Department of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China.
Transfusion. 2013 Jun;53(6):1266-9. doi: 10.1111/j.1537-2995.2012.03863.x. Epub 2012 Aug 23.
Uniparental disomy (UPD) is a rare cytogenetic event that has previously been reported mostly via genetic analysis of patients with phenotypes of recessive diseases. The incidence of UPD of any chromosome is estimated to be approximately1:3500 live births.
In a case of disputed paternity involving a phenotypically normal male child, mother-child exclusions were observed at five short tandem repeat markers, which were all located on Chromosome 2. Ten additional dinucleotide repeat markers spanning both arms of Chromosome 2 were investigated. The results revealed that the child was homozygous for all markers tested with all alleles originating from a single paternal Chromosome 2, which was consistent with paternal UPD for Chromosome 2.
This case and other previous reports demonstrate that UPD poses a high risk for false exclusion and incorrect expert opinion. Furthermore, this case highlights that a conclusion of exclusion of paternity or maternity should not be postulated if multiple genetic incompatibilities are located on the same chromosome because of the occurrence of UPD.
单亲二体（UPD）是一种罕见的细胞遗传学事件，以前主要通过隐性疾病表型患者的遗传分析进行报道。任何染色体的 UPD 发生率估计约为每 3500 例活产 1 例。
在涉及表型正常男性儿童的亲子关系争议案例中，在五个短串联重复标记物上观察到母子排除，这些标记物均位于 2 号染色体上。研究了另外 10 个位于 2 号染色体臂上的二核苷酸重复标记物。结果显示，孩子对所有测试标记物均为纯合子，所有等位基因均来自单一父系 2 号染色体，这与 2 号染色体的父系 UPD 一致。
本案例和其他先前的报告表明，UPD 存在高度的假排除和错误专家意见的风险。此外，本案例强调，如果多个遗传不相容性位于同一染色体上，由于 UPD 的发生，不应假设亲子关系排除的结论。
