目的　探讨3M综合征的临床特征及致病基因。方法　回顾分析1例3M综合征患儿的临床资料，并抽提患 儿及父母外周血DNA，通过Agilent SureSelect外显子捕获和Illumina HiSeq测序平台进行测序分析，同时对发现的突变基 因进行Sanger测序法验证。结果　女性患儿， 6月龄，特殊面容，生长落后。患儿的CUL7基因（NM_014780.4）存在错义 变异c.4898C>T，p.T1633M，父母均为杂合突变。确诊为3M综合征。结论　患儿为3M综合征主要致病基因CUL7突变。 对于临床表型疑似病例应早期进行基因检测以明确诊断。

Objective　To investigate the clinical features and gene mutations of 3M syndrome. Method　The clinical data of a child with 3M syndrome was retrospectively analyzed. The DNA was extracted from the peripheral blood of the child and parents, and the sequence analyses were performed by Agilent SureSelect exon capture and Illumina HiSeq sequencing platform. And the mutant gene was validated by Sanger sequencing. Results　The six-month-old girl presented special face and growth retardation. The girl had a missense mutation c.4898C>T, p.T1633M in the CUL7 gene (NM_014780.4), and both her parents had heterozygous mutations. The girl was diagnosed with 3M syndrome. Conclusions　The CUL7 mutation is the major causative gene of 3M syndrome in this girl. Early gene testing should be performed to confirm the diagnosis in suspected clinical phenotype.