Grootkerk-Tax Martine G H M, Maaskant-van Wijk Petra A, van Drunen Judith, van der Schoot C Ellen
Sanquin Research at CLB, Amsterdam, the Netherlands.
Transfusion. 2005 Mar;45(3):327-37. doi: 10.1111/j.1537-2995.2005.04199.x.
Knowledge about paternal RHD hemi- or homozygosity is of clinical interest in alloimmunized pregnant women. D negativity in white persons is usually caused by deletion of the RHD gene. Recently, the physical structure of the RH locus and the mechanism causing the deletion of the RHD gene have been explored, enabling RHD zygosity determination in white persons by specific detection of a hybrid Rhesus box characteristic for the RHD- locus.
RHD zygosity was determined in 402 samples from five different ethnic groups by polymerase chain reaction (PCR)-restriction fragment length polymorphism and by a newly developed real-time quantitative PCR. The Rhesus boxes of samples showing discrepancies between both tests were cycle sequenced.
In nonwhite persons, several mutated Rhesus boxes exist that hamper zygosity determination by detection of the RHD- locus. Such mutated Rhesus boxes in D+RHD homozygous black persons have a frequency of 0.22. In white persons, no mutated Rhesus boxes were encountered so far.
Owing to the high frequency of the mutated Rhesus boxes, zygosity determination by detection of the RHD- locus is not feasible in nonwhite persons. The cosegregation of variant RHD genes (RHDpsi and (C)cdes) with specific mutated Rhesus boxes yields more insight into the evolutionary events concerning variant RHD genes and mutated Rhesus boxes.
对于同种免疫的孕妇，了解父亲的RHD半合子或纯合子情况具有临床意义。白人中的D阴性通常是由RHD基因缺失引起的。最近，人们对RH基因座的物理结构以及导致RHD基因缺失的机制进行了探索，从而能够通过特异性检测RHD-基因座特有的杂交恒河猴盒来确定白人的RHD合子性。
采用聚合酶链反应（PCR）-限制性片段长度多态性以及新开发的实时定量PCR方法，对来自五个不同种族的402份样本进行RHD合子性测定。对两种检测结果存在差异的样本的恒河猴盒进行循环测序。
在非白人中，存在几种突变的恒河猴盒，这妨碍了通过检测RHD-基因座来确定合子性。D+RHD纯合黑人中这种突变恒河猴盒的频率为0.22。在白人中，目前尚未发现突变的恒河猴盒。
由于突变恒河猴盒的高频率，通过检测RHD-基因座来确定非白人的合子性是不可行的。变异RHD基因（RHDpsi和（C）cdes）与特定突变恒河猴盒的共分离，使我们对变异RHD基因和突变恒河猴盒的进化事件有了更多了解。
