等臂双着丝粒Y染色体的细胞遗传学相关研究

Cytogenetic studies of isodicentric Y chromosomes

目的研究等臂双着丝粒Y染色体患者表型与核型之间的关系。方法通过研究我院6例性别混乱(DSD)的病例,包括外阴模糊、身材矮小、原发闭经和男性无精子症的患者,进行G显带染色体核型分析,并利用荧光原位杂交技术(FISH)找出标记的结构和断裂点。所有的病人均检测SRY区段。结果 6例患者证实均为等臂双着丝粒Y染色体,其中5例有45,X细胞系嵌合。3例患者(1、2和3号)有相似的断裂点:idicY(qter→p11.32::p11.32→qter),5号患者断裂点为:idicY(pter→q11.1::q11.1→pter),4号患者有相似的断裂点,但为非嵌合体,6号患者断裂点为Yq11.2:idicY(pter→q11.2::q11.2→pter)。其中3例病人的SRY区段正常。结论本研究证实了等臂双着丝粒Y染色体断裂点的不同以及45,X在细胞系中所占的比例的差异导致表型的不同,并且建立了表型和核型的相关性。

Objective： To research the relation between the phenotype and the genotype of isodicentric Y chromosome. Methods： We report on six patients with variable signs of disorders of sex development （DSD） including ambiguous genitalia, short stature, primary amenorrhea, and male infertility with azoospermia, using GTG-banding technique. Fluorescence in situ hybridization （FISH） technique was used to determine the structure and the breakage sites. SRY signals were detected in all patients. Results： All patients are proved to be isodicentric Y chromosomes, and five of them are associated with a 45,X cell line. Three patients （patients 1, 2, and 3） , were found to have similar breakpoints, idicY （qter→pll.32：：pll.32→qter） . Patient 5 revealed the breakpoint： idicY （pter→qll.l：：ql 1.1→pter） . The same breakpoint was detected in patient 4 but in non-mosaic form. Patient 6 had the breakpoint at Yq 11.2： idicY （pter→q i 1.2 ：.q 11.2→pter） . Sequencing of the SRY gene was carried out for three patients with normal results. Conclusion： This study emphasizes the importance of the breakpoint of isodicentric Y chromosomes and the percentage of 45,X cell line to the difference of phenotype, and establishes the relationship between phenotype and karyotype.