• Journal of Interdisciplinary Genomics
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• v.3 no.2
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• pp.25-29
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• 2021

Myotonic muscular dystrophy is a disease characterized by progressive muscle weakness with myotonia and multiorgan involvement. Two subtypes have been recognized; each subtype is caused by nucleotide repeat expansion. So far, there has been no cure for myotonic muscular dystrophy. In this article, we introduce ongoing clinical trials for new drugs to modify disease course by correcting genetic derangement or its downstream in myotonic dystrophy type 1.

• Journal of Genetic Medicine
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• v.13 no.2
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• pp.105-110
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• 2016

Congenital myotonic dystrophy (CMD) which is transmitted in an autosomal-dominant manner, can also be observed in newborns born to asymptomatic parents who have a myotonic dystrophy type 1 or premutation allele, especially from the mother. A mother with myotonic dystrophy could be subfertile and the pregnancy could be complicated with the risk of a preterm birth. Newborns with CMD may demonstrate symptoms such as hypotonia and poor motor activity, as well as respiratory and feeding difficulties. Additionally, CMD has a high mortality rate at birth. Detection of the signs and symptoms during pregnancy is helpful for a prenatal diagnosis of CMD in cases where the family history is not known.

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.48-50
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• 2011

Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disorder caused by the expansion of cytosine-thymine-guanine (CTG) repeats in the myotonic dystrophy protein kinase (DMPK) gene. Some literatures indicated that DM1 had incidental CNS lesions such as white matter lesions and diffuse gray matter atrophy. We report a patient with DM1 whose brain magnetic resonance image (MRI) showed multifocal hyperintense lesions and cystic lesion on both frontotemporoparietal lobes.

• Annals of Clinical Neurophysiology
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• v.6 no.1
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• pp.61-63
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• 2004

The copy numbers of the CTG repeats are known to relate to the severity of clinical symptoms for myotonic dystrophy. The positive correlation between clinical manifestations and CTG repeat size has been demonstrated previously. A genetically confirmed myotonic dystrophy patient with 90 CTG repeat number had more severe clinical manifestation than brother with 120 CTG repeats, in adulthood.

• Journal of Genetic Medicine
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• v.1 no.1
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• pp.23-26
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• 1997

Myotonic dystrophy (DM) is caused by the expansion of CTG trinucleotide repeat near the 3' end of the gene encoding for a member of protein kinase gene family (DMPK). The normal range of the CTG repeat was determined in 178 normal individuals (141 unrelated individuals and 37 of 9 families) by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis and silver staining method. And the expansion of the CTG repeats in a DM family was analyzed with Southern analysis. In normal population, the range of CTG repeat is between 5 and 34 and 19 different alleles were observed in that range, and $(CTG)_{11-14}$ alleles were predominant. 4 members of an affected family showed the 0.5-2.0 kb size expansion of CTG repeats. In this study we could predict the incidence of DM in Korea as 1 in 20,000 and we could establish the diagnostic procedure for myotonic dystrophy.

• Genomics & Informatics
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• v.7 no.4
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• pp.181-186
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• 2009

Myotonic dystrophy type 1 (DM1), which is a dominantly inherited neurodegenerative disorder, results from a CTG trinucleotide repeat expansion in the 3'-untranslated region (3'-UTR) of the myotonic dystrophy protein kinase (DMPK) gene. Retention of mutant DMPK (mDMPK) transcripts in the nuclei of affected cells has been known to be the main cause of pathogenesis of the disease. Thus, reducing the RNA toxicity through elimination of the mutant RNA has been suggested as one therapeutic strategy against DM1. In this study, we suggested RNA replacement with a trans -splicing ribozyme as an alternate genetic therapeutic approach for amelioration of DM1. To this end, we identified the regions of mDMPK 3'-UTR RNA that were accessible to ribozymes by using an RNA mapping strategy based on a trans-splicing ribozyme library. We found that particularly accessible sites were present not only upstream but also downstream of the expanded repeat sequence. Repair or replacement of the mDMPK transcript with the specific ribozyme will be useful for DM1 treatment through reduction of toxic mutant transcripts and simultaneously restore wild-type DMPK or release nucleus-entrapped mDMPK transcripts to the cytoplasm.

• Annals of Clinical Neurophysiology
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• v.21 no.2
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• pp.94-97
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• 2019

The patients with myotonic dystrophy (MD) show ocular motor abnormalities including strabismus, vergence deficits, and inaccurate or slow saccades. Two theories have been proposed to explain the oculomotor deficits in MD. The central theory attributes the defects of eye movements of MD to the involvement of the central nervous system while the muscular theory attributes to dystrophic changes of the extraocular muscles. A 58-year-old woman with MD showed selective slowing of horizontal saccades and reduced peak velocities for both horizontal canals in head impulse tests, while smooth-pursuit eye movements and vertical head impulse responses were normal. This case suggests that the extraocular muscles-as a final common pathway of the voluntary saccade and reflexive vestibular eye movements-may better explain the defective rapid eye movements observed in MD.

• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.148-152
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• 2018

Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disorder and one of the most common muscular dystrophies affecting adults. Charcot-Marie-Tooth (CMT) disease, a common hereditary neuropathy, is characterized by atrophy of the distal limbs and peripheral nerve abnormalities. The authors report a rare case involving a 24-year-old female who was diagnosed simultaneously with both DM1 and CMT1A based on the results of a nerve conduction study (NCS). The patient, who had previously been diagnosed with DM1, was admitted for lower extremity pain. Her electrodiagnostic examination continued to reveal severe sensorimotor demyelinating polyneuropathy, and a genetic study was performed to confirm whether she had other hereditary neuropathies, except DM1, that suggested CMT1A, the most common phenotype of CMT. Severe abnormalities in an NCS in a DM1 patient may suggest the incidental coexistence of hereditary neuropathies, and further evaluations, such as genetic studies, should be performed for proper diagnosis.

• Journal of Genetic Medicine
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• v.6 no.2
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• pp.166-169
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• 2009

Not only is the concurrence of congenital myotonic dystrophy (CDM) and subgaleal hematoma (SGH) hardly ever seen but also the development of SGH during unassisted vaginal delivery is rare. We report a boy who developed huge SGH in vaginal delivery without any use of vacuum or forceps and later was diagnosed as maternally transmitted CDM. The boy had prenatal history of polyhydramnios and decreased fetal movement. Six hours after birth, severe molding of the skull associated with huge SGH on left parieto-occipital area was recognized by CT scan. At corrected age of two months, he was diagnosed as maternally transmitted CDM. This is the first report of CDM complicated by SGH occurring in non-instrumental vaginal delivery.

• Clinical and Experimental Pediatrics
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• v.62 no.2
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• pp.55-61
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• 2019

Purpose: Myotonic dystrophy, also known as dystrophia myotonica (DM), is an autosomal dominant disorder with 2 genetically distinct forms. DM type 1 (DM1) is the more common form and is caused by abnormal expansion of cytosine/thymine/guanine (CTG) repeats in the DM protein kinase (DMPK ) gene. Our study aimed to determine whether the age of onset is correlated with CTG repeat length in a population of pediatric patients with DM1. Methods: We retrospectively identified 30 pediatric patients with DM1 that underwent DMPK testing, of which the clinical data of 17 was sufficient. The cohort was divided into 2 subgroups based on the clinical phenotype (congenital-onset vs. late-onset) and number of CTG repeats (<1,000 vs. ${\geq}1,000$). Results: We found no significant difference between the age of onset and CTG repeat length in our pediatric patient population. Based on clinical subgrouping, we found that the congenital-onset subgroup was statistically different with respect to several variables, including prematurity, rate of admission to neonatal intensive care unit, need for respiratory support at birth, hypotonia, dysphagia, ventilator dependence, and functional status on last visit, compared to the late-onset subgroup. Based on genetic subgrouping, we found a single variable (poor feeding in neonate) that was significantly different in the large CTG subgroup than that in the small CTG subgroup. Conclusion: Clinical variables exhibiting statistically significant differences between the subgroups should be focused on prognosis and designing tailored management approaches for the patients; our findings will contribute to achieve this important goal for treating patients with DM1.