Chromosomal heteromorphisms (CHMs) are currently largely disregarded in human genetic diagnostics. One exception is der(Y)t(Y;acro)(q12;p1?2), which has at least been mentioned in karyotypes and discussed in reports. This derivative is frequently observed in healthy males with idiopathic infertility, which is not uncommon for CHMs. Here, we present the first systematic fluorescence in situ hybridization (FISH)-based study of 7 carriers of der(Y)t(Y;acro)(q12;p1?2). Specific probes for 15p11.2 (D15Z1) and 22p11.2 (D22Z4) were applied to answer the question of whether either of the short arms may be involved in the formation of the derivative Y-chromosome. In 6 out of 7 cases, specific staining was achieved using the D15Z1 probe, while the derivative acrocentric chromosomal region was not positive for D22Z4 in any of the 7 cases.

In conclusion, this study implies that the acrocentric chromosomal region is derived from chromosome 15 in the majority of cases with der(Y)t(Y;acro)(q12;p1?2).

染色体异态性（CHM）目前在人类遗传诊断中很大程度上被忽视。一个例外是 der(Y)t(Y;acro)(q12;p1?2)，它至少在核型中被提及并在报告中讨论过。这种衍生物经常在患有特发性不孕症的健康男性中观察到，这在 CHM 中并不少见。在这里，我们提出了第一个基于系统荧光原位杂交 (FISH) 的对 der(Y)t(Y;acro)(q12;p1?2) 的 7 个载体的研究。应用 15p11.2 (D15Z1) 和 22p11.2 (D22Z4) 的特异性探针来回答任何一个短臂是否可能参与衍生 Y 染色体形成的问题。在 7 例中有 6 例，使用 D15Z1 探针实现了特异性染色，而在 7 例中，衍生的顶着丝粒染色体区域对 D22Z4 均未呈阳性。

总之，这项研究表明，在大多数 der(Y)t(Y;acro)(q12;p1?2) 病例中，近端着丝粒染色体区域源自 15 号染色体。