Detection of t(X;Y) in 2 XX males using fluorescent in situ hybridization

Males with a 46,XX karyotype generally have Y chromosomal material translocated to the pseudoautosomal region of the X chromosome. We have delineated two such cases using two color fluorescent in situ hybridization with probes from the short arm (DYZ2), centromere (DYZ3), and long arm (DYZ1) of the Y chromosome and a centromeric probes for the X chromosome (DXZ1). Using these techniques, the two patients are identified as having the karyotype 46,X,der(X)t(X;Y) (p22;p11) and a phenotype consistant with this translocation. Azoospermia in these patients is explained by the absence of Y long arm material including the recently identified candidate gene family for spermatogenesis.