Delineating the association between isodicentric chromosome Y and infertility: a retrospective study

To report on 14 infertile patients who had a de novo form of the same isodicentric (idic)(Yq) karyotype with variable degrees of mosaicism.

Retrospective study and review of the literature.

Medical genetics laboratory in a research institute for reproductive biomedicine.

Fourteen infertile patients, including 13 male patients and 1 female patient who had infertility with the same idic(Y) karyotype.

Conventional cytogenetic methods, fluorescence in situ hybridization (FISH) on seminal germ cells and blood, and polymerase chain reaction (PCR)-based molecular approaches.

Karyotype, FISH, and PCR results.

Cytogenetic results revealed abnormal Y chromosome: 45,X/46,X,idic(Y)(q11.22). The FISH technique on blood lymphocytes confirmed a rearranged Y chromosome, with two centromeres and two SRY signals, and marker chromosome with various levels of mosaicism. Moreover, aneuploidy of sex chromosomes was also detected in haploid seminal germ cells. Multiplex PCR analysis of blood samples demonstrated microdeletion in AZFb and AZFc loci.

Because of the resemblance between inversion of chromosome Y and idics(Y), use of confirmatory techniques (e.g., FISH or PCR-based methods) could help prevent medical errors in healthcare systems and precisely delineate chromosomal aberrations in infertile patients when clinical data fail to clarify the cause of infertility.