Cat eye syndrome chromosome breakpoint clustering: identification of two intervals also associated with 22q11 deletion syndrome breakpoints
Cat eye syndrome chromosome breakpoint clustering: identification of two intervals also associated with 22q11 deletion syndrome breakpoints
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DOI：
10.1159/000015035
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发表时间：
1998-01-01
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影响因子：
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通讯作者：
McDermid, HE
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文献类型：
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作者：
McTaggart, KE;Budarf, ML;McDermid, HE
多余猫眼综合症（CES）染色体是双着丝粒的，包含两个22pter-->q11.2拷贝。我们发现重复断点聚集在两个区间。更近端、最常见的间隔是 D22S427 和 D22S36 之间的 450-650 kb 区域，对应于 22q11 缺失综合征（DiGeorge/velocardiofacial 综合征）中发现的近端缺失断点间隔。更远端的重复断点间隔位于 CRKL 和 D22S112 之间，与 22q11 缺失综合征常见的远端缺失间隔重叠。因此，我们根据生成 CES 染色体所需的两个断点的位置将其分为两种类型。较小的 I 型 CES 染色体是对称的，两个断点都位于近端区间内。较大的 II 型 CES 染色体要么不对称，两个间隔各有一个断点，要么对称，两个断点都位于远端间隔。这些不同综合征断点的共定位，加上每个间隔附近存在低拷贝重复，表明 22q11.2 中存在几个染色体不稳定的特定区域，这些区域参与缺失和重复的产生。由于与较大重复相关的表型似乎并不比较小重复更严重，因此 CES 染色体类型的确定目前不具有预后价值。
The supernumerary cat eye syndrome (CES) chromosome is dicentric, containing two copies of 22pter-->q11.2. We have found that the duplication breakpoints are clustered in two intervals. The more proximal, most common interval is the 450-650 kb region between D22S427 and D22S36, which corresponds to the proximal deletion breakpoint interval found in the 22q11 deletion syndrome (DiGeorge/velocardiofacial syndrome). The more distal duplication breakpoint interval falls between CRKL and D22S112, which overlaps with the common distal deletion interval of the 22q11 deletion syndrome. We have therefore classified CES chromosomes into two types based on the location of the two breakpoints required to generate them. The smaller type I CES chromosomes are symmetrical, with both breakpoints located within the proximal interval. The larger type II CES chromosomes are either asymmetrical, with one breakpoint located in each of the two intervals, or symmetrical, with both breakpoints located in the distal interval. The co-localization of the breakpoints of these different syndromes, plus the presence of low-copy repeats adjacent to each interval, suggests the existence of several specific regions of chromosomal instability in 22q11.2 which are involved in the production of both deletions and duplications. Since the phenotype associated with, the larger duplication does not appear to be more severe than that of the smaller duplication, determination of the type of CES chromosome does not currently have prognostic value.