Natural transmission of AZFb Y-chromosomal microdeletion from father to his three sons.

Microdeletions of the so-called azoospermia factor (AZF) locus of the Y chromosome long arm (Yq) are an etiological factor of severe oligozoospermia or azoospermia. Patients affected are infertile unless assisted reproductive techniques are used. We report the case of an azoospermic patient (proband) and three brothers who inherited a Yq microdeletion from their father through a spontaneous pregnancy. Leukocyte DNA was extracted using a commercially available kit. A total of 15 pairs of sequence-tagged site (STSs) based primers, spanning the AZFa, b and c regions, were used for screening. All brothers and their father carried a Yq microdeletion of the AZFb subregion where the RNA-binding motif (RBM) gene is located. The proband carried additional deletions of the AZFa and AZFb subregions. RBM deletion can be associated with oligozoospermia allowing natural conception and therefore natural transmission of this genetic anomaly.