Analysis of the DAZ gene family in cryptorchidism and idiopathic male infertility

Objective To investigate whether partial deletions of the DAZ gene family on the Y chromosome are associated with cryptorchidism, similar to that found for complete AZF deletions. Design Prospective study. Setting University hospital. Patient(s) A total of 193 azoospermic and severely oligozoospermic men: 95 with a history of cryptorchidism and 98 classified as idiopathic. Intervention(s) A two-part study for Y chromosome microdeletions was performed: a polymerase chain reaction (PCR)-based analysis for complete AZF deletions and partial DAZ gene analysis by PCR-restriction digestion assay for single-family variants. Main outcome measure(s) Presence and type of AZF deletions and number of DAZ genes present. Result(s) The frequency of complete AZF deletions was similar in idiopathic (13.3%) and cryptorchid men (11.6%), but partial DAZ deletions were found only in infertile subjects without cryptorchidism (7.1%). The testicular phenotype was similar in men with complete AZF deletions and partial DAZ deletions, therefore the contribution of the other AZF genes in determining the spermatogenic impairment is still unclear. Conclusion(s) Our findings suggest that the loss of only some copies of DAZ is sufficient to lead to severe male infertility, but it is not a frequent finding in cryptorchid men.