Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway.
Gene. 2014 Jan 1;533(1):403-10. doi: 10.1016/j.gene.2013.09.090. Epub 2013 Oct 2.
Chromosomal rearrangements resulting in an inverted duplication and a terminal deletion (inv dup del) can occur due to three known mechanisms, two of them resulting in a normal copy region between the duplicated regions. These mechanisms involve the formation of a dicentric chromosome, which undergo breakage during cell division resulting in cells with either an inverted duplication and deletion or a terminal deletion. We describe a mosaic 3 year old patient with two cell lines carrying a chromosome 9p deletion where one of the cell lines contains an additional telocentric marker chromosome. Our patient is mosaic for the product of a double breakage of a dicentric chromosome including a centric fission. Mosaicism involving different rearrangements of the same chromosome is rare and suggests an early mitotic breakage event. Chr9p terminal deletions associated with duplications have previously been reported in 11 patients. We compare the clinical features of all 12 patients including the patient that we report here. To the best to our knowledge this is a first case reported where the double breakage occurred in the dicentric derivative chromosome 9.
由于三种已知机制，可能会发生导致倒位重复和末端缺失（inv dup del）的染色体重排，其中两种机制导致重复区域之间存在正常的拷贝区域。这些机制涉及双着丝粒染色体的形成，在细胞分裂过程中发生断裂，导致细胞具有倒位重复和缺失或末端缺失。我们描述了一名 3 岁的镶嵌患者，携带 9p 染色体缺失的两个细胞系，其中一个细胞系含有额外的近端着丝粒标记染色体。我们的患者是双着丝粒染色体断裂的产物的镶嵌体，包括着丝粒分裂。涉及同一染色体不同重排的镶嵌体很罕见，提示早期有丝分裂断裂事件。先前在 11 名患者中报道了与重复相关的 9p 末端缺失。我们比较了包括我们在此报告的患者在内的所有 12 名患者的临床特征。据我们所知，这是首例报告双断裂发生在双着丝粒衍生的 9 号染色体上的病例。
