Prenatal diagnosis and prenatal imaging of a de novo 46,X,der(Y)t(X;Y)(p22.13;qll.23) leading to functional disomy for the distal end of the X chromosome short arm from Xp22.13 in a phenotypically male fetus with posterior fossa abnormalities

摘要

One of the primary functions of the X and Y chromosomes is gender phenotype determination. Although multiple genes are involved, key loci such as those at Xp21.3 [ZFX also known as dosage sensitive sex reversal (DSS) locus] and SRY at Ypll.3 are particularly important. The X chromosome in particular also contains a large number of genes which are important for general physical and mental development. Duplications of X chromosome material, which escape the control of X inactivation can therefore lead to a range of physical and mental disabilities. With the dupli-cation of distal X chromosome short arm material, the occurrence of phenotypic sex reversal is a well-reported factor; however, in these cases the duplication includes the DSS locus. We describe here a fetus with 46,X,der(Y)t(X;Y)(p22.13;q11.23)dn presenting with an abnormal mid-trimester anomaly scan and male phenotype indicating exclusion of the DSS locus in the duplicated X chromosome material.