A newborn with ambiguous genitalia and a complex X;Y rearrangement

Background: in most mammals, sex is determined at the beginning of gestation by the constitution of the sex chromosomes, xy in males and xx in females.case: here we report an interesting case characterized by ambiguous genitalia and ovotestis in a newborn carrying an apparently female karyotype (46 xx). array comparative genomic hybridization (array-cgh) revealed an unbalanced rearrangement resulting in the deletion of the distal xp and the duplication of the proximal xp contiguous region with presence of the y chromosome from ypter to yq11. fluorescent in situ hybridization (fish) showed that this portion of the y was translocated to the tip of the abnormal x and that the duplicated portion of chromosome x was inverted. altogether, the abnormal chromosome was a dicentric one with the centromere of the y chromosome apparently inactivated.conclusion: the presence within the translocated y chromosome of the sry gene explains the devolopment of testes although it is not clear the reason for the genitalia ambiguity.