Maturation arrest and hypospermatogenesis tissues expressed significantly low levels of DDX3Y testicular transcript (P < 0.001), while the mRNA levels of the other genes were similar to that in tissues from the normal spermatogenesis group.
One of these two patients had DFFRY deletion and the other had DBY deletion; their testicular phenotypes were Sertoli cell-only syndrome and hypospermatogenesis, respectively.
While deletions or even smaller mutations in USP9Y seem to be associated with a testicular phenotype of severe hypospermatogenesis, patients with deletions of DBY may present both Sertoli cell-only syndrome and severe hypospermatogenesis.
The expression of DBY in a cell line from this latter patient is unaltered; this shows that it is the loss of genes lying within the deletion that is responsible for the observed oligozoospermia.