ICSI and the transmission of X-autosomal translocation: a three-generation evaluation of X;20 translocation: case report.

Published reports show that male carriers of an X-autosome translocation, which is either inherited from their mother or is de novo, are generally sterile, regardless of the position of the breakpoint in the X chromosome. We report a three-generation propagation of such a translocation in a family with a case of male factor infertility. Due to the condition of severe oligozoospermia, the proband and his wife underwent ICSI, which resulted in the birth of a normal healthy female. Cytogenetic (chromosome) analyses and X-chromosome inactivation (XCI) assays were done on the family. The cytogenetic analysis of the proband, a man with severe oligozoospermia, revealed an X-autosomal translocation, 46,Y,t(X;20)(q10;q10), which was inherited from his mother. His brother had the same translocation. Amniocentesis and post-natal umbilical cord analyses revealed that the female infant carried the same translocation as her father. XCI studies showed highly skewed inactivation of the normal X chromosome in the female infant, her paternal grandmother, and her mother who had a normal karyotype. In contrast to the data from the literature, our study suggests that men with a certain type of X-autosomal translocation could conceive children through ICSI in conditions in which a few spermatogonia are able to complete meiosis II. The literature involving X-autosomal translocation in males is also reviewed and the importance of the study of X-chromosomal inactivation in female infants discussed.