Screening for microdeletions of Y chromosome genes in patients undergoing intracytoplasmic sperm injection

The potential of assisted reproduction techniques to transmit genetic defects causing male infertility raises questions concerning the need for a systematic genetic screen and counselling. Deletions of the long arm of the Y chromosome are frequently associated with a failure of spermatogenesis. The search for Y specific sequences and for the gene families RNA binding motif(RBM) and deleted in azoospermia (DAZ) have been introduced in many laboratories. The incidence of Y microdeletions varies widely between studies, from 1-55%. These differences are mainly related to study design. The highest incidence of microdeletions has been reported in well selected idiopathic azoospermic patients. Since microdeletions have been reported also in nonidiopathic patients, it is important to define what is the deletion frequency in unselected patients. We report Y chromosome microdeletion screening in 134 unselected patients undergoing intracytoplasmic sperm injection (ICSI). In the first part of the study we tested six Y chromosome markers. We found three patients with microdeletions (2.2%). Subdivision of the study population revealed a deletion incidence of 4.7% in azoospermic/ cryptozoospermic patients; an incidence of 7%, in idiopathic patients and an incidence of 16% in idiopathic azoospermic/ cryptozoospermic patients. The second part of the study consisted of a screen for the presence of the Y chromosome genes, DBY, CDY, XKRY, elF-1A, DAZ and BPY2. No additional gene-specific deletions were found. Further data on gene specific screening are needed especially for selected idiopathic patients.