目的　探讨免疫缺陷、着丝粒不稳定和面部异常（ICF）综合征的临床特征和遗传特点。方法　回顾分析1 例ICF综合征患儿的临床资料和基因检测结果。结果　男性患儿， 4岁，有反复感染；面部特征为圆脸、眼距稍宽、下颌 尖、鼻梁稍扁、内眦赘皮明显、耳位低。免疫学检测示IgA缺如。基因测序发现患儿DNMT3B基因存在一个纯合错义突变 c.2506G>A，父母为杂合携带者，确诊为ICF综合征I型。结论　DNMT3B基因突变可引发ICF综合征，基因检测有助于提 高此类罕见病的诊断。

Objective　To investigate the clinical and genetic characteristics of immunodeficiency, centromeric instability and facial anomalies syndrome (ICF) and promote recognition of this disorder among Chinese population. Methods　A retrospective review of the clinical characteristics, immunoassay and gene sequencing data of this ICF syndrome was conducted. Results　The main symptom of the patient was recurrent infection. Facial dysmorphism was mild, including a round face, hypertelorism, pointed chin, flat nasal bridge, epicanthus and low-set ears. Immunodeficiency was observed in the patient and IgA level was almost null. A homozygous missense mutation c.2506G>A was found in DNMT3B by gene sequencing, and his parents were both heterozygous mutation carriers. This case was designated as ICFⅠpatient. Conclusion　Mutation in DNMT3B is the cause of ICF syndrome. Clinical features and gene test can help confirm this rare genetic disease.