Medical Genomics LLC, 48 Zhelyabov Str, Tver, 170100, Russian Federation.
Mol Genet Genomics. 2023 Nov;298(6):1389-1394. doi: 10.1007/s00438-023-02064-8. Epub 2023 Sep 1.
Uniparental disomy (UPD) is a rare chromosomal condition, which apart from its importance in medical genetics can affect an outcome of parentage DNA testing, often causing pseudo exclusions. We describe a case of trio paternity test using 24 informative STR loci with potential exclusion at 2 systems located on chromosome 21. Consequent genotyping of an additional 25 autosomal and 27 Y-specific STRs revealed one other inconsistency, also located on this chromosome. All three inconsistent markers had the same heteroallelic state between the child and the biological mother providing evidence for maternal heterodisomy of chromosome 21. The case highlights the importance of considering UPD as a cause of genetic inconsistencies, especially when the inconsistent marker systems are located on the same chromosome.
单亲二体（UPD）是一种罕见的染色体情况，除了在医学遗传学中的重要性外，还可能影响亲子 DNA 检测的结果，通常导致假排除。我们描述了使用 24 个信息丰富的 STR 位点对三父子进行亲子鉴定的案例，这两个系统位于 21 号染色体上，具有潜在的排除性。随后对另外 25 个常染色体和 27 个 Y 特异性 STR 进行基因分型，发现另一个不一致的标记也位于这条染色体上。三个不一致的标记在孩子和生母之间都具有相同的杂合等位状态，这为 21 号染色体的母体单亲二体提供了证据。该案例强调了将 UPD 视为遗传不一致的原因的重要性，特别是当不一致的标记系统位于同一染色体上时。
