Gutierrez A C, Salamanca F, Lisker R, Segovia A
Ann Genet. 1975 Mar;18(1):45-9.
The presence of a structurally abnormal extra chromosome in a patient with Sturge-Weber syndrome and several members of her family is described. With routine techniques the abnormal chromosome is slightly submetacentric, of the size of a G group chromosome and shows satellites on both arms. C-banding suggested the presence of 2 centromeric regions rather than one, and to explain this finding, in addition to the segregation of the abnormal chromosome through 3 generations and why only one centromere is visible with the usual cytogenetic technique, an hypothesis is advanced suggesting that it resulted from an unusual type of Robertsonian translocation, in which one of the breacks involved directly the centromere of an acrocentric producing a partially dicentric bisate-lited chromosome. The association of Sturge-Weber syndrome with the chromosome abnormality is thought to be fortuitous and the lack of clinical manifestations of all members of this family with the abnormal chromosome, including one with two extra ones, is explained by the fact that it was almost entirely formed by heterochromatic material. The usefulness of C-banding in the study of this patient is strongly emphasized.
本文描述了一名患有斯特奇-韦伯综合征的患者及其家族中几名成员存在一条结构异常的额外染色体的情况。采用常规技术观察到，这条异常染色体略呈亚中着丝粒，大小与G组染色体相同，且双臂均有随体。C带显示存在两个着丝粒区域而非一个。为解释这一发现，除了该异常染色体在三代中的分离情况以及为何用常规细胞遗传学技术仅可见一个着丝粒外，还提出了一种假说，认为它是由一种不寻常的罗伯逊易位导致的，其中一次断裂直接涉及一条近端着丝粒染色体的着丝粒，从而产生了一条部分双着丝粒的双随体染色体。斯特奇-韦伯综合征与该染色体异常的关联被认为是偶然的，而这个家族中所有携带异常染色体的成员，包括一名携带两条额外染色体的成员，均无临床表现，这一现象可由该异常染色体几乎完全由异染色质组成这一事实来解释。本文强烈强调了C带在该患者研究中的作用。
