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Steinert myotonic dystrophy syndrome(DM1)

MedGen UID:
10239
Concept ID:
C0027126
Disease or Syndrome
Synonyms: DM1; DYSTROPHIA MYOTONICA; DYSTROPHIA MYOTONICA 1; Dystrophia myotonica type 1; Myotonic Dystrophy; MYOTONIC DYSTROPHY 1; Myotonic dystrophy type 1; Steinert disease; Steinert myotonic dystrophy; Steinert's disease
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Autosomal dominant inheritance refers to genetic conditions that occur when a mutation is present in one copy of a given gene (i.e., the person is heterozygous).
SNOMED CT: Myotonic dystrophy (77956009); DM - Dystrophia myotonica (77956009); Myotonia dystrophica (77956009); Steinert myotonic dystrophy syndrome (77956009); Steinert syndrome (77956009); Dystrophia myotonica (77956009)
 
Gene (location): DMPK (19q13.32)
OMIM®: 160900
Orphanet: ORPHA206647

Disease characteristics

Excerpted from the GeneReview: Myotonic Dystrophy Type 1
Myotonic dystrophy type 1 (DM1) is a multisystem disorder that affects skeletal and smooth muscle as well as the eye, heart, endocrine system, and central nervous system. The clinical findings, which span a continuum from mild to severe, have been categorized into three somewhat overlapping phenotypes: mild, classic, and congenital. Mild DM1 is characterized by cataract and mild myotonia (sustained muscle contraction); life span is normal. Classic DM1 is characterized by muscle weakness and wasting, myotonia, cataract, and often cardiac conduction abnormalities; adults may become physically disabled and may have a shortened life span. Congenital DM1 is characterized by hypotonia and severe generalized weakness at birth, often with respiratory insufficiency and early death; intellectual disability is common.  [from GeneReviews]
Full text of GeneReview (by section):
Summary  |  Diagnosis  |  Clinical Characteristics  |  Differential Diagnosis  |  Management  |  Genetic Counseling  |  Resources  |  Molecular Genetics  |  References  |  Chapter Notes
Authors:
Thomas D Bird   view full author information

Additional descriptions

From OMIM
Myotonic dystrophy is an autosomal dominant disorder characterized mainly by myotonia, muscular dystrophy, cataracts, hypogonadism, frontal balding, and ECG changes. The genetic defect in DM1 results from an amplified trinucleotide repeat in the 3-prime untranslated region of a protein kinase gene. Disease severity varies with the number of repeats: normal individuals have 5 to 37 repeats, mildly affected persons have 50 to 150 repeats, patients with classic DM have 100 to 1,000 repeats, and those with congenital onset can have more than 2,000 repeats. The disorder shows genetic anticipation, with expansion of the repeat number dependent on the sex of the transmitting parent. Alleles of 40 to 80 repeats are usually expanded when transmitted by males, whereas only alleles longer than 80 repeats tend to expand in maternal transmissions. Repeat contraction events occur 4.2 to 6.4% of the time (Musova et al., 2009). Genetic Heterogeneity of Myotonic Dystrophy See also myotonic dystrophy-2 (DM2; 602668), which is caused by mutation in the ZNF9 gene (116955) on chromosome 3q.  http://www.omim.org/entry/160900
From GHR
Myotonic dystrophy is part of a group of inherited disorders called muscular dystrophies. It is the most common form of muscular dystrophy that begins in adulthood. Myotonic dystrophy is characterized by progressive muscle wasting and weakness. People with this disorder often have prolonged muscle contractions (myotonia) and are not able to relax certain muscles after use. For example, a person may have difficulty releasing their grip on a doorknob or handle. Also, affected people may have slurred speech or temporary locking of their jaw. Other signs and symptoms of myotonic dystrophy include clouding of the lens of the eye (cataracts) and abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects). In affected men, hormonal changes may lead to early balding and an inability to father a child (infertility). The features of this disorder often develop during a person's twenties or thirties, although they can occur at any age. The severity of the condition varies widely among affected people, even among members of the same family. There are two major types of myotonic dystrophy: type 1 and type 2. Their signs and symptoms overlap, although type 2 tends to be milder than type 1. The muscle weakness associated with type 1 particularly affects the lower legs, hands, neck, and face. Muscle weakness in type 2 primarily involves the muscles of the neck, shoulders, elbows, and hips. The two types of myotonic dystrophy are caused by mutations in different genes. A variation of type 1 myotonic dystrophy, called congenital myotonic dystrophy, is apparent at birth. Characteristic features include weak muscle tone (hypotonia), an inward- and upward-turning foot (clubfoot), breathing problems, delayed development, and intellectual disability. Some of these health problems can be life-threatening.  http://ghr.nlm.nih.gov/condition/myotonic-dystrophy

Clinical features

Cryptorchidism
MedGen UID:
504309
Concept ID:
CN000029
Finding
Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the testis.
Testicular atrophy
MedGen UID:
504310
Concept ID:
CN000030
Finding
Wasting (atrophy) of the testicle (the male gonad) manifested by a decrease in size and potentially by a loss of fertility.
Hypogonadism
MedGen UID:
504359
Concept ID:
CN000131
Finding
A decreased functionality of the gonad.
Abnormality of the upper urinary tract
MedGen UID:
451223
Concept ID:
CN116668
Finding
An abnormality of the upper urinary tract.
Mask-like facies
MedGen UID:
140860
Concept ID:
C0424448
Finding
Facial diplegia
MedGen UID:
322796
Concept ID:
C1836003
Finding
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Non-midline cleft lip
MedGen UID:
451693
Concept ID:
CN117231
Finding
Clefting of the upper lip affecting the lateral portions of the upper lip rather than the midline/median region.
Strabismus
MedGen UID:
21337
Concept ID:
C0038379
Disease or Syndrome
Strabismus is the intermittent or constant misalignment of an eye so that its line of vision is not pointed at the same object as the other eye. Strabismus is caused by an imbalance in the extraocular muscles which control the positioning of the eyes. Strabismus is normal in newborns but should resolve by the time the baby is 6 months old. In older children with strabismus, the brain may learn to ignore the input from one eye, and this may lead to amblyopia, a potentially permanent decrease in vision in that eye if not corrected.
Cataract
MedGen UID:
368085
Concept ID:
C1962983
Finding
Intellectual disability, severe
MedGen UID:
48638
Concept ID:
C0036857
Mental or Behavioral Dysfunction
IQ 20-34.
Hypertonia
MedGen UID:
115988
Concept ID:
C0235396
Finding
Obsessive-compulsive trait
MedGen UID:
322417
Concept ID:
C1834433
Finding
Facial diplegia
MedGen UID:
322796
Concept ID:
C1836003
Finding
Intellectual disability, progressive
MedGen UID:
337397
Concept ID:
C1846149
Finding
Dysphagia
MedGen UID:
342867
Concept ID:
C1853381
Finding
Cognitive impairment
MedGen UID:
383844
Concept ID:
C1856145
Finding
Hydrocephalus
MedGen UID:
369747
Concept ID:
C1963137
Finding
Cerebral atrophy
MedGen UID:
505074
Concept ID:
CN001862
Finding
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Excessive daytime sleepiness
MedGen UID:
505150
Concept ID:
CN001985
Finding
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Hypogonadism
MedGen UID:
504359
Concept ID:
CN000131
Finding
A decreased functionality of the gonad.
Abnormality of the endocrine system
MedGen UID:
427839
Concept ID:
CN000765
Finding
Ab abnormality of the endocrine system.
Abnormality of the hip bone
MedGen UID:
425136
Concept ID:
CN002954
Finding
An abnormality of the hip bone.
Decreased fetal movement
MedGen UID:
68618
Concept ID:
C0235659
Finding
Polyhydramnios
MedGen UID:
504854
Concept ID:
CN001423
Finding
The presence of excess amniotic fluid in the uterus during pregnancy.
Dysphagia
MedGen UID:
342867
Concept ID:
C1853381
Finding
Feeding difficulties in infancy
MedGen UID:
436211
Concept ID:
C2674608
Finding
Cholelithiasis
MedGen UID:
504715
Concept ID:
CN001014
Finding
Hard, pebble-like deposits that form within the gallbladder.
Hernia of the abdominal wall
MedGen UID:
428061
Concept ID:
CN003802
Finding
The presence of a hernia in the abdominal wall.
Frontal balding
MedGen UID:
355251
Concept ID:
C1864584
Finding
Abnormal hair quantity
MedGen UID:
489172
Concept ID:
CN167090
Finding
An abnormal amount of hair.
Cardiac arrhythmia
MedGen UID:
2039
Concept ID:
C0003811
Pathologic Function
An arrhythmia is a problem with the rate or rhythm of your heartbeat. It means that your heart beats too quickly, too slowly, or with an irregular pattern. When the heart beats faster than normal, it is called tachycardia. When the heart beats too slowly, it is called bradycardia. The most common type of arrhythmia is atrial fibrillation, which causes an irregular and fast heart beat. Many factors can affect your heart's rhythm, such as having had a heart attack, smoking, congenital heart defects, and stress. Some substances or medicines may also cause arrhythmias. . Symptoms of arrhythmias include: -Fast or slow heart beat. -Skipping beats. -Lightheadedness or dizziness. -Chest pain. -Shortness of breath . -Sweating . Your doctor can run tests to find out if you have an arrhythmia. Treatment to restore a normal heart rhythm may include medicines, an implantable cardioverter-defibrillator (ICD) or pacemaker, or sometimes surgery. . NIH: National Heart, Lung, and Blood Institute.
Atrial fibrillation
MedGen UID:
368090
Concept ID:
C1963067
Finding
Atrial flutter
MedGen UID:
368091
Concept ID:
C1963068
Finding
First degree atrioventricular block
MedGen UID:
776562
Concept ID:
C2108089
Finding
Malformation of the heart and great vessels
MedGen UID:
428300
Concept ID:
CN002327
Finding
Congenital malformation of the heart or great vessels (i.e., the large blood vesslesentering and leaving the heart: aorta, the pulmonary arteries and veins, and the superior and inferior vena cava).
Respiratory insufficiency
MedGen UID:
155440
Concept ID:
C0748358
Finding
Respiratory distress
MedGen UID:
505100
Concept ID:
CN001899
Finding
Myotonia
MedGen UID:
10238
Concept ID:
C0027125
Finding
Prolonged failure of muscle relaxation after contraction. This may occur after voluntary contractions, muscle percussion, or electrical stimulation of the muscle. Myotonia is a characteristic feature of MYOTONIC DISORDERS.
Hypertonia
MedGen UID:
115988
Concept ID:
C0235396
Finding
EMG abnormality
MedGen UID:
99199
Concept ID:
C0476403
Finding
Facial diplegia
MedGen UID:
322796
Concept ID:
C1836003
Finding
Muscular hypotonia
MedGen UID:
504768
Concept ID:
CN001147
Finding
Muscular hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle), often involving reduced muscle strength. Hypotonia is characterized by a diminished resistance to passive stretching.
Skeletal muscle atrophy
MedGen UID:
505481
Concept ID:
CN002890
Finding
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Hernia of the abdominal wall
MedGen UID:
428061
Concept ID:
CN003802
Finding
The presence of a hernia in the abdominal wall.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews
  • CROGSteinert myotonic dystrophy syndrome

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