Immunodeficiency, centromeric instability and facial anomalies syndrome (ICF) is a rare autosomal recessive disorder, which is characteristic of a severe impairment of immunity. In the genetic aspect, ICF is featured with mutations primarily located in the specific genes (DNMT3B for ICF1, ZBTB24 for ICF2, CDCA7 for ICF3, and HELLS for ICF4). The subtelomeric region is defined as 500 kb at the terminal of each autosomal arm. And subtelomeric DNA fragments can partially regulate key biological activities, including chromosome movement and localization in the nucleus. In this review, we updated and summarized gene mutations in ICF based on the previous review. In addition, we focused on the correlation between subtelomeric DNA methylation and ICF. The relationship between subtelomeric methylation and telomere length in ICF was also summarized.

中文翻译：

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免疫缺陷，着丝粒不稳定性和面部异常综合征的基因突变和亚端粒DNA甲基化。

免疫缺陷，着丝粒不稳定和面部异常综合症（ICF）是一种罕见的常染色体隐性遗传疾病，其特征是免疫力严重受损。在遗传方面，ICF具有主要位于特定基因中的突变（ICF1为DNMT3B，ICF2为ZBTB24，ICF3为CDCA7，ICF4为HELLS）。在每个常染色体臂的末端，亚端粒区域定义为500 kb。亚端粒DNA片段可以部分调节关键的生物学活性，包括染色体运动和核内定位。在这篇综述中，我们根据之前的综述更新并总结了ICF中的基因突变。此外，我们专注于亚端粒DNA甲基化与ICF之间的相关性。还总结了ICF中亚端粒甲基化与端粒长度之间的关系。