摘要目的:探讨8例肥厚型心肌病(HCM)患儿的临床及遗传学特点。方法:选取2018年1月至2021年12月河南省儿童医院心内科收治的8例HCM患儿作为研究对象，收集患儿的临床资料。对其中2例患儿采用单人全外显子组测序，6例患儿及其父母采用家系全外显子组测序。应用Sanger测序对患儿及其父母进行候选变异验证，并按照美国医学遗传学与基因组学学会(ACMG)相关变异标准与指南对变异进行致病性分析。结果:8例患儿中，男5例，女3例，年龄在5个月~13岁之间，平均确诊年龄为(7.87±4.8)岁，心脏表型均提示非梗阻性HCM。基因检测提示4例患儿 MYH7基因存在变异，分别为c.2155C>T(p.Arg719Trp)、c.1208G>A(p.Arg403Gln)、c.1358G>A(p.Arg453His)以及c.1498G>A(p.Glu500Lys)。依据ACMG相关变异评级指南，前3种变异均评级为致病性变异，c.1498G>A(p.Glu500Lys)评级为可能致病性变异(PM1＋PM2_Supporting＋PM6＋PP3)，既往未见报道。另4例患儿存在母源变异，其中 MYL2：c.173G>A(p.Arg58Gln)评级为致病性变异， TPM1：c.574G>A(p.Glu192Lys)、 ACTC1：c.301G>A(p.Glu101Lys)均评级为可能致病性变异， MYBPC3：c.146T>G(p.Ile49Ser)评级为意义未明。予以7例患儿0.5~3 mg/(kg·d)普萘洛尔治疗，症状明显好转，并随访至2022年9月30日未再发生心脏事件。 结论:对不明原因的心肌病进行基因检测可以明确其致病原因，为临床诊断提供依据，并为遗传咨询提供参考。 MYH7基因变异c.1498G>A(p.Glu500Lys)的发现拓展了肥厚型心肌病基因变异谱。

abstractsObjective:To explore the clinical and genetic characteristics of eight children with primary hypertrophic cardiomyopathy (HCM).Methods:Eight children with HCM admitted to the Department of Cardiology of Henan Children′s Hospital from January 2018 to December 2021 were selected as the study subjects. Clinical data of the children were collected. Whole exome sequencing was carried out on two children, and trio whole exome sequencing was carried out on the remainder 6 children. Sanger sequencing was used to verify the candidate variants in the children and their parents, and the pathogenicity of the variants was evaluated based on the guidelines from the American College of Medical Genetics and Genomics (ACMG).Results:The patients had included 5 males and 3 females, with their ages ranging from 5 to 13 years old. The average age of diagnosis was (7.87 ± 4.8) years old, and the cardiac phenotype showed non-obstructive HCM in all of the patients. WES has identified variants of the MYH7 gene in 4 children, including c. 2155C>T (p.Arg719Trp), c. 1208G>A (p.Arg403Gln), c. 1358G>A (p.Arg453His), and c. 1498G>A (p.Glu500Lys). Based on the guidelines from the ACMG, the first 3 variants were classified as pathogenic, while c. 1498G>A (p.Glu500Lys) was classified as likely pathogenic (PM1+ PM2_Supporting+ PM6+ PP3), which was also unreported previously. The remaining four children had all harbored maternal variants, including MYL2: c. 173G>A (p.Arg58Gln; classified as pathogenic), TPM1: c. 574G>A (p.Glu192Lys) and ACTC1: c. 301G>A (p.Glu101Lys) (both were classified as likely pathogenic), and MYBPC3: c. 146T>G (p.Ile49Ser; classified as variant of uncertain significance). Seven children were treated with 0.5 ~ 3 mg/(kg·d) propranolol, and their symptoms had improved significantly. They were followed up until September 30, 2022 without further cardiac event. Conclusion:Genetic testing can clarify the molecular basis for unexplained cardiomyopathy and provide a basis for clinical diagnosis and genetic counseling. Discovery of the c. 1498G>A (p.Glu500Lys) variant has also expanded the spectrum of MYH7 gene mutations underlying HCM.