The smallest dislocated microduplication of Xq27.1 harboring SOX3 gene associated with XX male phenotype

Abstract Objectives Approximately 90% of “XX males” are positive for SRY . However, there are isolated cases of sex reversal associated to other genes in male-determining pathway. Case presentation We describe a 1.3-old patient with 46,XX karyotype, male phenotypic gender and cryptorchidism. Microarray analysis revealed a de novo 273 kb duplication in the Xq27.1 region that contains SOX3 . FISH with probe specific to SOX3 confirmed a unique genomic location of this duplication, dislocated proximal to the centromere of the X chromosome. Conclusions This rare genetic condition was described in few other isolated cases that have associated SOX3 genetic rearrangements and DSD. Microarray and genome-wide-sequencing presents important part in routine diagnostics, and in delineation of other sex-determination-pathway genes in sex reversal disorders.