Unique karyotype: mos 46,X,dic(X;Y)(p22.33;p11.32)/ 45,X/45,dic(X;Y)(p22.33;p11.32) in an Egyptian patient with Ovotesticular disorder of sexual development

Ovotesticular disorder of sexual development (OT-DSD) is an unusual form of DSD, characterized by the coexistence of testicular and ovarian tissue in the same individual. In this report, we present clinical, cytogenetic and molecular data of an Egyptian patient with ambiguous genitalia and OT-DSD, who had a unique karyotype comprising 3 different cell lines: mos 46,X,dic(X;Y)(p22.33;p11.32)/45,X/ 45,dic(X;Y)(p22.33;p11.32). This mosaic karyotype probably represents 2 different events: abnormal recombination between the X and Y chromosomes during paternal meiosis and postzygotic abnormality in mitotic segregation of the dic(X;Y) chromosome, resulting in a mosaic karyotype. The presence of the sex-determining region Y (SRY) gene explains the development of testicular tissue. On the other hand, other factors, including the presence of a 45,X cell line, partial SRY deletion, X inactivation pattern, and position effect, could be contributed to genital ambiguity. Explanation of the patient's phenotype in relation to the genotype is discussed with a literature review. We conclude that FISH analysis with X- and Y-specific probes and molecular analysis of the SRY gene are highly recommended and allow accurate diagnosis for optimal management of cases with ambiguous genitalia.