XY-QUADRIVALENT ASSOCIATION AND STERILITY IN A MAN CARRIER OF A RECIPROCAL AUTOSOMAL TRANSLOCATION INVOLVING THE WHOLE-ARM OF AN ACROCENTRIC CHROMOSOME T(2-15)(Q21.3-CEN)

Meiotic and synaptonemal complex studies using electron microscopy wer e carried out on an infertile man with a 46,XY t(2q;15p). Synaptonemal complex analysis showed terminal asynapsis in the totality of quadriv alents and a high and significant frequency of association with the XY vesicle (80%), possibly related to the high amount of satellite DNA o f the acrocentric chromosome 15. In this translocation carrier, the XY quadrivalent association at pachytene stage is positively correlated with the degree of spermatogenic breakdown after pachytene stage. Whet her association with the non-paired segment represents the causative f actor or only a secondary effect has still to be clarified.