Strathdee G, Sutherland R, Jonsson J J, Sataloff R, Kohonen-Corish M, Grady D, Overhauser J
Department of Biochemistry, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Am J Hum Genet. 1997 Apr;60(4):860-8.
The 18q- syndrome is a deletion syndrome that is characterized by mental retardation, hearing loss, midfacial hypoplasia, growth deficiency, and limb anomalies. Most patients with this syndrome have deletions from 18q21-qter. We report on three patients with deletions of 18q23. A mother and daughter with identical deletions of 18q23 have many of the typical features of the 18q- syndrome, including midfacial hypoplasia and hearing loss. In contrast, the third patient has few of the symptoms of the 18q- syndrome. A contig of the 18q23 region was generated to aid in the mapping of the breakpoints. FISH was used to map both breakpoints to the same YAC clone. Furthermore, somatic-cell hybrids from the daughter and the third patient were isolated. The mapping results of sequence-tagged sites relative to the two breakpoints were identical, suggesting that the two deletion breakpoints map very close to one another. The analyses of these patients demonstrate that the critical region for the 18q- syndrome maps to 18q23 but that a deletion of 18q23 does not always lead to the clinical features associated with the syndrome. These patients demonstrate the wide phenotypic variability associated with deletions of 18q.
18q-综合征是一种缺失综合征，其特征为智力迟钝、听力丧失、面中部发育不全、生长发育迟缓以及肢体畸形。大多数患有该综合征的患者存在18q21-qter区域的缺失。我们报告了3例18q23缺失的患者。一位母亲和女儿具有相同的18q23缺失，她们具有18q-综合征的许多典型特征，包括面中部发育不全和听力丧失。相比之下，第三位患者几乎没有18q-综合征的症状。构建了18q23区域的重叠群以辅助断点的定位。荧光原位杂交（FISH）用于将两个断点定位到同一个酵母人工染色体（YAC）克隆上。此外，分离出了来自女儿和第三位患者的体细胞杂种。相对于两个断点的序列标签位点的定位结果相同，表明这两个缺失断点彼此非常接近。对这些患者的分析表明，18q-综合征的关键区域定位于18q23，但18q23的缺失并不总是导致与该综合征相关的临床特征。这些患者显示出与18q缺失相关的广泛表型变异性。
