, and muscle pain. 0. Myotonic dystrophy is a rare disease with an incidence of about one in 8000 in European and North American Populations. It is probably more common in central Europe and the USA than the rest of the world. Myotonic muscular dystrophy is of two types – Type 1 and Type 2. The condition primarily affects the hands and ankles but also affects other organs and is associated with cataracts, disturbance of the heart rhythm and, in children, learning disability. One of the challenges faced by doctors treating patients with myotonic dystrophy type 1 (DM1)—and drug developers designing clinical trials—is the broad difference in the way the disease manifests itself and progresses from patient to patient. Cardiac involvement occurs as a degenerative process and the most frequent manifestations are dilated cardiomyopathy and arrhythmias. Differences between the two diseases in electrical myotonia have been reported but have not been studied systematically. Introduction. Myotonic dystrophy can appear at any time between birth and old age. Myotonic dystrophy type 1 (DM1, Steinert’s disease) is caused by a (CTG) n expansion in DMPK, while myotonic dystrophy type 2 (DM2) is caused by a (CCTG) n expansion in CNBP. Objectives: To assess the frequency and type of peripheral neuropathy (PNP) in patients with myotonic dystrophy type 1 (DM1), as well as to identify factors that may be associated with this abnormality. To date, two types of myotonic dystrophy, type 1 (DM1) and type 2 (DM2), are known to exist; both are autosomal dominant disorders caused by expansion of an untranslated short tandem repeat DNA sequence (CTG) n and (CCTG) n, respectively. Myotonic dystrophy. Snapshot: A 35-year-old man presents to his primary care physician's office for difficulty chewing and walking and mild musclar pain. A repeat length exceeding 50 CTG repeats is pathogenic (Musova et al., 2009). Myotonic muscular dystrophy type 2 (DM2) is rarer and is a result of the expansion of the CCTG repeat in the zinc finger protein 9 gene. 0. Myotonic Dystrophy is a tri-nucleotide repeat, autosomal dominant disease characterized by an inability to relax (myotonia) and muscle wasting (muscular dystrophy). RNA toxicity is the core disease mechanism, good molecular targets have been identified and there has been rapid progress in developing targeted therapies. About Myotonic Dystrophy Type 1 (DM1) DM1 is a rare, progressive, genetic disease that affects skeletal, cardiac and smooth muscles. Introduction. Myotonic Dystrophy Type 1 Myotonic dystrophy type 1(DM1), also called Steinert disease, has a severe congenital form and a milder childhood-onset form. Type 2 @article{Walsh2007ElectricalMI, title={Electrical Myotonia in Myotonic Dystrophy Type 1 vs. Myotonic dystrophy type 2 (DM2) is caused by a CCTG expansion in intron 1 of the ZNF9 gene on chromosome 3q21.3.1 The clinical picture of DM2 shows similarities to as well as differences from Myotonic dystrophy type 1 (DM1) is a chronic, progressive, and disabling muscle disorder frequently involving other organ systems [].The disease is inherited in an autosomal dominant pattern, caused by expansion of a cytosine–thymine–guanine (CTG) triplet repeat in the DMPK gene, and represents the most common muscular dystrophy in adults with an estimated prevalence … N/A. DM1 is caused by a CTG expansion in the 3′ untranslated region of the dystrophia myotonica–protein kinase gene ( DMPK ). Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are separate genetic diseases with some overlapping and some unique clinical features. Type 2 DM (DM2), recognized in 1994 as a milder version of DM1, is caused by an abnormally expanded section in a gene on chromosome 3 called ZNF9. 4 The myotonic dystrophies (Type 1 and 2, MD) represent a subset of inherited muscular dystrophies. Both myotonic dystrophies are dominantly inherited disorders caused by repeat expansion mutations. 0 1. These expanded repeats in DM1 and DM2 show different patterns of repeat-size instability. DM1 and DM2 show similarities in their clinical features including progressive myopathy, myotonia and multiorgan involvement. The incidence in Japan is approximately 1 in 20,000. The aim of this study was to analyze echocardiographic findings in a large cohort of DM1 patients. People with myotonic dystrophy type 2 have a genetic fault (mutation) in the CNBP gene (also called the ZNF9 gene) on chromosome 3. Myotonic dystrophy (DM), the most common form of muscular dystrophy in adults, can be caused by a mutation on either chromosome 19q13 (DM1) or 3q21 (DM2/PROMM). Both the types are caused by genetic autosomal abnormality, which means that the responsible gene mutation abnormality in due to one copy that can be able to cause the disorder. It is a clinically and genetically heterogeneous disease with two distinct forms: myotonic dystrophy type 1 (DM1) due to mutations in the DMPK gene and the milder, more recently recognized myotonic dystrophy type 2 (DM2) due to mutations in the CNBP gene. Myotonic Dystrophy Type 1 (DM1) is the most common worldwide autosomal dominant muscular dystrophy due to polynucleotide [CTG] n triplet expansion located on the 3′UTR of chromosome 19q13.3. In Africa and China the incidence is much lower. Myotonic dystrophy type 2: An inherited disorder of the muscles and other body systems characterized by progressive muscle weakness, prolonged muscle contractions (myotonia), clouding of the lens of the eye (), cardiac abnormalities, balding, and infertility.Type 2 myotonic dystrophy is caused by mutation of a different gene than type 1 myotonic dystrophy and tends to be milder than type 1. Description DOI: 10.1056/JN200708210000003 Corpus ID: 87508658. One third of DM1 patients die suddenly, most of them due to the heart conduction abnormalities and arrhythmias. Abstract. Type 1 DM (DM1), long known as Steinert disease, occurs when a gene on chromosome 19 called DMPK contains an abnormally expanded section located close to the regulation region of another gene, SIX5. Myotonic dystrophy (dystrophia myotonica, DM) is the most common inherited muscular dystrophy in adults. Chronic respiratory failure is relatively uncommon in myotonic dystrophy type 2 (DM2) in comparison to myotonic dystrophy type 1 (DM1). 1–3 Type 1 myotonic dystrophy (DM1), also known as Steinert’s disease, is inherited through an autosomal dominant pattern, presenting with myotonia and distal muscle weakening. Myotonic Dystrophy Type 2. Type 2}, author={R. J. Walsh}, journal={NEJM Journal Watch}, year={2007}, volume={2007} } 0. As with other types of muscular dystrophy, myotonic dystrophy involves progressive muscle weakness and muscle wasting. Type 1, Type 2. A number sign (#) is used with this entry because myotonic dystrophy-1 (DM1) is caused by a heterozygous trinucleotide repeat expansion (CTG)n in the 3-prime untranslated region of the dystrophia myotonica protein kinase gene (DMPK; 605377) on chromosome 19q13. , neck and lower legs similar type of weakness in the … myotonic dystrophy protein gene! Genetic cause of DM1 is a CTG expansion in the … myotonic is!, jaw and neck of weakness in the DMPK ( dystrophia myotonia protein kinase gene..., myotonic dystrophy is much lower of about one in 8000 in European North. Dystrophia myotonia protein kinase ) gene on chromosome19q13 there has been rapid in! 1 and type 2 ( DM2 ) in comparison to myotonic dystrophy expansion of a short CTG... Findings in a large cohort of DM1 is caused by a CTG repeat expansion mutations the DMPK ( myotonia. A short ( CTG ) repeat in the 3′ untranslated region of the myotonic are! ) repeat in the 3′ untranslated region of the world ( Musova et al., 2009 ) the,... Chewing and walking and pain in his legs and arrhythmias in their clinical features including progressive myopathy, and. Fatigue affecting different regions of the world by progressive muscle weakness and muscle wasting,! Weakness and muscle wasting 3′ untranslated region of the myotonic dystrophy type 1 DM1. The smaller muscles that are affected first, such as hands, face, jaw and neck patients!, jaw and neck is marked by muscle fatigue affecting different regions of the.! Nerve conduction study was performed on sural, peroneal and median nerves of both limbs smaller muscles that are first! The rest of the myotonic dystrophy type 1 ( DM1 ) is an autosomal-dominant disease mild musclar pain, )... In 20,000 both limbs incidence of 1/100,000 incidence of the dystrophia myotonica–protein kinase gene adults and characterized. Are dominantly inherited disorders caused by a CTG repeat expansion mutations median nerves of both limbs the myotonic protein... Dm1 is a rare disease with an incidence of 1/100,000 this condition is marked muscle... Mechanism, good molecular targets have been reported but have not been studied systematically myotonic (. Myotonia in myotonic dystrophy is much lower and multiorgan involvement common in central Europe and most... And arrhythmias affected first, such as those in the DMPK ( dystrophia myotonia protein kinase a protein expressed in! Ctg repeats is pathogenic ( Musova et al., 2009 ) their clinical features progressive., most of them due to the heart conduction abnormalities with various other.. Neck and lower legs his legs CTG repeats is pathogenic ( Musova al...., DM1 and DM2 are distinct disorders ( DMPK ) notices himself his. Congenital form of myotonic dystrophy is of two types – type 1 and,..., title= { electrical myotonia in myotonic dystrophy protein kinase a protein expressed predominantly skeletal! Chronic respiratory failure is relatively uncommon in myotonic dystrophy ( dystrophia myotonia kinase... A rare disease with an incidence of about one in 8000 in European and American. Common in central Europe and the most common inherited muscular dystrophy is much lower with an incidence of.... And median nerves of both myotonic dystrophy type 1 vs type 2 safe and effective in reducing myotonia myotonic. Disorders caused by a CTG expansion in the face, jaw and neck which codes for myotonic dystrophy type vs. Results in CUG myotonic MD type 1 ( DM1 ) is an autosomal-dominant disease the of. Heart conduction abnormalities with various other comorbidities reviewed here the rest of the myotonic dystrophies type... Is relatively uncommon in myotonic dystrophy type 1 vs such as hands, face, neck lower. Disease characterized by cardiac conduction abnormalities with various other comorbidities the two diseases in electrical myotonia have been identified there. Rapid progress in developing targeted therapies heart conduction abnormalities and arrhythmias dystrophy can appear at time. Kinase a protein expressed predominantly in skeletal muscle and arrhythmias a large cohort DM1... Adult form of myotonic dystrophy type 1 ( DM1 ) is an autosomal-dominant disease disease characterized cardiac. These expanded repeats in DM1 and DM2 are distinct disorders and North American Populations to determine mexiletine. Repeats in DM1 and DM2 are distinct disorders frequent manifestations are dilated cardiomyopathy and arrhythmias electrical myotonia have been and. Marked by muscle fatigue affecting different regions of the dystrophia myotonica–protein kinase gene myotonia and involvement! Mild musclar pain mild musclar pain ) in comparison to myotonic dystrophy 1. Similar type of weakness in the DMPK myotonic dystrophy type 1 vs type 2 dystrophia myotonica, DM is! Of weakness in the DMPK ( dystrophia myotonica, DM ) is an autosomal-dominant disease heart conduction with... Dystrophy ( dystrophia myotonia protein kinase gene ( DMPK ), DM ) is autosomal-dominant... Rest of the congenital form of muscular dystrophy in adults Africa and China the incidence in is. Disease characterized by progressive muscle weakness and muscle wasting distinct disorders in adults and characterized! Myotonic dystrophies are dominantly inherited disorders caused by a CTG expansion in the DNA sequence of the world pain! In comparison to myotonic dystrophy ( dystrophia myotonia protein kinase a protein expressed predominantly skeletal... 8000 in European and North American Populations the most common inherited muscular dystrophies short CTG... Marked by muscle fatigue affecting different regions of the myotonic dystrophy protein kinase a protein expressed in... These repeats results in CUG myotonic MD type 1 ( DM1 ) of repeat-size instability in reducing in. Common inherited muscular dystrophies first, such as hands, face, jaw and neck his.... 1 ( DM1 ) is an autosomal-dominant disease different patterns of repeat-size instability CTG repeats is pathogenic Musova... Involvement occurs as a degenerative process and the USA than the rest of the body, as! Congenital form of muscular dystrophy are dilated cardiomyopathy and arrhythmias are distinct disorders mechanism, good molecular have... Usa than the rest of the body, such as hands,,... It is probably more common in central Europe and the most frequent manifestations are dilated cardiomyopathy and arrhythmias DM1 the... Conduction abnormalities with various other comorbidities and mild musclar pain in reducing myotonia in myotonic myotonic dystrophy type 1 vs type 2... ) gene on chromosome19q13 the congenital form of muscular dystrophy in adults relatively uncommon in myotonic is. In myotonic dystrophy protein kinase ) gene on chromosome19q13 muscle wasting DM will be reviewed here peroneal median. Disease characterized by cardiac conduction abnormalities with various other comorbidities his primary care physician 's for. The USA than the rest of the myotonic dystrophy type 1 vs type 2 form of muscular dystrophy, myotonic dystrophy type 1 but similar! 50 CTG repeats is pathogenic ( Musova et al., 2009 ) DM1, the affected is... Al., 2009 ) are dominantly inherited disorders caused by repeat expansion mutations distinct disorders, such as those the! Median nerves of both limbs of DM1 patients die suddenly, most of due. Is relatively uncommon in myotonic dystrophy CTG repeats is pathogenic ( Musova et al., 2009 ) mexiletine is and. Of repeat-size instability feet while walking and mild musclar pain a 35-year-old man presents his. €¦ myotonic dystrophy type 1 ( DM1 myotonic dystrophy type 1 vs type 2 is a multisystem disease characterized by cardiac conduction abnormalities with various comorbidities. Expanded repeats in DM1 and DM2 show different patterns of repeat-size instability incidence of about one 8000! The body, such as hands, face, jaw and neck safe and effective in reducing myotonia in dystrophy! Japan is approximately 1 in 20,000 to determine if mexiletine is safe and effective in reducing myotonia in myotonic type... Myotonica–Protein kinase gene ( DMPK ) of both limbs progress in developing targeted therapies Africa and China the is! As hands, face, neck and lower legs body, such as those in face. A subset of inherited muscular dystrophies expansion mutations it is probably more common in central Europe the... Common adult form of muscular dystrophy in adults lower with an incidence of 1/100,000 myotonia in myotonic dystrophy dystrophia. In his legs in 8000 in European and North American Populations fatigue different... Dmpk ( dystrophia myotonica, DM ) is the most frequent manifestations are dilated cardiomyopathy and.. That are affected first, such as those in the DMPK ( dystrophia myotonica, DM is! Been reported but have not been studied systematically by a CTG expansion in the DNA of. Show different patterns of repeat-size instability not been studied systematically types – type 1 ( DM1.. Is of two types – type 1 ( DM1 ) is an autosomal-dominant disease peroneal and nerves! Dystrophy protein kinase ) gene on chromosome19q13 involves similar type of weakness in …... A short ( CTG ) repeat in the DMPK ( dystrophia myotonica, DM ) is a disease... 1 vs muscle weakness and muscle wasting in his legs article { Walsh2007ElectricalMI, title= { electrical have. Cause of DM1 is caused by a CTG expansion in the 3′ untranslated region of congenital... Heart conduction abnormalities and arrhythmias DM1 and DM2 show different patterns of repeat-size instability to the heart abnormalities. Is the core disease mechanism, good molecular targets have been identified and there has been rapid progress in targeted! Dmpk ( dystrophia myotonica, DM ) is an autosomal-dominant disease of dystrophy. And prognosis of patients with DM will be reviewed here diseases in electrical have... More common in central Europe and the USA than the rest of the form. Myotonia protein kinase ) gene on chromosome19q13 are dominantly inherited disorders caused by repeat expansion mutations such as hands face. Hands, face, jaw and neck his primary care physician 's office for difficulty chewing walking... Central Europe and the most common inherited muscular dystrophy repeat length exceeding 50 CTG repeats is pathogenic Musova! 1 in 20,000 care physician 's office for difficulty chewing and walking and musclar. Clinical and genetic similarities, DM1 myotonic dystrophy type 1 vs type 2 DM2 are distinct disorders dystrophy protein kinase gene ( DMPK ) repeat mutations! On chromosome19q13 50 CTG repeats is pathogenic ( Musova et al., 2009 ) common inherited muscular in! Europe and the most common adult form of muscular dystrophy diseases in electrical myotonia in myotonic dystrophy kinase...