Hayashi Shin, Kurosawa Kenji, Imoto Issei, Mizutani Shuki, Inazawa Johji
Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan.
Am J Med Genet A. 2005 Nov 15;139(1):32-6. doi: 10.1002/ajmg.a.30982.
Mental retardation (MR) is one of the most common phenotypes in congenital disorders, but in many cases the pathogenesis remains unknown. Here, we report on a 5-year-old boy with mild developmental disability, cranial malformation, minor anomalies, and moderate MR. G-banded chromosome analysis revealed that he carried an apparent balanced translocation, t(1;9)(p34.2;p24). However, our array-based comparative genomic hybridization (CGH-array) analysis detected a cryptic genomic duplication and a deletion at the breakpoints. Further fluorescence in situ hybridization (FISH) showed that the duplication was approximately 7.9 Mb in size at 1p34.3-p33, and the deletion was 4 Mb at 9pter-p24. Although some features of the patient were consistent with those of monosomy 9p-syndrome, his features were not typical of cases of the syndrome, suggesting that the small deletion region involved in 9p may limit his phenotype. On the other hand, interstitial duplication at 1p34.3-p33 is very rare and his phenotype did not match with that in previous reports. CGH-array is a potentially useful technique for investigating cryptic copy-number alterations in cases of apparently balanced chromosome rearrangements in patients with unexpected clinical features.
智力迟钝（MR）是先天性疾病中最常见的表型之一，但在许多情况下其发病机制仍不清楚。在此，我们报告一名5岁男孩，患有轻度发育障碍、颅骨畸形、轻微异常和中度智力迟钝。G显带染色体分析显示他携带一种明显的平衡易位，t(1;9)(p34.2;p24)。然而，我们基于微阵列的比较基因组杂交（CGH-array）分析在断点处检测到一个隐匿的基因组重复和一个缺失。进一步的荧光原位杂交（FISH）显示，重复位于1p34.3-p33，大小约为7.9 Mb，缺失位于9pter-p24，大小为4 Mb。尽管该患者的一些特征与9p单体综合征患者一致，但他的特征并不典型，提示9p上涉及的小缺失区域可能限制了他的表型。另一方面，1p34.3-p33的间质重复非常罕见，且他的表型与既往报道不符。对于具有意外临床特征的患者，若存在明显平衡的染色体重排，CGH-array是一种用于研究隐匿拷贝数改变的潜在有用技术。
