The acrocentric part of der(Y)t(Y;acro)(q12;p1?2) contains D15Z1 sequences in the majority of cases

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). Infertility: The origin of a Y-chromosome abnormality Researchers in Germany have clarified the origin of an abnormality in the Y-chromosome linked with infertility. Some chromosome regions are susceptible to variation, such as translocation with segments of other chromosomes. A team of researchers led by Thomas Liehr of the Jena University Hospital, investigated a Y-chromosome abnormality in seven men. Visual analysis of the chromosomes of all seven showed an aberration at the tip of the long arm of the chromosome, probably derived from an exchange with another chromosome. The researchers then used fluorescent probes to characterize the Y-chromosome. A general probe that binds the short arm of any acrocentric chromosome (chrs. 13, 14, 15, 21, 22) generated a signal. Further testing with probes for specific chromosomes revealed that the aberrant region is derived predominantly from the short arm of chromosome 15.