Deletion and duplication at DYS448 and DYS626 loci: unexpected patterns within the AZFc region of the Y-chromosome

Increasing the knowledge of multiple and microstructural events within the Y-chromosome may prove useful to better characterize abnormal short tandem repeats patterns complicating DNA profile interpretation. On the long arm of the human Y-chromosome, such structural rearrangements were observed in azoospermia factor regions (AZFa, AZFb, AZFc) that play an important role in male fertility and also host Y-STRs commonly used in forensic genetics. Here, we describe two cases, involving two males formerly included in an Italian population study, where DYS448 and DYS626 loci, located within the AZFc region, simultaneously displayed a double deletion in one case and a double duplication in the other. With the aim of better defining the size of both events, low and high-resolution mapping by means of 16 sequencetagged sites was performed, and unexpected discontinued patterns within the palindromic segments b1/b3 of the AZFc were identified. Extending the analysis to their respective male relatives revealed unaltered transmission of the patterns along the two pedigrees. Reviewing literature data describing DYS448-DYS626 deletion and duplication suggested no close correlation between the occurrence of multiple/ microstructural events and geographical origin.