Today, the research on X chromosome translocations has focused on skewed X-chromosome inactivation(XCI) and pseudo-autosomal regions (PARs). PARs are classified as PAR1 and PAR2, the latter located on the qter of chromosome X with a size of about 360 kb including the SPRY3, SYBL1, and IL9R genes, which played a key role in antagonistic pathway of fibroblast growth factor (FGF) synthesis, fusion of vesicles and target membrane and occurrence of asthma respectively [11–13]. The gene discussed is IL9R; the disease is asthma.