Objective: To report on a novel, accurate method for detecting microdeletion involving the DAZ gene in infertile men.
Design: Retrospective clinical study.
Setting: University Infertility Center of Cochin Hospital, Paris, France.
Patient(s): Infertile patients (n = 25) consulting our infertility department during 1998. The patient cohort included subjects with nonobstructive azoospermia and oligoasthenospermia.
Intervention(s): Blood samples were collected from each subject.
Main outcome measure(s): DNA analysis using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE).
Result(s): We used a new molecular genetic strategy to rapidly identify deletions of the Y chromosome that include the DAZ locus. The experiment consists of amplifying simultaneously exon 4 of the DAZ and DAZLA genes with the use of specific primers that are complementary to intronic sequences of these genes. DGGE was used to separate the two PCR products, with good resolution. In infertile men with a microdeletion of the DAZ gene, this method allows amplification of an internal control when a deletion of that portion of the Yq chromosome is observed on a single amplification.
Conclusion(s): This PCR-DGGE method for detection of DAZ gene deletion is simple and fast and does not require the use of radioactive elements. Compared with the classic PCR approach, this new method allows the amplification of the DAZLA copy to be used as an effective internal control in infertile men with microdeletion of the DAZ locus. This procedure could be particularly useful in screening for the DAZ locus in the diagnostic workup of nonobstructive azoospermia and severe oligoasthenoteratozoospermia.