Interstitial deletion of 13q and a 13;X chromosome translocation results in partial trisomy 13 and bilateral retinoblastoma
Interstitial deletion of 13q and a 13;X chromosome translocation results in partial trisomy 13 and bilateral retinoblastoma
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13q 和 13;X 染色体易位的间质缺失导致部分 13 三体性和双侧视网膜母细胞瘤
DOI：
10.1076/opge.24.3.175.15612
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发表时间：
2003
影响因子：
1.2
通讯作者：
S. Dobin
中科院分区：
文献类型：
--
作者：
David C. Dries;K. Baca;L. Truss;S. Dobin
背景：13号染色体异常与双侧视网膜母细胞瘤有关。视网膜母细胞瘤基因缺失是常见的主要机制。其他异常情况则更为罕见。据我们所知，与双侧视网膜母细胞瘤相关的X和13染色体长臂平衡易位已被报道过五次。我们报告一个不平衡的X；13易位导致部分三体13和一个Rb基因座的间隙缺失。方法：病例报告。结果：一名19个月大的儿童在急诊科出现癫痫发作。CT扫描显示双眼内钙化，眼科检查证实为视网膜母细胞瘤(RB)。异常相和发育延缓现象。在骨髓和外周血细胞中均观察到X；13易位所致的部分三体。荧光原位杂交(FISH)研究证实了13号染色体Q臂上跨越Rb基因座的一个区域的三倍体。其中一个正常的13号染色体同源物有Rb基因的间隙缺失，因为尽管存在13q14区域，但没有观察到Rb-1探针的信号。发现的典型面部特征和发育迟缓支持间质缺失的其他证据。推测，易位的X经历了X失活，排除了在13三体中观察到的典型的全身特征。双亲核型正常。染色体异常是一种从头开始的体质事件。结论：尽管存在13q的三倍体，但在该患者中仅存在两个Rb基因座。第三个基因座被删除。我们认为第二个基因不表达是由于Der(X)t(Xq：13q)染色体上的Rb基因X失活所致。双侧视网膜母细胞瘤的出现表明肿瘤细胞中剩余的第三个和最后一个Rb基因位点缺乏杂合性。据我们所知，视网膜母细胞瘤的不平衡易位导致部分三体13尚未见报道。
Background: Abnormalities of chromosome 13 have been associated with bilateral retinoblastoma. Deletion of a retinoblastoma gene is a common primary mechanism. Other abnormalities are more rare. To our knowledge, a balanced translocation of the long arms of the X and 13 chromosomes associated with bilateral retinoblastoma has been reported five times. We report an unbalanced X;13 translocation resulting in partial trisomy 13 and an interstitial deletion of an RB locus. Methods: Case report. Results: A 19-month-old child presented with seizures to the emergency department. A CT scan revealed bilateral intraocular calcification, and retinoblastoma (RB) was confirmed with an ophthalmic exam. Abnormal facies and developmental delay were noted. A partial trisomy derived from the translocation of X;13 was observed in both bone marrow and peripheral blood cells. Fluorescence in-situ hybridization (FISH) studies confirmed triplication of a region on the q arm of chromosome 13 spanning the RB locus. One of the normal chromosome 13 homologues had an interstitial deletion of the RB locus since no signal was observed for the RB-1 probe despite the visible presence of the 13q14 region. Additional evidence of the interstitial deletion is supported by the typical facial features and developmental delay found. Presumably, the translocated X underwent X inactivation precluding systemic features typically observed in trisomy 13. Parental karyotypes were normal. The chromosomal abnormality was a de-novo constitutional event. Conclusions: Only two RB loci were present in this patient despite triplication of 13q. The third locus was deleted. We believe that the second locus was not expressed due to X inactivation of the RB gene on the der(X)t(Xq:13q) chromosome. The emergence of bilateral retinoblastoma points towards lack of heterozygosity at the third and last remaining RB loci in tumor cells. To our knowledge, an unbalanced translocation resulting in partial trisomy 13 with retinoblastoma has not been previously reported.
遗传性疾病的代谢和分子基础（Scriver, C. R.、Beaudet, A. L.、Sly, W. S.、Valle, D.、Childs, B.、Kinzler, K. W. 和 Vogelstein, B. 编辑，第 8 版，McGraw-
DOI：
10.1023/a:1017418800320
发表时间：
2004
期刊：
Biochemistry (Moscow)
影响因子：
--
作者：
S. Yap;Nadine Gougeard;A. Hart;B. Barcelona;V. Rubio
通讯作者：
V. Rubio