Elevated Serum Creatine Kinase Research Articles

Expert panel curation of 31 genes in relation to limb girdle muscular dystrophy.

Limb girdle muscular dystrophies (LGMDs) are a group of genetically heterogeneous autosomal conditions with some degree of phenotypic homogeneity. LGMD is defined as having onset >2 years of age with progressive proximal weakness, elevated serum creatine kinase levels and dystrophic features on muscle biopsy. Advances in massively parallel sequencing have led to a surge in genes linked to LGMD. The ClinGen Muscular Dystrophies and Myopathies gene curation expert panel (MDM GCEP, formerly Limb Girdle Muscular Dystrophy GCEP) convened to evaluate the strength of evidence supporting gene-disease relationships (GDR) using the ClinGen gene-disease clinical validity framework to evaluate 31 genes implicated in LGMD. The GDR was exclusively LGMD for 17 genes, whereas an additional 14 genes were related to a broader phenotype encompassing congenital weakness. Four genes (CAPN3, COL6A1, COL6A2, and COL6A3) were split into two separate disease entities, based on each displaying both dominant and recessive inheritance patterns, resulting in curation of 35 GDRs. Of these, 30 (86%) were classified as definitive, 4 (11%) as moderate, and 1 (3%) as limited. Two genes, POMGNT1 and DAG1, though definitively related to myopathy, currently have insufficient evidence to support a relationship specifically with LGMD. The expert-reviewed assertions on the clinical validity of genes implicated in LGMDs form an invaluable resource for clinicians and molecular geneticists. We encourage the global neuromuscular community to publish case-level data that help clarify disputed or novel LGMD associations.

Acute Kidney Injury in Hospitalized Patients With Exertional Rhabdomyolysis

An association between serum creatine kinase (CK) levels and the risk of kidney failure in patients with exertional rhabdomyolysis (ERM) has been suggested. However, the actual incidence of AKI in hospitalized patients with ERM along with the contributing cofactors that may increase the risk of AKI have rarely been investigated. To examine the incidence of kidney injury in hospitalized patients with ERM and to identify additional cofactors that might contribute to the development of kidney injury in patients with ERM. This retrospective cohort study was conducted in a diverse community population of patients 18 years or older with ERM who were hospitalized across Kaiser Permanente Northern California between January 1, 2009, and December 31, 2019. Patients were initially identified through electronic screening for all-cause rhabdomyolysis admissions, followed by manual medical record reviews to verify their eligibility for the study. The diagnosis of AKI and chronic kidney disease (CKD) was determined using KDIGO (Kidney Disease Improving Global Outcomes) criteria and confirmed by medical record review. Data analysis was performed from October 1, 2023, to January 31, 2024. History of strenuous physical exercise before hospitalization for ERM. Development of AKI, CKD, and compartment syndrome and number of deaths. Among 3790 patients hospitalized for rhabdomyolysis between 2009 and 2019 in Kaiser Permanente Northern California, 200 (mean [SD] age, 30.5 [8.5] years; 145 [72.5%] male) were confirmed to have ERM via medical record review. Seventeen patients (8.5%) developed AKI, none developed CKD, 1 (0.5%) developed compartment syndrome, and there were no fatalities. There was no association between serum CK levels and the risk of AKI. However, the risk of AKI was significantly higher in patients with ERM who used nonsteroidal anti-inflammatory drugs (NSAIDs) before admission (11 of 17 with AKI [64.7%] vs 40 of 183 without AKI [21.9%], P < .001) or experienced dehydration (9 of 183 without AKI [52.9%] vs 9 of 17 with AKI [4.9%], P < .001). This analysis suggests that eliminating preadmission NSAID use and dehydration could reduce the risk of potential AKI in patients with ERM by 92.6% (95% CI, 85.7%-96.1%) in this population. The findings of this cohort study of hospitalized patients with ERM suggest that serum CK elevation alone is insufficient as an indicator of AKI in patients with ERM. Concurrent risk factors, such as NSAID use or dehydration, may be associated with AKI development in patients with ERM.

Dominant stop-loss HNRNPA1 variants in juvenile-onset myopathy.

Heterogeneous nuclear ribonucleoprotein A1 is involved in nucleic acid homeostatic functions. The encoding gene HNRNPA1 has been associated with several neuromuscular disorders including an amyotrophic lateral sclerosis-like phenotype, distal hereditary motor neuropathy, multisystem proteinopathy, and various myopathies. We report two unrelated individuals with monoallelic stop loss variants affecting the same codon of HNRNPA1. Two individuals with unsolved juvenile-onset myopathy were enrolled under approved institutional protocols. Phenotype data were collected and genetic analyses were performed, including whole-exome sequencing (WES). The two probands (MNOT002-01 and K1440-01) showed a similar onset of slowly progressive extremity and facial weakness in early adolescence. K1440-01 presented with facial weakness, winged scapula, elevated serum creatine kinase (CK) levels, and mild neck weakness. MNOT002-01 also exhibited elevated CK levels along with facial weakness, cardiomyopathy, respiratory dysfunction, pectus excavatum, a mildly rigid spine, and loss of ambulation. On quadriceps muscle biopsy, K1440-01 displayed rounded myofibers, mild variation in fiber diameter, and type 2 fiber hypertrophy, while MNOT002-01 displayed rimmed vacuoles. Monoallelic stop-loss variants in HNRNPA1 were identified for both probands: c.1119A>C p.*373Tyrext*6 (K1440-01) and c.1118A>C p.*373Serext*6 (MNOT002-01) affect the same codon and are both predicted to lead to the addition of six amino acids before termination at an alternative stop codon. Both stop-loss variants in our probands are likely pathogenic. Our findings contribute to the disease characterization of pathogenic variants in HNRNPA1. This gene should be screened in clinical diagnostic testing of unsolved cases of sporadic or dominant juvenile-onset myopathy.

Feasibility of aligning creatine kinase MB activity and mass data in multicentre trials using generalized additive modelling.

Elevated serum creatine kinase isoenzyme MB (CK-MB) levels indicate myocardial ischaemia and periprocedural myocardial injury during treatment of heart diseases. We established a method to predict CK-MB mass from activity data based on a prospective pilot study in order to simplify multicentre trials. 38 elective cardiac surgery patients without acute myocardial ischaemia and terminal renal failure were recruited. CK-MB mass and activity were determined in venous blood samples drawn preoperatively, postoperatively, 6 h post-op, and 12 h post-op. Linear regression and generalized additive models (GAMs) were applied to describe the relationship of mass and activity. Influences of demographic and perioperative factors on the fit of GAMs was evaluated. The agreement of predicted and measured CK-MB masses was assessed by Bland-Altman analyses. Linear regression provided an acceptable overall fit (r2 = 0.834) but showed deviances at low CK-MB levels. GAMs did not benefit from the inclusion of age, body mass index and surgical times. The minimal adequate model predicted CK-MB masses from activities, sex and sampling time with an r2 of 0.981. Bland-Altman analyses confirmed narrow limits of agreement (spread: 8.87 µg/l) and the absence of fixed (P = 0.41) and proportional (P = 0.21) biases. GAM-based modelling of CK-MB data in a representative patient cohort allowed to predict CK-MB masses from activities, sex and sampling time. This approach simplifies the integration of study centres with incompatible CK-MB data into multicentre trials in order to facilitate inclusion of CK-MB levels in statistical models.

A case control study of the relationship between persistent serum creatine kinase elevation and polyneuropathy

Creatine kinase (CK) has been associated with neuropathy, but the mechanisms are uncertain. We hypothesized that peripheral nerve function is impaired in subjects with persistent CK elevation (hyperCKemia) compared to age- and sex matched controls in a general population. The participants were recruited from the population based Tromsø study in Norway. Neuropathy impairment score (NIS), nerve conduction studies (NCS) and electromyography (EMG) in subjects with persistent hyperCKemia (n = 113; 51 men, 62 women) and controls (n = 128; 61 men, 67 women) were performed. The hyperCKemia group had higher NIS score than the controls (p = 0.050). NCS of the tibial nerve showed decreased compound motor action potential amplitude (p < 0.001), decreased motor conduction velocity (p < 0.001) and increased F-wave latency (p = 0.044). Also, reduced sensory amplitudes of the median, ulnar, and sural nerves were found. EMG showed significantly increased average motor unit potential amplitude in all examined muscles. CK correlated positively with glycated hemoglobin and non-fasting glucose in the hyperCKemia group, although not when controlled for covariates. The length dependent polyneuropathy demonstrated in the hyperCKemia group is unexplained, but CK leakage and involvement of glucose metabolism are speculated on.

Pregabalin-induced rhabdomyolysis: a case series and literature analysis.

Pregabalin is a prescription medicine that has recently been approved for individuals who suffer from fibromyalgia, neuropathic pain, anxiety disorder, or epilepsy. Pregabalin has the side effects of dizziness, sleepiness, and angioedema. Pregabalin-induced rhabdomyolysis has been rarely reported, with only four reports to date. We report two cases of rhabdomyolysis after pregabalin treatment. A man aged older than 90 years presented with exhaustion, muscle aches, and a high serum creatine kinase concentration after taking 75 mg of pregabalin on the first day of treatment. A woman in her 90s with long-term use of pregabalin presented with considerably elevated serum creatine kinase concentrations. Both patients had a long history of taking statins. Pregabalin therapy was stopped, high-volume intravenous fluids were administered, and serum electrolytes were frequently checked. Alkalinisation was performed with excellent outcomes. The Naranjo Adverse Drug Reaction scale and previous research suggest an association between pregabalin and rhabdomyolysis. Clinicians should be alert to the possibility of rhabdomyolysis occurring with the use of pregabalin, especially when taking statins.

Immune-Mediated Necrotizing Myopathy

Immune-mediated necrotizing myopathy (IMNM) is a form of autoimmune myositis characterized by the presence of necrotic and regenerating process as a major finding in the muscle. Anti-SRP and anti-HMGCR have been identified as IMNM-specific autoantibodies. Patients with this disease often present with severe muscle weakness and markedly elevated serum creatine kinase (CK) levels. Differentiation from muscular dystrophy is challenging in certain cases. When patients meet the condition "subacute onset", "hyperCKemia over 1000 IU/L", and "clinical diagnosis of muscular dystrophy lacking molecular diagnosis", the possibility of IMNM should be considered. Autoantibody measurement, including of anti-SRP and HMGCR antibodies, is recommended. Treatment with corticosteroid in combination with immunosuppressants, intravenous immunoglobulin, and rituximab can be performed.

An Intronic Heterozygous SYNE2 Splice Site Mutation: A Rare Cause for Myalgia and hyperCKemia?

SYNE2 mutations have been associated with skeletal and cardiac muscle diseases, including Emery-Dreifuss muscular dystrophy (EDMD). Here, we present a 70-year-old male patient with muscle pain and elevated serum creatine kinase levels in whom whole-exome sequencing revealed a novel heterozygous SYNE2 splice site mutation (NM_182914.3:c.15306+2T&gt;G). This mutation is likely to result in the loss of the donor splice site in intron 82. While a diagnostic muscle biopsy showed unspecific myopathological findings, immunofluorescence analyses of skeletal muscle and dermal cells derived from the patient showed nuclear shape alterations when compared to control cells. In addition, a significantly reduced nesprin-2 giant protein localisation to the nuclear envelope was observed in patient-derived dermal fibroblasts. Our findings imply that the novel heterozygous SYNE2 mutation results in a monoallelic splicing defect of nesprin-2, thereby leading to a rare cause of myalgia and hyperCKemia.

Clinical and genetic interpretation of uncertain DMD missense variants: evidence from mRNA and protein studies

BackgroundPathogenic missense variants in the dystrophin (DMD) gene are rarely reported in dystrophinopathies. Most DMD missense variants are of uncertain significance and their pathogenicity interpretation remains complicated. We aimed to investigate whether DMD missense variants would cause aberrant splicing and re-interpret their pathogenicity based on mRNA and protein studies.MethodsNine unrelated patients who had an elevated serum creatine kinase level with or without muscle weakness were enrolled. They underwent a detailed clinical, imaging, and pathological assessment. Routine genetic testing and muscle-derived mRNA and protein studies of dystrophin and sarcoglycan genes were performed in them.ResultsThree of the 9 patients presented with a Duchenne muscular dystrophy (DMD) phenotype and the remaining 6 patients had a suspected diagnosis of Becker muscular dystrophy (BMD) or sarcoglycanopathy based on their clinical and pathological characteristics. Routine genetic testing detected only 9 predicted DMD missense variants in them, of which 6 were novel and interpreted as uncertain significance. Muscle-derived mRNA studies of sarcoglycan genes didn’t reveal any aberrant transcripts in them. Dystrophin mRNA studies confirmed that 3 predicted DMD missense variants (c.2380G > C, c.4977C > G, and c.5444A > G) were in fact splicing and frameshift variants due to aberrant splicing. The 9 DMD variants were re-interpreted as pathogenic or likely pathogenic based on mRNA and protein studies. Therefore, 3 patients with DMD splicing variants and 6 patients with confirmed DMD missense variants were diagnosed with DMD and BMD, respectively.ConclusionOur study highlights the importance of muscle biopsy and aberrant splicing for clinical and genetic interpretation of uncertain DMD missense variants.

Caregiver Burden with Duchenne and Becker Muscular Dystrophy in Japan: A Clinical Observation Study.

Objective Skeletal muscle weakness and cardiomyopathy can be seen in carriers of dystrophinopathy. Therefore, the health management of caregivers of Duchenne/Becker muscular dystrophy (DMD/BMD) patients who are themselves carriers is an important issue. However, few studies have focused on caregivers who have dystrophin mutations. Methods In this cross-sectional study conducted at five hospitals, the daily living, situation medical treatment status, genetic testing, physical assessment, care burden, and quality of life of caregivers of DMD/BMD patients were surveyed. Results The subjects were 36 main caregivers (mean age 55.7±8.4 years old), of whom 52.8% were diagnosed as carriers, 8.3% were noncarriers, and 38.9% were not confirmed. In addition, half of the caregivers were not examined regularly at medical institutions. Of all caregivers, 54.3% had muscle or cardiac symptoms, and 75% had elevated serum creatine kinase levels. The mean Zarit Caregiver Burden Interview (ZBI) total score of current caregivers was 20.9±13.1. The frequency of a ZBI total score ≥25 was significantly higher in caregivers diagnosed as carriers than in caregivers unexamined as carriers (p=0.04). The health-related quality of life score (Short Form 36; SF-36) in caregivers was slightly lower than the Japanese standard scores in the sections of physical functioning, role limitations-physical, bodily pain, and social functioning. Conclusion Some caregivers of DMD/BMD patients can themselves have muscular or cardiac symptoms and a heavy care burden. It is therefore necessary for carrier caregivers, especially women, to undergo regular health checkups and receive appropriate health management.

Nationwide survey of patients with multisystem proteinopathy in Japan.

Multisystem proteinopathy (MSP) is an inherited disorder in which protein aggregates with TAR DNA-binding protein of 43 kDa form in multiple organs. Mutations in VCP, HNRNPA2B1, HNRNPA1, SQSTM1, MATR3, and ANXA11 are causative for MSP. This study aimed to conduct a nationwide epidemiological survey based on the diagnostic criteria established by the Japan MSP study group. We conducted a nationwide epidemiological survey by administering primary and secondary questionnaires among 6235 specialists of the Japanese Society of Neurology. In the primary survey, 47 patients with MSP were identified. In the secondary survey of 27 patients, inclusion body myopathy was the most common initial symptom (74.1%), followed by motor neuron disease (11.1%), frontotemporal dementia (FTD, 7.4%), and Paget's disease of bone (PDB, 7.4%), with no cases of parkinsonism. Inclusion body myopathy occurred most frequently during the entire course of the disease (81.5%), followed by motor neuron disease (25.9%), PDB (18.5%), FTD (14.8%), and parkinsonism (3.7%). Laboratory findings showed a high frequency of elevated serum creatine kinase levels and abnormalities on needle electromyography, muscle histology, brain magnetic resonance imaging, and perfusion single-photon emission computed tomography. The low frequency of FTD and PDB may suggest that FTD and PDB may be widely underdiagnosed and undertreated in clinical practice.

Metabolic and other morbid complications in congenital generalized lipodystrophy type 4.

Morbidity and mortality rates in patients with autosomal recessive, congenital generalized lipodystrophy type 4 (CGL4), an ultra-rare disorder, remain unclear. We report on 30 females and 16 males from 10 countries with biallelic null variants in CAVIN1 gene (mean age, 12 years; range, 2 months to 41 years). Hypertriglyceridemia was seen in 79% (34/43), hepatic steatosis in 82% (27/33) but diabetes mellitus in only 21% (8/44). Myopathy with elevated serum creatine kinase levels (346-3325 IU/L) affected all of them (38/38). 39% had scoliosis (10/26) and 57% had atlantoaxial instability (8/14). Cardiac arrhythmias were detected in 57% (20/35) and 46% had ventricular tachycardia (16/35). Congenital pyloric stenosis was diagnosed in 39% (18/46), 9 had esophageal dysmotility and 19 had intestinal dysmotility. Four patients suffered from intestinal perforations. Seven patients died at mean age of 17 years (range: 2 months to 39 years). The cause of death in four patients was cardiac arrhythmia and sudden death, while others died of prematurity, gastrointestinal perforation, and infected foot ulcers leading to sepsis. Our study highlights high prevalence of myopathy, metabolic abnormalities, cardiac, and gastrointestinal problems in patients with CGL4. CGL4 patients are at high risk of early death mainly caused by cardiac arrhythmias.

Multiple Acyl-CoA Dehydrogenase Deficiency: Phenotypic and Genetic Features of a Malaysian Cohort.

Multiple acyl-CoA dehydrogenase deficiency (MADD) is an inherited disorder of fatty acid oxidation that causes lipid storage myopathy (LSM). This is the first report on MADD that describes the phenotypic and genetic features of a Malaysian cohort. Among the >2,500 patients in a local muscle biopsy database, patients with LSM were identified and their genomic DNA were extracted from muscle samples and peripheral blood. All 13 exons of the electron-transfer flavoprotein dehydrogenase gene (ETFDH) were subsequently sequenced. Fifty controls were included to determine the prevalence of identified mutations in the normal population. Fourteen (82%) of the 17 LSM patients had MADD with ETFDH mutations. Twelve (86%) were Chinese and two were Malay sisters. Other unrelated patients reported that they had no relevant family history. Nine (64%) were females. The median age at onset was 18.5 years (interquartile range=16-37 years). All 14 demonstrated proximal limb weakness, elevated serum creatine kinase levels, and myopathic changes in electromyography. Three patients experienced a metabolic crisis at their presentation. Sanger sequencing of ETFDH revealed nine different variants/mutations, one of which was novel: c.998A>G (p.Y333C) in exon 9. Notably, 12 (86%) patients, including the 2 Malay sisters, carried a common c.250G>A (p.A84T) variant, consistent with the hotspot mutation reported in southern China. All of the patients responded well to riboflavin therapy. Most of our Malaysian cohort with LSM had late-onset, riboflavin-responsive MADD with ETFDH mutations, and they demonstrated phenotypic and genetic features similar to those of cases reported in southern China. Furthermore, we report a novel ETFDH mutation and possibly the first ever MADD patients of Malay descent.

A Case of a Patient with Calpainopathy Carrying Compound Heterozygous Mutations of a de novo Pathogenic Variant of c.1333G>A and a Novel Variant of c.1331C>T in CAPN3.

Calpainopathy is primarily an autosomal recessive inherited myopathy; however, dominantly inherited cases with a pathogenic variant of c.1333G>A have been reported. A 13-year-old Japanese girl presented with toe walking and elevated serum creatine kinase levels. Genetic panel testing revealed compound heterozygosity for c.1333G>A and a novel variant of c.1331C>T in CAPN3, leading to a diagnosis of calpainopathy. A genetic analysis of her parents revealed the possibility that c.1333G>A was de novo. In this patient, the onset age was earlier than that of the reported autosomal dominant cases, suggesting the influence of the novel variant in the contralateral allele.

Sporadic Late-onset Nemaline Myopathy Associated with Sjögren's Syndrome: A Case Report.

We report the case of a 46-year-old female patient who developed a subacute progression of axial and proximal muscle weakness. Laboratory findings revealed mildly elevated serum creatine kinase levels. No monoclonal gammopathy was detected. A muscle biopsy revealed that she had nemaline myopathy. Serological tests and a lip biopsy revealed Sjögren's syndrome (SjS). We diagnosed her as having sporadic late-onset nemaline myopathy without monoclonal gammopathy of undetermined significance associated with SjS. Her symptoms improved after methylprednisolone pulse therapy followed by intravenous immunoglobulin therapy. A good response to immunotherapy demonstrates the necessity of making a correct diagnosis, for which a muscle biopsy is required.

Clinical Features of Myasthenia Gravis as an Immune-related Adverse Event

Neurological and muscular immune-related adverse events (irAEs) associated with cancer treatment using immune checkpoint inhibitors (ICIs) may show a diverse clinical presentation. Myasthenia gravis (MG) represents a serious irAE associated with the aforementioned therapy. Recent studies have discussed the clinical features of MG that occurs as an irAE (irAE-MG). The incidence of irAE-MG is estimated to be 1%. This complication occurs during the early phase of ICI treatment and rapidly worsens, resulting in severe bulbar muscle involvement and myasthenic crisis and significantly elevated serum creatine kinase levels. MG and myositis, which may occur concomitantly as irAEs are often indistinguishable. Myocarditis is occasionally observed in patients with irAE-MG and can cause severe heart failure and lethal arrhythmias, with a fatal outcome. Kv1.4 antibodies serve as biomarkers of severe irAE-MG and myocarditis. Immunotherapy with corticosteroids is effective for management of irAE-MG and should be initiated promptly. Collaboration between consulting neurologists is necessary for safe management of cancer immunotherapy.

Ginsenoside Rg1 Attenuates Eccentric Exercise-Induced Muscle Damage via the Modulation of Lipid Peroxidation and Inflammation

Eccentric exercise (EE) may lead to skeletal muscle injury, including oxidative stress and inflammation induction. Ginsenoside Rg1, a glycosylated triterpene present in the traditional Chinese medicine ginseng, was previously shown to prevent the development of multiple diseases through the attenuation of oxidative stress and inflammation. Therefore, this article hopes to investigate whether Rg1 exhibits anti-oxidant and anti-inflammatory effects in eccentric exercise-induced muscle damage (EEIMD). Additionally, Adult male Wistar rats were intraperitoneally injected with Rg1 (20 or 40 mg/kg) every day before EE for 5 consecutive days. The impact of Rg1 administration on levels of serum creatine kinase was evaluated, followed by observation of histological muscle damage through H&amp;E staining. To assess protein nitrotyrosylation, lipid peroxidation and leukocyte infiltration in rat skeletal muscles, the levels of nitrotyrosine, MDA and MPO protein were analysed through western blotting analysis. The inflammatory response was evaluated by detecting iNOS, COX-2, IL-1β, IL-6, MCP-1 and TNF-α mRNA and protein levels in rat skeletal muscles. The regulation of Rg1 on the NF-κB pathway was examined through the analysis of phosphorylated NF-κB p65 and IκBα protein levels. Result display, EE resulted in elevated serum creatine kinase levels, widespread leukocyte infiltration, and notable muscle cell vacuolization and fragmentation in muscles. Furthermore, EE increased nitrotyrosine, MDA, MPO, iNOS, COX-2, IL-1β, IL-6, MCP-1, and TNF-α levels in rats. However, these changes were reversed by Rg1 treatment. Furthermore, EE-induced upregulation in phosphorylated NF-κB p65 and IκBα levels was counteracted by Rg1. Overall, ginsenoside Rg1 plays an anti-oxidant and anti-inflammatory role in EEIMD through suppressing this NF-κB signaling pathway.

Disease spectrum of myopathies with elevated aldolase and normal creatine kinase.

Elevation of serum creatine kinase (CK) or hyperCKemia is considered a biological marker of myopathies. However, selective elevation of serum aldolase with normal CK has been reported in a few myopathies, including dermatomyositis, immune-mediated myopathy with perimysial pathology and fasciitis with associated myopathy. The aim was to investigate the disease spectrum of myopathies with isolated aldolase elevation. Medical records were reviewed to identify patients >18 years old seen between December 1994 and June 2020 who had pathologically proven myopathies with elevated aldolase and normal CK level. Patients with alternative causes of aldolase elevation were excluded. Thirty-four patients with various types of myopathies were identified. Myopathies were treatable in 27 patients. The three most common etiologies were dermatomyositis (n = 8), overlap myositis (n = 4) and nonspecific myopathy (n = 4). Perimysial pathology comprising inflammation, fragmentation, vasculitis, calcified perimysial vessels or extracellular amyloid deposition was found in 17/34 patients (50%). Eight dermatomyositis patients with selective elevated aldolase were compared to 24 sex- and age-matched patients with dermatomyositis and hyperCKemia. Dermatomyositis patients with normal CK significantly (p < 0.05) had less frequent cutaneous involvement (50.0% vs. 100.0%) and fibrillation potentials (50.0% vs. 90.5%) but higher median erythrocyte sedimentation rate (33.5 vs. 13.5 mm/h) and more common perifascicular mitochondrial pathology (37.5% vs. 4.2%). Isolated aldolase elevation can be found in a greater variety of myopathies than initially thought and most were treatable. Dermatomyositis is the most common myopathy with selective elevation of aldolase in our cohort, which features some unique characteristics compared to dermatomyositis with hyperCKemia.

Successful treatment of seronegative immune‐mediated necrotizing myopathy developing during pregnancy: A case report and literature review

AbstractImmune‐mediated necrotizing myopathy (IMNM) is an idiopathic inflammatory myopathy characterized by limb weakness, markedly elevated serum creatine kinase (CK), and muscle fiber necrosis without lymphocytic infiltration. Here, we present a case of IMNM that developed during pregnancy. The patient was treated immediately with systemic corticosteroids, and muscle weakness and serum CK levels were improved without adverse effects on the pregnancy. As there are only a few reports of IMNM during pregnancy, the clinical course and treatment of IMNM during pregnancy are discussed with a review of the literature.

Phenotypic and genotypic analysis of a patient with Miyoshi myopathy caused by truncated protein

Dysferlin protein deficiency can cause neuromuscular dysfunction, resulting in autosomal recessive dysferlinopathy, which is caused by DYSF gene mutation. Dysferlin proteins belongs to the Ferlin1-like protein family and are associated with muscle membrane repair and regeneration. In China, pathogenic mutations of the protein often result in two clinical phenotypes of Miyoshi muscular or limb band muscular dystrophy type 2B. It is clinically characterized by progressive muscle weakness and elevated serum creatine kinase. The data of the child were collected, blood samples of the child and his family members were collected, and whole exome sequencing (WES) was performed. The recombinant expression vector was constructed, the function of the mutation was verified by minigene, and the pathogenicity of the mutation was further analyzed by combining with biological information analysis. The patient initially presented with asymptomatic elevation of serum creatine kinase（CK）. Then progressive lower limb weakness, mainly distal limb weakness. Large amounts of scattered necrosis, myogenic lesions, and complete deletion of dysferlin protein were observed under muscle biopsy, which further improved genetic detection. Whole exome sequencing showed compound mutations (c.1397 + 1_1397 + 3del and c.1375dup p.M459Nfs*15) in DYSF gene. c.1375dup p.M459Nfs*15 have been reported. The other mutation is the deletion of c.1397 + 1_1397 + 3 in Intron15, which is an intron mutation that may affect splicing and the pathogenesis is still unknown. Minigene splicing assay verified that c.1397 + 1_1397 + 3del resulted in exon15 skipping and produced a premature termination codon. We report a novel pathogenic mutation in DYSF gene with Miyoshi myopathy and demonstrate this variant causes skipping of exon15 by minigene splicing assay. We point out the need of conducting functional analysis to verify the pathogenicity of intronic mutation. The finding enriches the mutation spectrum of DYSF gene and laid a foundation for future studies on the correlation between genotype and phenotype.