Received July 15, 2015
Accepted September 25, 2015

Objective: The aim of this paper was to estimate the frequency and types of mutations in key candidate genes involved in spermatogenesis, and their potential role as a cause of azoospermia /cryptozoospermia. Patients and Methods: The sequencing of the coding region of genes DBY, RBMY, DAZ, CDY and BPY2, excluding the promoter region, was performed in a series of 25 patients with azoospermia or severe oligozoospermia without AZF microdeletions. The exon 3 from the DAZL gene (DAL3) was also sequenced. The sequences obtained were analyzed by ProSeq, DnaSP v5 and compared with the database using Blastn and tblastx. Results: 16 of the 25 patients showed some type of variants, such as transversions, transitions, deletions and/or insertions in the DAZ, DAZL, CDY and RBMY genes. The mutated sequences had between 97 and 99% homology with the specific protein of every gene, except the DAZL (73%) and DAZ (94%) proteins. Conclusions: The variants found have not been described previously, suggesting they could be mutations that might affect protein function.