Cytogenetic Spectrum of Ovotesticular Difference of Sex Development (OT DSD) among a Large Cohort of DSD Patients and Literature Review

Ovotesticular difference of sex development (OT DSD) is a rare genetic disorder with an incidence of about 1/100,000 live births. The majority of OT DSD patients show a 46,XX karyotype, others may have 46,XX/46,XY chimerism or exhibit various mosaic sex chromosome combinations, and less commonly they may have a 46,XY karyotype. The aim of this work is to report the clinical, pathological, and karyotypic variations in OT DSD patients diagnosed among a large cohort of DSD patients. The study included 10 patients thoroughly evaluated for clinical, genital, and hormonal abnormalities and subjected to imaging studies, laparoscopy with gonadal biopsy, karyotype, and FISH analysis. The current study revealed a greater percentage of mosaic cell line combinations than previously reported and showed variable cytogenetic abnormalities, including the rare isodicentric (Y)(p11.32) abnormality and X;Y translocation. The study also revealed a unique pattern of gonadal type and combination frequencies. To our knowledge, this is the first study on OT DSD patients among a large cohort of DSD patients in Egypt and the Middle East.