Robinson W P
Department of Medical Genetics, University of British Columbia, B.C. Research Institute for Children's & Women's Health, Vancouver, Canada.
Bioessays. 2000 May;22(5):452-9. doi: 10.1002/(SICI)1521-1878(200005)22:5<452::AID-BIES7>3.0.CO;2-K.
Uniparental disomy (UPD) refers to the situation in which both copies of a chromosome pair have originated from one parent. In humans, it can result in clinical conditions by producing either homozygosity for recessive mutations or aberrant patterns of imprinting. Furthermore, UPD is frequently found in conjunction with mosaicism for a chromosomally abnormal cell line, which can also contribute to phenotypic abnormalities. Investigations into the mechanisms by which UPD may arise have helped to expand our general awareness of the impact of chromosomal abnormalities and chromosomal mosaicism in normal human development. Specifically, it appears that errors in the transmission of a chromosome from parent to gamete and during early somatic cell divisions are remarkably common but that embryo and cell selection during early embryogenesis help to ensure the presence of a numerically balanced chromosome complement in the developing fetus. UPD is also likely to occur within a portion of cells in all individuals simply as a consequence of somatic recombination occurring during mitotic cell divisions. This can be an important step in cancer development as well as a contributing factor to other late onset diseases. This review summarizes mechanisms by which UPD may arise and their associated clinical consequences.
单亲二体（UPD）是指一对染色体的两个拷贝均来自同一亲本的情况。在人类中，它可通过产生隐性突变的纯合性或异常的印记模式而导致临床病症。此外，UPD常与染色体异常细胞系的嵌合体同时出现，这也可导致表型异常。对UPD可能产生的机制的研究有助于扩大我们对染色体异常和染色体嵌合体在正常人类发育中的影响的总体认识。具体而言，似乎染色体从亲本传递到配子以及在早期体细胞分裂过程中出现的错误非常常见，但早期胚胎发育过程中的胚胎和细胞选择有助于确保发育中的胎儿存在数量平衡的染色体组。UPD也可能仅由于有丝分裂细胞分裂期间发生的体细胞重组而在所有个体的一部分细胞内出现。这可能是癌症发展的重要步骤以及其他晚发性疾病的一个促成因素。本综述总结了UPD可能产生的机制及其相关的临床后果。
