Duplications of the Xq28 region are the most frequent chromosomal aberrations observed in patients with intellectual disability (ID), especially in males. These duplications occur by variable mechanisms, including interstitial duplications mediated by segmental duplications in this region and terminal duplications (functional disomy) derived from translocation with other chromosomes. The most commonly duplicated region includes methyl CpG-binding protein 2 gene (MECP2), which has a minimal duplicated size of 0.2 Mb. Patients with MECP2 duplications show severe ID, intractable seizures and recurrent infections. Duplications in the telomeric neighboring regions, which include GDP dissociation inhibitor 1 gene (GDI1) and ras-associated protein RAB39B gene (RAB39B), are independently associated with ID, and many segmental duplications located in this region could mediate these frequently observed interstitial duplications. In addition, large duplications, including MECP2 and GDI1, induce hypoplasia of the corpus callosum. Abnormalities observed in the white matter, revealed by brain magnetic resonance imaging, are a common finding in patients with MECP2 duplications. As primary sequence analysis cannot be used to determine the region responsible for chromosomal duplication syndrome, finding this region relies on the collection of genotype-phenotype data from patients.

中文翻译：

---

Xq28基因组拷贝数增加的临床影响。

Xq28区域的重复是在智障（ID）患者（尤其是男性）中观察到的最常见的染色体畸变。这些重复通过可变机制发生，包括由该区域中的节段重复介导的间质重复和源自与其他染色体易位的末端重复（功能性二体性）。最常见的重复区域包括甲基CpG结合蛋白2基因（MECP2），其最小重复大小为0.2 Mb。重复MECP2的患者显示严重的ID，顽固的癫痫发作和反复感染。端粒邻近区域的重复，包括GDP离解抑制剂1基因（GDI1）和ras相关蛋白RAB39B基因（RAB39B），与ID独立相关，并且位于该区域的许多节段重复可以介导这些经常观察到的间隙重复。此外，包括MECP2和GDI1在内的大量重复会导​​致call体发育不全。脑磁共振成像显示，在白质中观察到的异常是MECP2重复患者常见的发现。由于一级序列分析不能用于确定负责染色体复制综合征的区域，因此发现该区域依赖于患者基因型-表型数据的收集。是MECP2重复患者常见的发现。由于一级序列分析不能用于确定负责染色体复制综合征的区域，因此发现该区域依赖于患者基因型-表型数据的收集。是MECP2重复患者常见的发现。由于一级序列分析不能用于确定负责染色体复制综合征的区域，因此发现该区域依赖于患者基因型-表型数据的收集。