OBJECTIVE: To investigate the genetic etiology of six adult patients with Dilated cardiomyopathy (DCM), and analyze the structure of the identified variants, for providing reference for the diagnosis of DCM. METHODS: Six adult patients with DCM (patients 1-6) admitted to the Department of Cardiology of Zhumadian Central Hospital from January 2023 to December 2023 were recruited. Clinical data of the patients were retrospectively collected. And 5 mL of peripheral blood was collected from each patient. Pathogenic variants of the patients were detected by whole exome sequencing (WES), and candidate variants were verified by Sanger sequencing. The possible functional significance of the identified missense variants was evaluated using software including SIFT, PolyPhen-2 and Mutation Taster. Specific regions of the MYBPC protein encoded by the MYBPC3 gene from different species were aligned using Mutation Taster. The wild-type and mutant MYBPC proteins were constructed using homologous modeling software MODELLER v10.4 and three-dimensional structures were visualized using PyMOL software. The molecular interaction between MYBPC-C5 domain and myosin with or without the mutation was further analyzed using ZDOCK module in Discovery Studio 2019 software. Pathogenicity ratings for the detected variant sites were performed in accordance with the Standards and Guidelines for the Interpretation of Sequence variants by the American College of Medical Genetics and Genomics (ACMG) (hereafter referred to as the ACMG Guidelines). This study was reviewed and approved by the Ethics Committee of Zhumadian Central Hospital (Approval No. 2022092007). RESULTS: The six DCM patients had typical symptoms of heart failure, and echocardiography showed whole-heart dilation and decreased ventricular wall motion, left ventricular end-diastolic dimension (LVEDD) was 59-74 mm, left ventricular ejection fraction (LVEF) was 35%-43%, and left ventricular fractional shortening (LVFS) was 17%-28%. Variations of the DCM related genes, including a c.98473A>T (p.Lys32825*) variation of the TTN gene and a c.1976T>C (p.Ile659Thr) variation of the MYBPC3 gene, were identified in two patients. Multiple software predicted that both mutations were deleterious. MYBPC3-Ile659Thr mutation affected the highly conserved residue within the C5 domain of MYBPC. Three-dimensional structural analysis of homologous modeling revealed the alterations in amino acid properties and interactions with surrounding amino acids caused by the MYBPC3-Ile659Thr mutation. Further molecular docking analysis showed that the Ile659Thr mutation altered both the hydrogen bond and salt-bridge interactions between the MYBPC-C5 domain and the ligand myosin. CONCLUSION Two mutations associated with DCM were identified in this study. The abnormal conformation of the mutant protein further affected its interaction with the ligand myosin, resulting in the phenotype of DCM.
Humans ; Cardiomyopathy, Dilated/genetics* ; Male ; Adult ; Female ; Carrier Proteins/chemistry* ; Middle Aged ; Mutation ; Exome Sequencing ; Mutation, Missense ; Retrospective Studies ; Myosin Binding Protein C

Objective To explore the risk factors of frozen shoulder,and to provide the basis for the prevention of frozen shoulder.Methods A total of 114 patients with frozen shoulder who were hospitalized in the First Affiliated Hospital of Zhejiang Chinese Medical University from January 2020 to August 2022 were included in case group,and 114 physical examination patients with no history of frozen shoulder were included in control group.The clinical data of two groups were collected and the risk factors of frozen shoulder were analyzed by multivariate Logistic regression.Results There were statistically significant differences in cervical radiculopathy,type 2 diabetes mellitus,hepatitis,chronic non-atrophic gastritis,lumbar disc herniation,osteoporosis and thyroid sarcoidosis between two groups(P<0.05).Multivariate Logistic analysis showed that cervical radiculopathy(OR=6.114,95%CI:1.458-25.642)and type 2 diabetes mellitus(OR=24.069,95%CI:4.023-144.007)were independent risk factors for the onset of frozen shoulder.Conclusion Patients with type 2 diabetes mellitus and cervical radiculopathy have a higher risk of frozen shoulder,and should pay attention to early prevention.