Jespersgaard Cathrine, Damgaard Ida N, Cornelius Nanna, Bache Iben, Knabe Niels, Miranda Maria J, Tümer Zeynep
Department of Clinical Genetics, Applied Human Molecular Genetics, Kennedy Center, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark.
Department of Paediatrics, Copenhagen University Hospital, Herlev, Denmark.
Mol Cytogenet. 2016 Feb 4;9:11. doi: 10.1186/s13039-016-0220-5. eCollection 2016.
IInterstitial 21q deletions can cause a wide spectrum of symptoms depending on the size and the location of the deletion. It has previously been suggested that the long arm of chromosome 21 can be divided into three regions based on the clinical severity of the patients and deletion of the region from 32.3 Mb to 37.1 Mb was more crucial than the deletion of other regions.
In this study we describe a female patient with dysmorphic features, hepatomegaly, thick myocardium and psychomotor delay. Conventional karyotyping was initially interpreted as full monosomy 21, but subsequent chromosome microarray analysis suggested an approximately 18 Mb partial monosomy. Re-evaluation of the karyotype and fluorescence in situ hybridization revealed deletion of the proximal 21q11.2-q22.11 segment and insertion of 21q22.11-qter to 12qter. The deletion of the present case overlaps with two of the proposed regions including part of the proposed crucial region.
This report emphasizes the relevance of investigating suspected full monosomies with high resolution methods and FISH in order to investigate the extent of the deletion and the presence of more complex rearrangements.
21号染色体间质缺失可导致一系列广泛的症状，具体取决于缺失的大小和位置。此前有研究表明，根据患者的临床严重程度，21号染色体长臂可分为三个区域，从32.3兆碱基对至37.1兆碱基对区域的缺失比其他区域的缺失更为关键。
在本研究中，我们描述了一名具有畸形特征、肝肿大、心肌增厚和精神运动发育迟缓的女性患者。传统核型分析最初被解释为完全21号单体，但随后的染色体微阵列分析表明存在约18兆碱基对的部分单体。对核型的重新评估和荧光原位杂交显示近端21q11.2 - q22.11片段缺失，以及21q22.11 - qter插入到12qter。本病例的缺失与两个提议区域重叠，包括部分提议的关键区域。
本报告强调了采用高分辨率方法和荧光原位杂交技术对疑似完全单体进行研究的重要性，以便确定缺失的范围以及是否存在更复杂的重排。
