Matheson Kimberly A, Denomme Gregory A
Canadian Blood Services, Research and Development; Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.
Transfusion. 2002 May;42(5):645-50. doi: 10.1046/j.1537-2995.2002.00078.x.
Paternal RHD zygosity is required for genetic counseling and management of HDN caused by anti-D. The most common D- haplotype is due to the deletion of RHD, which results in the formation of a hybrid Rhesus box, theoretically through the recombination of 5' and 3'Rhesus boxes.
The validity of Rhesus box PstI analysis was assessed to determine RHD zygosity by correlating D phenotype, most probable genotype, and Rhesus box PCR-RFLP. RHD exons were examined, and a 501-bp Rhesus box fragment was sequenced that flanked the polymorphic PstI site.
Rhesus box analysis and the most probable genotype differed for 60 of 200 of the samples (30%). The incorrect zygosity assignment by the most probable genotype method is the likely reason for the difference. However, 8 of 328 samples showed Rhesus box copy numbers that were inconsistent with the D phenotype. Two D- samples with one hybrid Rhesus box had a nonfunctional RHD. Six D+ samples appeared to have two copies of the hybrid Rhesus box due to novel 3'Rhesus boxes that contained nucleotide polymorphisms previously assigned to the 5' and hybrid Rhesus boxes. All eight samples were from people of black descent, as determined by the GATA-1 silencing mutation at the FY locus.
Rhesus box PCR-RFLP analysis for RHD zygosity assignment is confounded by the presence of nonfunctional RHD+ (2.3% of D-) and novel, low frequency (0.9% of all alleles) 3'Rhesus box sequences.
对于由抗-D引起的新生儿溶血病（HDN）的遗传咨询和管理，父方RHD纯合性是必需的。最常见的D-单倍型是由于RHD缺失，理论上通过5'和3'恒河猴盒的重组导致形成杂合恒河猴盒。
通过关联D表型、最可能的基因型和恒河猴盒PCR-RFLP来评估恒河猴盒PstI分析用于确定RHD纯合性的有效性。检查RHD外显子，并对位于多态性PstI位点侧翼的501bp恒河猴盒片段进行测序。
200个样本中有60个（30%）的恒河猴盒分析结果与最可能的基因型不同。最可能的基因型方法错误的纯合性判定可能是导致差异的原因。然而，328个样本中有8个显示恒河猴盒拷贝数与D表型不一致。两个具有一个杂合恒河猴盒的D-样本有一个无功能的RHD。六个D+样本似乎有两个杂合恒河猴盒拷贝，这是由于新的3'恒河猴盒含有先前分配给5'和杂合恒河猴盒的核苷酸多态性。根据FY位点的GATA-1沉默突变确定，所有八个样本均来自黑人后裔。
用于RHD纯合性判定的恒河猴盒PCR-RFLP分析因存在无功能的RHD+（占D-的2.3%）和新的低频（占所有等位基因的0.9%）3'恒河猴盒序列而受到干扰。
