Endocrine disruptors, genital development, and hypospadias

Hypospadias is one of the most common congenital anomalies in the United States, occurring in approximately I in 125 live male births. Embryological studies have demonstrated that, depending on where the urethral development arrests, the meatal opening can be anywhere along the shaft of the penis or, in more severe forms, within the scrotum or in the perineum. Currently, the only available treatment is surgery. If left uncorrected, especially in its severe form, there is risk of infertility and psychological effects, such as avoidance of intimate relationships. The cause of hypospadias is largely unknown; however, current epidemiology and laboratory studies have shed new light into the etiology of hypospadias. With recent advancements in molecular biology and microarray technology, it appears that hypospadias is potentially related to disrupted gene expression. Specifically, some of the environmental chemicals are acting as antiandrogens and interfere directly with the action of testosterone-related gene expression. In this paper, we briefly review the normal development of male external genitalia and the prevalence and environmental risk factors related to hypospadias. In addition, we discuss some of the recent laboratory findings that contribute to our current understanding of this disease.