Project description:ObjectivePatients with congenital myotonic dystrophy (CDM) tend to be born preterm. Although the CDM severity generally depends on the CTG repeat length, prematurity may also affect the prognosis in patients with CDM. Given that preterm birth is expected to increase the risk of CDM in newborns, we investigated the outcomes of newborns with CDM according to gestational age to assess prematurity and the CTG repeat length for predicting prognosis.ResultsWe assessed the outcomes of 54 infants with CDM using data collected from our hospitals and previously published studies. The patients were divided into mild and severe groups based on clinical outcomes. Logistic regression analysis was performed to estimate odds ratios (ORs) for CDM prognosis according to gestational age and the CTG repeat length and to construct a predictive model. Logistic regression analysis showed both the CTG repeat and gestational age were significantly associated with severe outcomes in patients with CDM (OR: 32.27, 95% CI 3.45-300.7; p = 0.002 and OR: 0.73, 95% CI 0.58-0.93; p = 0.0094, respectively). This predictive model for CDM prognosis exhibited good sensitivity (63%) and specificity (86%). Both prematurity and the CTG repeat length were significantly associated with the CDM severity.
Project description:Myotonic dystrophy type 1 (DM1) is a complex neuromuscular disease characterized by skeletal muscle wasting, weakness, and myotonia. DM1 is caused by the accumulation of CUG repeats, which alter the biological activities of RNA-binding proteins, including CUG-binding protein 1 (CUGBP1). CUGBP1 is an important skeletal muscle translational regulator that is activated by cyclin D3-dependent kinase 4 (CDK4). Here we show that mutant CUG repeats suppress Cdk4 signaling by increasing the stability and activity of glycogen synthase kinase 3β (GSK3β). Using a mouse model of DM1 (HSA(LR)), we found that CUG repeats in the 3' untranslated region (UTR) of human skeletal actin increase active GSK3β in skeletal muscle of mice, prior to the development of skeletal muscle weakness. Inhibition of GSK3β in both DM1 cell culture and mouse models corrected cyclin D3 levels and reduced muscle weakness and myotonia in DM1 mice. Our data predict that compounds normalizing GSK3β activity might be beneficial for improvement of muscle function in patients with DM1.
Project description:Myotonic dystrophy types 1 (DM1) and 2 (DM2) are dominantly inherited neuromuscular disorders caused by a toxic gain of function of expanded CUG and CCUG repeats, respectively. Although both disorders are clinically similar, congenital myotonic dystrophy (CDM), a severe DM form, is found only in DM1. CDM is also characterized by muscle fiber immaturity not observed in adult DM, suggesting specific pathological mechanisms. Here, we revealed upregulation of the interleukin-6 (IL-6) myokine signaling pathway in CDM muscles. We also found a correlation between muscle immaturity and not only IL-6 expression but also expanded CTG repeat length and CpG methylation status upstream of the repeats. Aberrant CpG methylation was associated with transcriptional dysregulation at the repeat locus, increasing the toxic RNA burden that upregulates IL-6. Because the IL-6 pathway is involved in myocyte maturation and muscle atrophy, our results indicate that enhanced RNA toxicity contributes to severe CDM phenotypes through aberrant IL-6 signaling.
Project description:Congenital myotonic dystrophy (CDM) is the most severe form of myotonic dystrophy type-1 (DM1). In adult DM1, dysregulation of alternative splicing of many transcripts results in the disease pathology. In CDM, the degree of aberrant splicing is not known, nor is it understood which transcripts are altered. Muscle biopsies were obtained from children with CDM, adults with DM1, healthy adult controls, and pathologically normal pediatric muscle. RNA was isolated and paired-end RNA-Seq was performed. Analysis used MAJIQ to generate percent spliced in (PSI) values. Sample sets were analyzed with Weighted Gene Co-expression Network Analysis (WGCNA) to identify splicing patterns. 11 muscle biopsies from children with CDM (age 2 month-16 years), 9 pediatric controls (age 1 month-13 years), 16 adult DM1 patients (ages 29-57), and 6 adult healthy controls (ages 19-28) were used for analysis. MAJIQ identified 2266 splicing events with adequate read depth and a PSI>0.15. WGCNA identified 4 patterns of splicing. The majority of the splicing events were the same in cases of CDM and DM1, while a subset of splicing changes were unique to CDM, many (e.g., PALLD) specific to development. The relative expression of RNA splicing factors with age may account for differences in the splicing patterns in CDM and DM1. Children with CDM have the RNA splicing events previously identified in adults with DM1, despite a divergent phenotype. There are also a minority of splicing events that are specific to CDM, largely related to transcripts regulating development.
Project description:Abstract BACKGROUND: Congenital Myotonic Dystrophy (CDM) is the harshest form of Myotonic Dystrophy type 1 (DM1,OMIM #160900). The mode of inheritance is autosomal dominant, and results from a microsatellite expansion in DMPK with an incidence of 2.1:1000,000 live births in Canada. The principal clinical signs during the neonatal period are myopathic facies, hypotonia and weakness resulting in such features as talipes equinovarus, nutritional, cardiac and respiratory problems. OBJECTIVES: To describe the main findings of CDM in the perinatal period. DESIGN/METHODS: A five year prospective cohort study from 2005 to 2010 of eligible incident cases of CDM was performed via the Canadian Pediatric Surveillance Program (CPSP). Reporting physicians completed a questionnaire with the medical history at birth and during the perinatal period. Our patients met the CDM criteria proposed by Campbell et al. (2013): 1) CDM symptoms with hospitalization greater of 72 hours; and 2) CTGrs above 200. RESULTS: We obtained 43 questionnaires, 22 female and 21 male (F:M ratio of 1.04:1). Average CTG repeat size (CGTrs) was 795.67 (250-2300). The main complication during the prenatal period was polyhydramnios (n=20). The majority of the patients (n=27) had full term pregnancy and with normal birth weight (n=25). Average Apgar was 4 at 1 (range 1-9), and 6 for 5 and 10. Intubation was required in 29/43 of the cases, with an average hospital stay of 43.5 days. Nutritional support (ie ng feeds) was required in 34/43, and it was longer than 14 days in 21 patients. Nine patients died, 6 of them due to respiratory failure. Four deaths were withdrawal of life support. CONCLUSION: The respiratory difficulties are well described as the principal complication in CDM (Ho et al. [2015]), but we found that the necessity of multiple nutritional interventions was the most frequent neonatal complication (79%), respiratory complications remains as the principal cause of death (66.6%). Zaki et al. (2010) describes a cohort with a 100% frequency of polyhydramnios, differing on ours where it is 46.5%. We conclude that CDM is not always evident prenatally by polyhydramnios, IUGR or preterm delivery. Nutritional and respiratory assessments should be prioritized, and nutritional interventions may extend for long periods of time. Despite high respiratory and feeding support needs, the majority of patients improved over time. Hence the importance of prenatal counseling and preparation for the complications in the neonatal period.
Project description:Although the conventional prevalence of myotonic dystrophy is 1:8,000, the prevalence in Korean population was recently reported as 1:1,245. With higher domestic result than expected, we aimed to investigate the clinical characteristics of pregnancies complicated by congenital myotonic dystrophy in our institution.We have reviewed 11 paired cases of neonates diagnosed with congenital myotonic dystrophy and their mothers between July 2004 and May 2014, with clinical features including maternal history of infertility, prenatal ultrasonographic findings, and neonatal outcomes. Cytosine-thymine-guanine (CTG) repeat expansion in the myotonic dystrophy protein kinase gene of both neonates and their mothers was also examined.None of mother was aware of their myotonic dystrophy traits before pregnancy. History of infertility followed by assisted reproductive technology accounted for 57.1% (4/7). Distinctive prenatal ultrasonographic finding was severe idiopathic polyhydramnios (66.7%, 4/6) with median amniotic fluid index of 43 (range, 37 to 66). In 37.5% (3/8) cases, decreased fetal movement was evident during prenatal ultrasound examination. For neonatal outcomes, more than half (6/11) were complicated with preterm birth and the proportion of 1-minute Apgar score <4 and 5-minute Apgar score <7 was 44.4% (4/9) and 66.7% (6/9), respectively. Most of neonates were admitted to the neonatal intensive care unit (9/10) because of hypotonia with respiratory problems and there was one infant death. Median number of cytosine-thymine-guanine repeats in mothers and neonates was 400 (range, 166 to 1,000) and 1,300 (range, 700 to 2,000), respectively.Our data suggest that severe idiopathic polyhydramnios with decreased fetal movement in pregnant women, especially with a history of infertility, requires differential diagnosis of congenital myotonic dystrophy.
Project description:The congenital form of myotonic dystrophy type 1 (cDM) is caused by the large-scale expansion of a (CTG•CAG)n repeat in DMPK and DM1-AS. The production of toxic transcripts with long trinucleotide tracts from these genes results in impairment of the myogenic differentiation capacity as cDM's most prominent morpho-phenotypic hallmark. In the current in vitro study, we compared the early differentiation programs of isogenic cDM myoblasts with and without a (CTG)2600 repeat obtained by gene editing. We found that excision of the repeat restored the ability of cDM myoblasts to engage in myogenic fusion, preventing the ensuing myotubes from remaining immature. Although the cDM-typical epigenetic status of the DM1 locus and the expression of genes therein were not altered upon removal of the repeat, analyses at the transcriptome and proteome level revealed that early abnormalities in the temporal expression of differentiation regulators, myogenic progression markers, and alternative splicing patterns before and immediately after the onset of differentiation became normalized. Our observation that molecular and cellular features of cDM are reversible in vitro and can be corrected by repeat-directed genome editing in muscle progenitors, when already committed and poised for myogenic differentiation, is important information for the future development of gene therapy for different forms of myotonic dystrophy type 1 (DM1).
Project description:INTRODUCTION:Herein we present an exploratory study of orofacial function in children with congenital myotonic dystrophy (CDM) vs. healthy controls. METHODS:We evaluated 41 children with CDM and 29 healthy controls for speech and swallow function and for lingual and labial strength. RESULTS:The Iowa Oral Performance Instrument (IOPI), measuring tongue strength, and a lip force meter (LFM), measuring lip strength, had excellent interrater reliability with intraclass correlation coefficients (ICCs) of 0.75 (n?=?19, P?<?0.001) and 0.96 (n?=?20, P?<?0.001), respectively. Mean overall lingual strength was 3.5-fold less and labial strength was about 7-fold less in CDM patients than in healthy controls. Eighteen of 24 children with CDM demonstrated dysarthria and an additional 11 participants were nonverbal. Dysarthria correlated moderately with lingual strength, age, and dysphagia. Strength measures correlated moderately with dysphagia. DISCUSSION:Children with CDM have impaired orofacial functioning that affects communication and swallowing. Reliability of strength measures may be useful for future therapeutic trials. Muscle Nerve 58: 413-417, 2018.
Project description:Profiling the genomic profiles of mental retardation patients. 13 mental retardation patients were selected for detection of genomic aberrations.
Project description:INTRODUCTION:Congenital myotonic dystrophy (CDM) occurs when symptoms of myotonic dystrophy present at birth. In this study we evaluated the relationship between physical function, muscle mass, and age to provide an assessment of the disease and help prepare for therapeutic trials. METHODS:CDM participants performed timed functional tests (TFTs), the first 2 minutes of 6-minute walk tests (2/6MWTs), and myometry tests, and also performed dual-energy X-ray absorption (DEXA) scans. Healthy controls (HCs) performed TFTs, 6MWTs, and myometry. RESULTS:Thirty-seven children with CDM and 27 HCs (age range 3-13 years) participated in the study. There were significant differences in the 10-meter walk (11.3 seconds in CDM vs. 6.8 seconds in HC) and 2MWT (91 meters in CDM vs. 193 meters in HCs). DEXA lean mass of the right arm correlated with grip strength (r?=?0.91), and lean mass of the right leg correlated with 6MWT (r?=?0.62). CONCLUSION:Children with CDM have significant limitations in strength and mobility. The tests performed were reliable, and lean muscle mass may serve as a useful biomarker. Muscle Nerve 56: 224-229, 2017.