OBJECTIVETo observe trinucleotide repeat number, (CTG)n in the 3'-untranslated region of the myotonic protein kinase (MTPK) gene in a clinically suspected woman with myotonic dystrophy (DM) family history and her abortus, in order to confirm the necessity of exerting antenatal examination in patients or suspected individuals with DM family history.

METHODSLong Expand Template polymerase chain reaction (PCR) system was used to analyze CTG trinucleotide repeat numbers located in the 3' untranslated region of MTPK on chromosome 19q13.2-3 in both peripheral white cells and muscles of the suspected mother and the other two DM patients in the family. The tissues of her abortus and blood of a health woman were detected, too.

RESULTSCTG repeats in both peripheral white cells and muscles of the suspected mother and the tissue of abortus were higher than normal range of CTG repeat number. There is no significant difference between blood and muscle samples. High CTG repeats were detected in blood and muscles of the typical DM members in the family, but in the blood sample of control, CTG repeats is normal.

CONCLUSIONCTG trinucleotide analyses and antenatal examination should be done in pregnant with a DM family history, in order to reduce the birth rate of DM offspring.

Adult ; DNA ; analysis ; Female ; Fetus ; metabolism ; Humans ; Myotonic Dystrophy ; diagnosis ; genetics ; Prenatal Diagnosis ; Trinucleotide Repeats

OBJECTIVE: To analyze the clinical, familial and hereditary features of myotonic dystrophy to improve the knowledge and provide molecule evidence for gene diagnosis and prenatal diagnosis of myotonic dystrophy or dystrophia myotonia (DM) families. METHODS: Clinical data of 2 DM families were collected based on the probands. The number of trinucleotide CTG repeat in the 3' untranslated region of myotonic dystrophy protein kinase (DMPK) gene on chromosome 19 was determined by DNA sequence and repeat fragment. RESULTS: Except for 1 subclinical patient, another 5 patients progressed slowly with the features of myotonic muscular weakness and atrophy. One patient had hatchet face, 1 had cataract and diabetes mellitus, and the other 3 were bald. Electromyologram showed 3 patients had myotonic discharge and myopathic abnormalities. The number of trinucleotide CTG repeat in the 3' untranslated region of DMPK gene of 5 patients exceeded 50. CONCLUSION DM can be anticipated. Gene analysis can verify the disease and identify subclinical patients. It helps to prevent the DM births by hereditary consultation performing prenatal diagnosis.
Adolescent ; Adult ; Female ; Humans ; Male ; Myotonic Dystrophy ; diagnosis ; genetics ; Myotonin-Protein Kinase ; Pedigree ; Polymerase Chain Reaction ; methods ; Protein-Serine-Threonine Kinases ; genetics ; Trinucleotide Repeats

BACKGROUNDMyotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disease caused by abnormal expansion of cytosine-thymine-guanine (CTG) repeats in the myotonic dystrophy protein kinase gene. The clinical manifestations of DM1 are multisystemic and highly variable, and the unstable nature of CTG expansion causes wide genotypic and phenotypic presentations, which make molecular methods essential for the diagnosis. So far, very few studies about molecular diagnosis in Chinese patients with DM1 have been reported. Therefore, we carried out a study using two different methods in molecular diagnosis to verify the validity in detecting CTG expansion in Chinese patients showing DM signs.

METHODSA total of 97 Chinese individuals were referred for molecular diagnosis of DM1 using conventional polymerase chain reaction (PCR) accompanied by Southern blotting and triplet primed PCR (TP-PCR). We evaluated the sensitivity and limitation of each method using percentage.

RESULTSBy conventional PCR 65 samples showed only one fragment corresponding to the normal allele and 62 out of them were correctly diagnosed as DM1 by TP-PCR and three homologous non-DM1 samples were ruled out; Southern blotting analysis successfully made 13 out of 16 correct diagnoses with a more sensitivity using α-(32)P-labeled probes than dig-labeled probes.

CONCLUSIONMolecular analysis is necessary for the diagnosis of DM1 and TP-PCR is a reliable, sensitive, and easily performed method in molecular diagnosis which is worthy to be popularized.

Adult ; Aged ; Blotting, Southern ; Female ; Humans ; Male ; Middle Aged ; Molecular Diagnostic Techniques ; methods ; Myotonic Dystrophy ; diagnosis ; genetics ; Polymerase Chain Reaction ; Sensitivity and Specificity ; Young Adult

Congenital myotonic dystrophy type 1 (DM1) presents severe generalized weakness, hypotonia, and respiratory compromise after delivery with high mortality and poor prognosis. We presented a congenital DM1 of premature twins in the 30th week of gestation. These twins were conceived by in vitro fertilization (IVF). Both babies presented apnea and hypotonia and had characteristic facial appearance. They were diagnosed DM1 by genetic method. They were complicated by chylothorax and expired at 100 and 215 days of age, respectively. Mother was diagnosed DM1 during the evaluation of babies. This is the first report on congenital DM1 which accompanied the chylothorax. More investigation on the association with chylothorax and congenital DM1 is recommended. With a case of severe neonatal hypotonia, congenital DM1 should be differentiated in any gestational age. Finally, since DM1 is a cause of infertility, we should consider DM1 in infertility clinic with detailed history and physical examination.
Adult ; Apnea/etiology ; Blotting, Southern ; Chylothorax/complications ; Female ; Fertilization in Vitro ; Humans ; Infant, Newborn ; Infant, Premature ; Microsatellite Repeats/genetics ; Muscle Hypotonia/etiology ; Myotonic Dystrophy/complications/*diagnosis/radiography ; Twins

OBJECTIVETo investigate a patient featuring a complex neuromuscular disease phenotype.

METHODSA comprehensive analysis integrating clinical investigation, electrophysiological testing, pathological analysis and mutation screening was carried out.

RESULTSThe patient has presented clinical and pathological manifestations mimicking Duchenne muscular dystrophy. However, genetic analysis has identified no deletion in 21 exons of Dystrophin gene, no pathologic expansion of CTG repeats in DMPK gene or CCTG repeats in ZFN9 gene. Instead, a homozygous deletion of exons 7 and 8 in SMN gene was discovered.

CONCLUSIONA rare case of spinal muscular atrophy (SMA) was verified by genetic diagnosis. SMA is a group of neuromuscular disorders with great phenotypic heterogeneity and sometimes cannot be diagnosed by clinical manifestations, electrophysiological and pathological changes alone. Genetic diagnosis has become indispensable for accurate diagnosis for patients suspected to have the disease.

Adult ; Diagnosis, Differential ; Humans ; Male ; Muscular Atrophy, Spinal ; diagnosis ; genetics ; pathology ; Myotonic Dystrophy ; diagnosis ; genetics ; pathology ; Myotonin-Protein Kinase ; Phenotype ; Protein-Serine-Threonine Kinases ; genetics ; SMN Complex Proteins ; genetics ; Young Adult

Type 1 myotonic dystrophy (DM1) is an autosomal-dominant inherited disorder with a multisystem involvement, caused by an abnormal expansion of the CTG sequence of the dystrophic myotonia protein kinase (DMPK) gene. DM1 is a variable multisystem disorder with muscular and nonmuscular abnormalities. Increasingly, endocrine abnormalities, such as gonadal, pancreatic, and adrenal dysfunction are being reported. But, Electrolytes imbalance is a very rare condition in patients with DM1 yet. Herein we present a 42-yr-old Korean male of DM1 with abnormally elevated serum sodium and potassium. The patient had minimum volume of maximally concentrated urine without water loss. It was only cured by normal saline hydration. The cause of hypernatremia was considered by primary hypodipsia. Hyperkalemic conditions such as renal failure, pseudohyperkalemia, cortisol deficiency and hyperkalemic periodic paralysis were excluded. Further endocrine evaluation suggested selective hyperreninemic hypoaldosteronism as a cause of hyperkalemia.
Adult ; Humans ; Hyperkalemia/complications/*diagnosis ; Hypernatremia/complications/*diagnosis ; Hypoaldosteronism/complications/diagnosis ; Kidney Concentrating Ability ; Male ; Myotonic Dystrophy/complications/*diagnosis/*genetics ; Potassium/blood ; Protein-Serine-Threonine Kinases/*genetics ; Sodium/blood

Congenital myotonic dystrophy (CMD) is an inherited neuromuscular disorder with cardiac rhythm abnormalities that may occur as a child grows. No report has described complete atrioventricular (AV) block detected in a neonate with CMD. We report a floppy infant of 31(+4) weeks gestation with complete AV block at birth, who was diagnosed with CMD by Southern analysis. She recovered from complete AV block 32 hr after temporary transcutaneous pacing was applied. To the best our knowledge, this is the first recorded case of a complete AV block accompanied by CMD during the neonatal period. When a newborn has a complete AV block, the physician should consider the possibility of the CMD and conduct a careful physical examination.
3' Untranslated Regions ; Atrioventricular Block/complications/*diagnosis ; Blood Gas Monitoring, Transcutaneous ; Chromosomes, Human, Pair 9 ; Electrocardiography ; Female ; Humans ; Infant, Newborn ; Myotonic Dystrophy/complications/*diagnosis/genetics ; Myotonin-Protein Kinase/genetics ; Trinucleotide Repeats

BACKGROUND: Myotonic dystrophy type 1 (DM1) is an autosomal-dominant muscular dystrophy caused by expansion of cytosine-thymine-guanine (CTG) trinucleotide repeats in the myotonic dystrophy protein kinase (DMPK) gene. The clinical features of DM1 are multisystemic and highly variable, and the unstable nature of CTG expansion causes wide genotypic and phenotypic presentations. The aim of this study was to characterize the molecular and clinical spectra of DM1 in Koreans. METHODS: The CTG repeats of 283 Korean individuals were tested by PCR fragment analysis and Southern blot. The following characteristics were assessed retrospectively: spectrum of CTG expansions, clinical findings, genotype-phenotype correlation, anticipation, and genetic instability. RESULTS: One-hundred twenty-four patients were confirmed as DM1 by molecular tests, and the CTG expansions ranged from 50 to 2,770 repeats (median 480 repeats). The most frequent clinical features were myotonia, muscular weakness, and family history. Patients with muscular weakness or dysfunction of the central nervous system harbored larger CTG expansions than those without each symptom (P<0.05). The age of onset was inversely correlated with the size of the CTG expansion (gamma=-0.422, P<0.001). The instability of CTG expansion representing as the maximum difference between sibships was observed from 50 to 700 repeats in nine families. Clinical anticipation and the increase in CTG repeat were significantly higher in maternally transmitted alleles (P=0.002). CONCLUSIONS: Molecular genetic tests are not only essential for diagnosis, but also helpful for suggesting the spectrum and relationship between genotype and phenotype in Korean DM1 patients.
Blotting, Southern ; Data Interpretation, Statistical ; Female ; Genotype ; Humans ; Korea ; Male ; Myotonic Dystrophy/*diagnosis/*genetics ; Pedigree ; Phenotype ; Polymerase Chain Reaction ; Protein-Serine-Threonine Kinases/genetics ; Retrospective Studies ; Trinucleotide Repeat Expansion/genetics