[Magnetic resonance imaging for the diagnosis of muscular dystrophy]. / ç£å ±æŒ¯æˆåƒåœ¨è‚Œè¥å »ä¸è‰¯ç–¾ç— è¯Šæ–­ä¸­çš„åº”ç”¨ä»·å€¼.

OBJECTIVES: To summarize the skeletal muscle magnetic resonance imaging (MRI) features of the lower limbs in common subtypes of muscular dystrophy (MD) and the experience in the application of MRI in the diagnosis of MD. METHODS: A total of 48 children with MD who were diagnosed by genetic testing were enrolled as subjects. The muscle MRI features of the lower limbs were analyzed. Cumulative fatty infiltration score was calculated for each subtype, and the correlation of cumulative fatty infiltration score with clinical indices was analyzed for Duchenne muscular dystrophy (DMD). RESULTS: DMD was characterized by the involvement of the gluteus maximus and the adductor magnus. Becker muscular dystrophy was characterized by the involvement of the vastus lateralis muscle. Limb-girdle muscular dystrophy was characterized by the involvement of the adductor magnus, the vastus intermedius, the vastus medialis, and the vastus lateralis muscle. For DMD, the cumulative fatty infiltration score of the lower limb muscles was significantly correlated with age, course of the disease, muscle strength, and motor function (P<0.05), while it was not significantly correlated with the serum creatine kinase level (P>0.05). CONCLUSIONS: Different subtypes of MD have different MRI manifestations, and MRI may help with the diagnosis and assessment of MD.

[Clinical and genetic features of limb-girdle muscular dystrophy type 1B: a case report].

This article reports a case of limb-girdle muscular dystrophy type 1B (LGMD1B) caused by a novel splicing heterozygous mutation in the LMNA gene. The proband presented with progressive aggravation of weakness in walking. There was no atrophy of the scapular muscles and the lower-extremity proximal muscles, with normal muscle tension of the extremities, grade 4 muscle strength in the upper and lower extremities, and positive Gower sign. The level of creatine kinase was 779 U/L. Muscle hematoxylin-eosin staining showed muscular dystrophy, and there was no significant reduction in the expression of Lamin A protein. Second-generation sequencing revealed a novel splicing heterozygous mutation, c.810+2T>C, in the LMNA gene, while this locus was normal in his parents. GERP++RS software predicted that the mutation site was highly conservative. Human Splice Finder and Spliceman software predicted that the mutation might be a pathogenic mutation. ExPASy software predicted that the new amino acid sequence became shorter. There were two sequences of mRNA in the patient's muscle: one was the normal sequence, which accounted for 92.2%; the other was partial intron 4 retention, which was the abnormal splice variant accounting for 7.8%. LGMD1B is a type of autosomal dominant inherited myopathy caused by a mutation in the LMNA gene located on the autosomal 1q22. This study extends the mutation spectrum of the LMNA gene and provides help to the diagnosis of LGMD1B.

Genetic analysis of the dystrophin gene in children with Duchenne and Becker muscular dystrophies.

INTRODUCTION: Duchenne and Becker muscular dystrophies (DMD and BMD) are X-linked myopathies caused by mutations of the dystrophin gene. METHODS: Multiplex ligation-dependent probe amplification (MLPA) combined with next-generation sequencing (NGS) of the exons of the dystrophin gene were performed in 92 suspected DMD/BMD patients. Patients with negative results were subjected to additional muscle diseases panel tests. RESULTS: DNA rearrangements were detected in 65 (70.65%) patients using MLPA. The deletions primarily clustered at exons 45-55, followed by exons 2-19. The duplication locations were in contrast to previous studies, which involved the 3' end of the gene. A total of 21 cases with point mutations were detected by NGS analysis. Furthermore, 6 previously unreported mutations were detected. Limb-girdle muscular dystrophy was confirmed in 2 patients after analysis with the muscle diseases panel. CONCLUSIONS: MLPA combined with NGS was effective for detection of the mutations in dystrophin gene exons. Muscle Nerve 56: 117-121, 2017.

[Infantile hypophosphatasia caused by a novel compound heterozygous mutation: a case report and pedigree analysis].

This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G>A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G>A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.

Clinical Diagnosis and Genetic Analysis of Children With Muscular Dystrophies.

More than 90% suspected muscular dystrophy (MD) can be confirmed with multiplex ligation-dependent probe amplification (MLPA) combined with targeted panel, although there are a few that cannot be identified. A total of 312 suspected MD patients were enrolled into the study. The MLPA combined with a targeted myopathy panel were performed. Patients with negative results were subjected to whole exome sequencing (WES), whole genome sequencing (WGS), and/or RNA sequencing (RNA-seq). A total of 275 cases were diagnosed as Duchenne/Becker muscular dystrophy (DMD/BMD) and 20 cases were other types of myopathy or nonmuscular diseases. Six female DMD/BMD patients suffered from varying degrees of typical DMD-like symptoms and 2 others were suspected to be gonadal mosaicism. The systematic application of WES, WGS, and/or RNA-seq highlighted the need for the detection of variants missed by the current standard diagnostic procedures. The identification of female patients and mosaic carriers was crucial to predict the risk of recurrence and allow for optimal genetic counseling.

Hyponatremia in babies: a 11-year single-center study.

Introduction: Hyponatremia is one of the most prevalent water-electrolyte disturbances encountered in clinical practice in pediatrics and can arise from various conditions. However, there are limited reports on hyponatremia in hospitalized infants. The objective of this study was to provide an overview of the incidence, etiologies, and clinical characteristics of hyponatremia in hospitalized babies (from birth to 3 years old) at a tertiary hospital. Method: Computer records of all hospitalized babies (from birth to 3 years old) with hyponatremia were extracted from the First Affiliated Hospital of Guangxi Medical University's clinical databases. Results: 801 patients from 39,019 hospital admissions were found to have hyponatremia and the overall prevalence of this condition was 2.05% in babies. Patients with hyponatremia due to aldosterone signaling abnormalities, neurological disorders, and liver diseases exhibited more severe outcomes than those with other etiologies. Conclusions: Various conditions can result in hyponatremia in hospitalized babies. Aldosterone signaling abnormalities were not that uncommon and it could lead to severe hyponatremia in babies.

Colloid solutions for fluid resuscitation in patients with sepsis: systematic review of randomized controlled trials.

BACKGROUND: Colloids are widely used for fluid resuscitation in patients with sepsis. But the optimal type of fluid remains unclear. OBJECTIVE: Our aim was to assess the effects on mortality and safety of different colloid solutions in patients with sepsis requiring volume replacement by examining direct comparisons of colloid solutions. METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, China Biological Medicine Database, VIP Chinese Journals Database, and CNKI China National Knowledge Infrastructure Whole Article Database. Randomized clinical trials comparing different colloids in septic patients needing fluid resuscitation were selected. RESULTS: Seventeen randomized clinical trials with a total 1281 participants met the inclusion criteria. Mortality was obtained in all trials. For intervention of albumin vs. hydroxyethyl starch solution (HES), the relative risk (RR) of death was 0.98 (95% confidence interval [CI] 0.74-1.30). For intervention of albumin vs. gelatin, the RR of death was 2.4 (95% CI 0.31-18.35). For intervention of gelatin vs. HES, the RR of death was 1.02 (95% CI 0.79-1.32). For the intervention of HES vs. dextran, the RR of death was 1.38 (95% CI 0.28-6.78). For the intervention of gelatin vs. dextran, RR of death was not estimable. For albumin vs. dextran, no trial was included. Four trials of intervention of albumin vs. HES recorded the change of severity score. CONCLUSIONS: There is no evidence that one colloid solution is more effective and safer than another for fluid resuscitation in sepsis. The severity score is improved in HES, but the confidence intervals are wide.

Aldosterone defects in infants and young children with hyperkalemia: A single center retrospective study.

Introduction: Hyperkalemia is a rare but severe condition in young children and usually discovered as a result of hemolysis of the blood samples taken. However, patients with defects in either aldosterone biosynthesis or function can also present with hyperkalemia- as well hyponatremia-associated, and metabolic acidosis. It is a challenge to make an accurate diagnosis of these clinical conditions. We conducted this study to investigate the clinical and genetic features of aldosterone signaling defects associated hyperkalemia in young children. Method: A retrospective review was conducted at the pediatric department of the First Affiliated Hospital of Guangxi Medical University from 2012 to 2022. Results: 47 patients with hyperkalemia were enrolled, of which 80.9% (n = 38) were diagnosed with primary hypoaldosteronism, including congenital adrenal hyperplasia due to 21-hydroxylase deficiency (n = 32), isolated hypoaldosteronism (n = 1) due to CYP11B2 gene mutation and Xp21 contiguous gene deletion syndrome (n = 1). Additionally, 4 patients were clinically-diagnosed with primary adrenal insufficiency. Nine patients were confirmed with aldosterone resistance, of which one child was diagnosed with pseudohypoaldosteronism (PHA) type 1 with a mutation in the NR3C2 gene and 3 children were identified with PHA type 2 due to novel mutations in either the CUL3 or KLHL3 genes. Five patients had PHA type 3 because of pathologies of either the urinary or intestinal tracts. Conclusions: The etiologies of infants with hyperkalemia associated with aldosterone defects were mostly due to primary hypoaldosteronism. An elevated plasma aldosterone level may be a useful biomarker for the diagnosis an aldosterone functional defect in patients presented with hyperkalemia. However, a normal plasma aldosterone level does rule out an aldosterone defect in either its biosynthesis or function, especially in young infants. Molecular genetic analyses can greatly help to clarify the complexity of disorders and can be used to confirm the diagnosis.

Detection of gonosomal mosaicism by ultra-deep sequencing and droplet digital PCR in patients with Emery-Dreifuss muscular dystrophy.

BACKGROUND: Emery-Dreifuss muscular dystrophy (EDMD2) is a rare form of muscular dystrophy that is inherited as an autosomal dominant trait. In some patients, it is inherited from parental mosaicism, and this increases the recurrence risk significantly. The presence of mosaicism is underestimated due to the limitations of genetic testing and the difficulty in obtaining samples. METHODS: A peripheral blood sample from a 9-year-old girl with EDMD2 was analyzed by enhanced whole exome sequencing (WES). Sanger sequencing in her unaffected parents and younger sister was performed for validation. In the mother, ultra-deep sequencing and droplet digital PCR (ddPCR) in multiple samples (blood, urine, saliva, oral epithelium, and nail clippings) were performed in order to identify the suspected mosaicism of the variant. RESULTS: WES revealed a heterozygous mutation (LMNA, c.1622G>A) in the proband. Sanger sequencing of the mother suggested the presence of mosaicism. The ratio of mosaic mutation was confirmed in different samples by ultra-deep sequencing and ddPCR (19.98%-28.61% and 17.94%-28.33%, respectively). This inferred that the mosaic mutation may have occurred early during embryonic development and that the mother had gonosomal mosaicism. CONCLUSION: We described a case of EDMD2 caused by maternal gonosomal mosaicism which was confirmed by using ultra-deep sequencing and ddPCR. This study illustrates the importance of a systematic and comprehensive screening of parental mosaicism with more sensitive approaches and the use of multiple tissue samples.

Novel miRNA Biomarkers for Patients With Duchenne Muscular Dystrophy.

Creatine kinase (CK) as a biomarker has long been expected to be replaced by other fluid biomarkers for Duchenne muscular dystrophy (DMD) because it is independent of disease severity. Growing evidence has demonstrated that muscle-specific microRNAs, known as myomiRs, can act as biomarkers for monitoring muscle pathology and disease severity of DMD patients. To gain insights into the relationship between serum myomiRs and clinical assessment, we measured serum levels of miR-1, miR-133a, miR-133b, miR-206, miR-208a, miR-208b, and miR-499 in 48 DMD patients by using real-time quantitative reverse transcription polymerase chain reaction. These were then compared with age, muscle strength, muscle functions, CK levels, cardiac manifestations, and mutation types (deletions, duplications, and small mutations). When compared to 53 controls, the expression levels of myomiRs were all significantly elevated (p < 0.05). The receiver operating characteristic curves of all seven myomiRs reflected marked differences between DMD patients and healthy controls (p < 0.05). We also showed that serum levels of myomiRs were positively correlated with lower limb distal muscle strength in patients of all age groups. The levels of miR-499, miR-208b, miR-133a, and miR-133b had significant negative correlations with the time to be upright from the supine position (Gowers' time) and the time taken to climb four stairs in DMD patients older than 7 years. Serum levels of miR-1, miR-133a, miR-133b, and miR-499 in patients with cardiac involvement were remarkably higher than those in non-cardiac-involved patients. There was no significant difference in levels of myomiRs between the different mutation groups. Our results indicated that serum myomiRs could be considered as novel biomarkers for monitoring pathology/pathophysiology of DMD patients. In particular, miR-499, miR-208b, miR-133a, and miR-133b might have the ability to reflect the extent of muscle impairment.

Serum irisin levels increase in girls with central precocious puberty not dependent on BMI: a pilot study.

Objective: The objective of this study is to investigate the role of serum irisin level in diagnosis of central precocious puberty (CPP) in girls and its major determinants. Methods: This study was conducted in 67 girls with CPP, 19 girls with premature thelarche (PT) and 59 normal controls. The major determinants of irisin were assessed by multivariate linear regression (MLR) analysis. Propensity score matching (PSM) analysis was performed to minimize the bias that can result from BMI. A receiver operating characteristic curve was used to obtain the optimal threshold value of irisin. Results: The girls with CPP and PT had higher irisin levels than controls (P < 0.05). The optimal cutoff value of irisin levels for predicting CPP was 91.88 ng/mL, with a sensitivity of 70.1% and a specificity of 72.9%. MLR analysis showed that BMI was a predictor of irisin (P < 0.05). Serum irisin levels remained higher in the CPP girls than the controls with adjustment for BMI (P < 0.05). Conclusions: Increased serum irisin levels with CPP suggest that irisin is involved in puberty. However, due to low sensitivity and specificity, irisin level can only be used as an auxiliary indicator rather than a single diagnostic indicator of CPP.

The role of kisspeptin and MKRN3 in the diagnosis of central precocious puberty in girls.

OBJECTIVE: To evaluate the characteristics and significance of serum kisspeptin and makorin ring finger protein 3 (MKRN3) levels for the diagnosis of central precocious puberty (CPP) in girls. METHOD: Thirty four individuals with CPP, 17 individuals with premature thelarche (PT), and 28 age-matched prepubertal girls as normal control (NC) were recruited in this case-control study. Physical measurements included BMI and tests for breast, bone, and sexual characteristics. Biochemical measurements included serum LH, FSH, estradiol, insulin-like growth factor-1, MKRN3, and kisspeptin. Blood samples were taken from individuals with CPP and PT before the gonadotrophin-releasing hormone stimulation test and at 30, 60, 90, and 120 min after injection with triptorelin. RESULTS: Serum kisspeptin levels were higher in the CPP group when compared to the NC group (P = 0.020), while serum MKRN3 levels were lower in the two groups (P = 0.028). There were no significant differences between the CPP and PT groups as well as the PT and NC groups (all, P > 0.05). The cut-off value of serum kisspeptin differentiating patients with CPP from those without CPP was 0.40 nmol/L, with 82.4% sensitivity and 57.1% specificity, while the cut-off value of serum MKRN3 was 0.33 pmol/L, with 79.4% sensitivity and 53.6% specificity. The area under the curves (AUCs) of both kisspeptin and MKRN3 for differentiating those girls with CPP from PT were less than 0.5. CONCLUSIONS: Serum levels of kisspeptin and MKRN3 may play an auxiliary role in predicting CPP. However, the two measurements were not able to differentiate girls with CPP from PT and prepubertal control. This study emphasizes the need to search for markers to simplify the accurate diagnosis of CPP in girls.

Use of RNA­sequencing to detect abnormal transcription of the collagen α­2 (VI) chain gene that can lead to Bethlem myopathy.

Bethlem myopathy (BM) is an autosomal dominant or autosomal recessive disorder and is usually associated with mutations in the collagen VI genes. In the present study, the pathogenicity of a novel splice­site mutation was explored using RNA­sequencing in a family with suspected BM, and a myopathy panel was performed in the proband. The genetic status of all family members was confirmed using Sanger sequencing. Clinical data and magnetic resonance imaging (MRI) features were also documented. In silico analysis was performed to predict the effects of the splice mutation. RNA­sequencing and reverse transcription (RT)­PCR were used to assess aberrant splicing. Immunocytochemistry was conducted to measure collagen VI protein levels within the gastrocnemius and in cultured skin fibroblasts. The results revealed that three patients in the family shared a similar classic BM presentation. MRI revealed distinct patterns of fatty infiltration in the lower extremities. A novel splicing mutation c.736­1G>C in the collagen α­2 (VI) chain (COL6A2) gene was found in all three patients. In silico analysis predicted that the mutation would destroy the normal splice acceptor site. RNA­sequencing detected two abnormal splicing variants adjacent to the mutation site, and RT­PCR confirmed the RNA­sequencing findings. Furthermore, a defect in the collagen protein within cultured fibroblasts was detected using immunocytochemistry. The mutation c.736­1G>C in the COL6A2 gene caused aberrant splicing and led to premature termination of protein translation. In conclusion, these findings may improve our knowledge of mutations of the COL6A2 gene associated with BM and demonstrated that RNA­sequencing can be a powerful tool for finding the underlying mechanism of a disease­causing mutations at a splice site.

The use of glimepiride for the treatment of neonatal diabetes mellitus caused by a novel mutation of the ABCC8 gene.

OBJECTIVES: Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes that is usually diagnosed in the first six months of life. CASE PRESENTATION: We report on a male infant with neonatal diabetes who presented with diabetic ketoacidosis at two months and 16 days. A novel homozygous missense mutation (c.259T>G) was identified in the ABCC8 gene. In this case, insulin was replaced with glimepiride at a dosage of 0.49 mg/kg/day at five months, and this achieved metabolic control and satisfactory growth as observed at follow-up. CONCLUSIONS: This report improves our understanding of the mutational spectrum of ABCC8, which is normally associated with NDM, and shows that the treatment regimen for this condition can be successfully switched from insulin therapy to the use of sulfonylurea.

Corrigendum: Serum MyomiRs as Biomarkers for Female Carriers of Duchenne/Becker Muscular Dystrophy.

[This corrects the article DOI: 10.3389/fneur.2020.563609.].

Serum MyomiRs as Biomarkers for Female Carriers of Duchenne/Becker Muscular Dystrophy.

Background: Duchenne/Becker muscular dystrophy (DMD/BMD) is an X-linked recessive lethal neuromuscular disease. MicroRNAs expressed in striated muscle, myomiRs, have been proposed as its potential biomarkers. Serum creatine kinase (CK) is commonly used as a biomarker in clinical practice, but it is not reliable. The aim of this study was to assess whether serum levels of myomiRs has diagnostic value for detection of female DMD/BMD carriers with normal or elevated CK. Methods: Thirty four female carriers and 33 age-matched healthy female controls were enrolled. Peripheral blood samples were collected and serum miRNAs were extracted for measurement of miR-1, miR-133a, miR-133b, miR-206, miR-208a, miR-208b, and miR-499 by quantitative real-time polymerase chain reaction. Results: MiR-1, miR-133a, miR-133b, miR-206, miR-208a, miR-208b, and miR-499 were upregulated in all female carriers in comparison to healthy controls. MiR-1 (Spearman's rho = +0.406, p = 0.017) was correlated with CK in the female carrier group. Receiver operating characteristic curve analysis of all seven myomiRs showed that the area under the curve (AUC) for miR-499, miR-133b, miR-1, miR-208b, and miR-133a exceeded 70.0%, and for miR-206 and miR-208a exceeded 60.0%. MiR-133b and miR-499 were significantly increased in all female carriers, even those with normal CK. AUC for the combination of all seven miRNAs was 87.2%. CK (OR 0.406, 95% CI 0.000-0.001, p < 0.0001) and miR-499 (OR 0.323, 95% CI 0.023-0.106, p = 0.003) were considered to be independent predictors for female carriers presence in the multivariable regression analysis model. Conclusions: MiR-133b and miR-499 are potentially useful biomarkers for female carriers with DMD/BMD (including those with normal CK). The combination of all seven serum miRNAs and their respective combinations with CK have better diagnostic value for female carriers than either CK or any separate miRNA.

Clinical and genetic characteristics of female dystrophinopathy carriers.

The present study aimed to determine the genetic status of manifesting carriers (MCs) of Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD) and asymptomatic carriers with a family history of DMD/BMD, and identify potential simple and reliable methods for screening dystrophinopathy carriers. Clinical data from probable carriers and MCs were collected and analyzed. MCs underwent multiplex ligation­dependent probe amplification (MLPA) for dystrophin gene exons combined with muscle disease panel test based on a next­generation sequencing (NGS) platform. In addition, the status of probable carriers was determined by MLPA or Sanger sequencing, according to the mutations of probands. A total of 154 female were enrolled, among which 78 cases were found to be carriers, including 4 MCs and 74 asymptomatic female carriers. The 4 MCs exhibited duplication mutations. Among the 74 asymptomatic carriers, 41.89% harbored deletion mutations, including 2 cases with suspected germline mosaicism and no mutation in the dystrophin gene, while 44.59% harbored point mutations in exons and only 10 cases (13.51%) carried duplication mutations. The area under the receiver operating characteristic (ROC) curve of creatine kinase (CK) was 0.822, with a sensitivity of 65.38% and specificity of 92.1%. In addition, DMD was positively correlated with the CK, alanine transaminase and aspartate transaminase levels of the carriers. MLPA for exons of the dystrophin gene, along with NGS and Sanger sequencing, was effective for the diagnosis of MCs and for determining the status of probable carriers. The ROC curve analysis also demonstrated that CK level was an excellent predictor for distinguishing DMD/BMD carriers.

Novel compound heterozygous PLEC mutations lead to early­onset limb­girdle muscular dystrophy 2Q.

Limb-girdle muscular dystrophy 2Q (LGMD2Q) is a specific mutation in the plectin (PLEC1) gene at chromosome 8q24.3. In the present study, targeted sequencing using a muscle disease gene panel was performed in a patient with muscular dystrophy. The family members were confirmed by Sanger sequencing. The PolyPhen­2, SIFT and MutationTaster tools were used to predicted the possible effect of the mutations. Immunocytochemistry was used to visualize and localize the plectin protein within the gastrocnemius. Novel compound heterozygous mutations c.5995C>T (p.Arg1999Trp) and c.9940T>A (p.Phe3314 Ile) in the PLEC gene were identified to be the genetic cause of LGMD2Q in this family. These variants were absent in 200 normal controls. Furthermore, defects in the plectin protein within the gastrocnemius were determined using immunocytochemistry. To the best of our knowledge, the present study provides the second report on plectin­associated LGMD2Q without other symptoms, although the genotype identified was novel. The missense mutations in the proband were considered to be an explanation for the symptom. These findings extend current knowledge of the mutation spectrum of the PLEC gene associated with LGMD2Q.