Yokoyama-Rebollar Emiy, Ruiz-Herrera Adriana, Lieberman-Hernández Esther, Del Castillo-Ruiz Victoria, Sánchez-Sandoval Silvia, Ávila-Flores Silvia M, Castrillo José Luis
Departamento de Genética Humana, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C. Colonia Insurgentes Cuicuilco. Delegación Coyoacán C.P. 04530. México, D.F., México.
Laboratorio de Citogenética, Departamento de Genética Humana, Instituto Nacional de Pediatría, D.F., México.
Mol Cytogenet. 2015 Apr 9;8:27. doi: 10.1186/s13039-015-0127-6. eCollection 2015.
The 15q11q13 region is subject to imprinting and is involved in various structural rearrangements. Less than 1% of Angelman Syndrome patients are due to translocations involving 15q11q13. These translocations can arise de novo or result from the segregation of chromosomes involved in a familial balanced translocation.
A 5-year-old Mexican girl presented with developmental delay, minor dysmorphic features and history of exotropia. G-banding chromosome analysis established the diagnosis of Angelman Syndrome resulting from a familial translocation t(10;15) involving the 15q11.2 region. The available family members were studied using banding and molecular cytogenetic techniques, including Microarray-based Comparative Genomic Hybridization, which revealed additional unexpected results: a coincidental and smaller 15q deletion, asymptomatic duplications in 15q11.2 and Xp22.31 regions.
This report demonstrates the usefulness of array CGH for a detailed characterization of familial translocations, including the detection of submicroscopic copy number variations, which would otherwise be missed by karyotype analysis alone. Our report also expands two molecularly characterized rare patient cohorts: Angelman Syndrome patients due to familial translocations and patients with 15q11.2 duplications of paternal origin.
15q11q13区域存在印记现象，并参与各种结构重排。不到1%的天使综合征患者是由涉及15q11q13的易位所致。这些易位可能是新发的，也可能是家族性平衡易位中涉及的染色体分离的结果。
一名5岁墨西哥女孩表现出发育迟缓、轻微畸形特征和外斜视病史。G显带染色体分析确诊为天使综合征，病因是涉及15q11.2区域的家族性易位t(10;15)。使用显带和分子细胞遗传学技术对现有家庭成员进行研究，包括基于微阵列的比较基因组杂交，结果发现了其他意外结果：一个巧合的较小的15q缺失、15q11.2和Xp22.31区域的无症状重复。
本报告证明了阵列比较基因组杂交在详细表征家族性易位方面的有用性，包括检测亚微观拷贝数变异，否则仅靠核型分析会遗漏这些变异。我们的报告还扩展了两个分子特征明确的罕见患者队列：因家族性易位导致的天使综合征患者和父源15q11.2重复的患者。
