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

The potential of assisted reproduction techniques to transmit genetic defec ts causing male infertility raises questions concerning the need for a syst ematic genetic screen and counselling. Deletions of the long arm of the Y c hromosome 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 laborat ories. The incidence of Y microdeletions varies widely between studies, fro m 1-55%. These differences are mainly related to study design. The highest incidence of microdeletions has been reported in well selected idiopathic a zoospermic patients. Since microdeletions have been reported also in nonidi opathic patients, it is important to define what is the deletion frequency in unselected patients. We report Y chromosome microdeletion screening in 1 34 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 popula tion revealed a deletion incidence of 4.7% in azoospermic/ cryptozoospermic patients; an incidence of 7%, in idiopathic patients and an incidence of 1 6% 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 deletio ns were found. Further data on gene specific screening are needed especiall y for selected idiopathic patients.