Primary immunodeficiencies (PIDs) are associated with deleterious mutations of genes that encode proteins involved in actin cytoskeleton reorganisation. This deficiency affects haematopoietic cells. PID results in the defective function of immune cells, such as impaired chemokine-induced motility, receptor signalling, development and maturation. Some of the genes mutated in PIDs are related to small Ras homologous (Rho) guanosine triphosphatase (GTPase), one of the families of the Ras superfamily. Most of these genes act as molecular switches by cycling between active guanosine triphosphate-bound and inactive guanosine diphosphate-bound forms to control multiple cellular functions. They are best studied for their role in promoting cytoskeleton reorganisation, cell adhesion and motility. Currently, only three small Rho GTPases, namely, Rac2, Cdc42 and RhoH, have been identified in PIDs. However, several other Rho small G proteins might also contribute to the deregulation and phenotype observed in PIDs. Their contribution in PIDs may involve their main regulator, Rho guanine nucleotide exchange factors such as DOCK2 and DOCK8, wherein mutations may result in the impairment of small Rho GTPase activation. Thus, this review outlines the potential contribution of several small Rho GTPases to the promotion of PIDs.

原发性免疫缺陷 (PID) 与编码参与肌动蛋白细胞骨架重组的蛋白质的基因的有害突变有关。这种缺陷会影响造血细胞。PID 导致免疫细胞功能缺陷，例如趋化因子诱导的运动、受体信号传导、发育和成熟受损。PID 中的一些突变基因与小 Ras 同源 (Rho) 鸟苷三磷酸酶 (GTPase) 相关，后者是 Ras 超家族的家族之一。大多数这些基因通过在活性鸟苷三磷酸结合形式和非活性鸟苷二磷酸结合形式之间循环来充当分子开关，以控制多种细胞功能。它们在促进细胞骨架重组、细胞粘附和运动方面的作用得到了最好的研究。目前，只有三个小的 Rho GTPase，即 Rac2、Cdc42 和 RhoH 已在 PID 中得到鉴定。然而，其他几种 Rho 小 G 蛋白也可能导致在 PID 中观察到的失调和表型。它们在 PID 中的贡献可能涉及它们的主要调节因子，Rho 鸟嘌呤核苷酸交换因子，例如 DOCK2 和 DOCK8，其中突变可能导致小 Rho GTPase 激活受损。因此，本综述概述了几种小型 Rho GTP 酶对促进 PID 的潜在贡献。