Bettio D, Venci A, Rizzi N, Negri L, Setti P Levi
Laboratory of Cytogenetics and Molecular Genetics and Operative Unit of Reproductive Medicine, Humanitas Clinical Institute, Rozzano, Milan, Italy.
Hum Reprod. 2006 Apr;21(4):972-5. doi: 10.1093/humrep/dei426. Epub 2006 Feb 16.
Isodicentrics (idic) are structural anomalies of the Y chromosome associated with a 45,X cell line and a broad spectrum of phenotypes. We characterized the rearranged Y chromosomes from three azoospermic males by fluorescence in-situ hybridization (FISH) and PCR. Chromosome study was performed on lymphocytes and testicular biopsy. FISH analysis and PCR established the degree of mosaicism and analysed specific Y regions. Two patients showed a 45,X/46,X,?idic(Y) karyotype with varying degrees of mosaicism. FISH demonstrated the presence of two centromeres and two SRY regions. In the lymphocytes of the third patient, the presence of a small Y-derived marker was also observed. An additional cell line with two idic(Y) was present in the testicular biopsy of the same patient. PCR showed the breakpoint between SY182 (KALY) and SY121 in Yq11.221-q11.222 region in all the cases. For the evaluation of the mosaicism, different tissues must be investigated. The phenotypical sex depends more on the number of copies of the SRY gene rather than on the percentage of 45,X cells, at least in the gonads. The combined use of classical and molecular cytogenetics is necessary for delineating the chromosome regions involved allowing a better genotype-phenotype correlation.
等臂双着丝粒染色体（idic）是与45,X细胞系及广泛表型相关的Y染色体结构异常。我们通过荧光原位杂交（FISH）和聚合酶链反应（PCR）对3例无精子症男性的重排Y染色体进行了特征分析。对淋巴细胞和睾丸活检组织进行了染色体研究。FISH分析和PCR确定了嵌合程度并分析了特定的Y区域。2例患者表现为45,X/46,X,idic(Y)核型，嵌合程度不同。FISH显示存在两个着丝粒和两个SRY区域。在第3例患者的淋巴细胞中，也观察到一个小的Y衍生标记物。在同一患者的睾丸活检组织中存在一个额外的具有两个idic(Y)的细胞系。PCR显示在所有病例中，Yq11.221-q11.222区域的SY182（KALY）和SY121之间存在断点。为评估嵌合情况，必须对不同组织进行研究。表型性别至少在性腺中更多地取决于SRY基因的拷贝数而非45,X细胞的百分比。经典细胞遗传学和分子细胞遗传学的联合应用对于描绘涉及的染色体区域是必要的，从而实现更好的基因型-表型相关性。
