目的 报告1例MYH11基因杂合新发突变导致巨膀胱-小结肠-肠蠕动不良综合征（MMIHS）患儿的临床表现与遗传信息，并通过文献回顾性分析进行基因型-表型关联研究。方法 分析2023年10月因“反复腹胀、呕吐3年余”来院就诊的MMIHS患儿临床资料，采集患儿及父母与姐姐的外周血样，通过Trio-WES及Sanger测序筛查致病突变。并对相关文献进行总结分析。结果 患儿，男，15岁，主要临床表现为频繁发作的腹胀、呕吐和腹痛，腹部立位片及上消化道造影提示肠梗阻，给予灌肠、抗感染和静脉营养支持等治疗后病情稳定。基因检测结果显示，患儿携带MYH11基因杂合新发变异c.5819delC（p.Pro1940Hisfs*91），该变异导致肌球蛋白重链C端延长，父母及姐姐均未检测出该变异。文献检索共纳入7篇与MYH11基因变异有关文献，变异类型包括错义突变、移码突变和染色体微缺失。共20例，2例因提前终止妊娠性别不明，其余患者男女比2:1。基因型-表型关联分析发现，15例携带MYH11基因延长突变显性遗传患者的发病年龄9（0~28）岁，尚未报道死亡案例。5例携带双等位基因丧失功能突变的隐性遗传患者发病年龄均小于1岁，死亡4例（80 %）。结论 本例MMIHS患儿携带MYH11基因c.5819delC（p.Pro1940Hisfs*91）变异。与携带MYH11基因变异隐性遗传的患者相比，MYH11延长突变显性遗传患者大部分发病较晚，临床表现较轻，生存率较高。

Objective To report the clinical characteristics and genetic variant of a patient with megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) and to investigate the genotypic-phenotypic correlation through literatures review. Methods The clinical data of a MMIHS child who came to our hospital in October 2023 due to "repeated abdominal distension and vomiting for more than 3 years" were analyzed. Peripheral blood samples were collected from the patient, his parents and his older sister, and the pathogenic mutation was screened by Trio-WES and Sanger sequencing. Relevant literature was summarized and analyzed. Results The patient, a 15-year-old boy, presented with recurrent episodes of abdominal distension, vomiting, and abdominal pain. Abdominal X-ray and upper gastrointestinal contrast study indicated intestinal obstruction. The condition stabilized after treatment with enema, anti-infection and intravenous nutritional support. Genetic testing revealed a heterozygous mutation in the MYH11 gene, identified as c.5819delC (p.Pro1940Hisfs*91), which resulted in the extension of the C-end of the myosin heavy chain and was not detected by either parent or sister. A total of 7 articles related to MYH11 gene mutation were included in the literature review. Mutation types included missense mutations, frameshift mutations, and chromosomal microdeletion. Gender was undetermined in 2 out of 20 patients due to early termination of pregnancy. Among the remaining patients, the male-to-female ratio was 2:1. Genotypic-phenotypic correlation analysis found that 15 patients with dominant heterozygous protein‐elongating MYH11 variants were aged 9 (0-28) years at onset, and no deaths were reported. Five patients with recessive loss-of-function mutations had an onset age of less than 1 year, with 4 deaths (80%). Conclusion This MMIHS patient carries the MYH11 gene c.5819delC (p. Pro1940Hisfs*91) mutation. Compared with patients with MYH11 gene mutation recessive inheritance, those with dominant MYH11 mutations tend to have a later onset, milder clinical manifestations, and a higher survival rate.