Abstract: 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.

Key words: 　ICF syndrome;　clinical manifestations;　mutation of DNMT3B;　gene sequencing