Disorder of Testicular Development

The development of gonads and their differentiation is a complex procedure that occurs in a fetus during 4–5th week of intrauterine life. Multiple genes and steps are involved in the differentiation and development of gonads and the determination of the sex of the embryo. The 46 XY DSD (a disorder of sex development) can occur due to defects in testis development, inappropriate production, and the action of testosterone. The clinical feature of the condition varies from female external genitalia to micropenis, although Mullerian structures may or may not be present. Testicular tissue is found in some cases, occasionally unilateral or bilateral streak gonads can be found. Patients can present either in the neonatal period or later during puberty with amenorrhea. Detailed clinical examination with relative prenatal, antenatal, and family history should be taken. A complete physical examination of cases, hormonal evaluation including LH, FSH, and testosterone, radiological evaluation for better delineation of anatomy, and karyotyping are required as a part of the workup. Some cases may even require a gonadal biopsy to reach a diagnosis. After confirmation of the diagnosis, parental counseling should be done. Sex rearing of the child is decided by treating team after detailed parent counseling. The chapter includes Swyer syndrome, partial gonadal dysgenesis, and testicular regression. Patients treated well usually have a good quality of life in adulthood.