Uniparental disomy (UPD) is defined as two copies of a whole chromosome derived from the same parent. There can be multiple mechanisms that lead to UPD; these are reviewed in the context of contemporary views on the mechanism leading to aneuploidy. Recent studies indicate that UPD is rare in an apparently healthy population and also rare in spontaneous abortion tissues. The most common type of UPD is a maternal heterodisomy (both maternal allele sets present). Isodisomy (a duplicated single set of alleles) or segmental loss of heterozygosity is sometimes encountered in SNP‐based microarray referrals. Decisions regarding the most appropriate follow‐up testing should consider the possibility of consanguinity (that will generally involve multiple regions), an imprinted gene disorder (chromosomes 6, 7, 11, 14, 15, 20), expression of an autosomal recessive disorder, and an occult aneuploid cell line that may be confined to the placenta. Upd(16)mat, per se, does not appear to be associated with an abnormal phenotype. UPD provides an insight into the history of early chromosome segregation error and understanding the rates and fate of these events are of key importance in the provision of fertility management and prenatal healthcare.

中文翻译：

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单亲二体性：起源、频率和临床意义

单亲二体性 (UPD) 被定义为来自同一亲本的整个染色体的两个拷贝。可能有多种机制导致 UPD；这些是在当代关于导致非整倍体的机制的观点的背景下进行审查的。最近的研究表明，UPD 在明显健康的人群中很少见，在自然流产组织中也很少见。最常见的 UPD 类型是母体异源性（两个母体等位基因组都存在）。在基于 SNP 的微阵列转诊中有时会遇到同二体性（一组重复的单组等位基因）或杂合性的节段性丢失。关于最合适的后续检测的决定应考虑血缘关系（通常涉及多个区域）、印迹基因疾病（染色体 6、7、11、14、15、20）的可能性，常染色体隐性遗传疾病的表达，以及可能局限于胎盘的隐匿性非整倍体细胞系。Upd(16)mat 本身似乎与异常表型无关。UPD 提供了对早期染色体分离错误历史的洞察，了解这些事件的发生率和命运对于提供生育管理和产前保健至关重要。