Understanding the new genetics of male infertility

Purpose: Greater than 10% of couples are unable to achieve pregnancy. In at least 30% to 50% of these infertility cases a male factor abnormality is involved. Genetic defects are believed to be the cause of a significant percent of these abnormalities. In fact, defects causing infertility, such as chromosomal disorders and congenital hypothalamic-pituitary-gonadal axis syndromes, have long been recognized. With the development of gene targeting technologies in animal models many genes required for male fertility in animals are known, contributing to our understanding of the etiology of this important health problem. We present not only recognized genetic disorders associated with male infertility, but also its emerging and previously unrecognized genetic etiologies. Materials and Methods: This review is organized to enable the reader to recognize promptly the major types of genetic defects associated with male infertility, their clinical characteristics and appropriate therapeutic approaches. Due to the explosion of current knowledge in this field and to length restrictions the discussion of genetic defects is concise, referencing predominantly review articles relevant to the topic. Results: Assisted reproductive technologies for overcoming sterility resulting from unrecognized etiologies may have important potential consequences for infertile couples and their offspring. Conclusions: Familiarity with the genes associated with male infertility is essential for the urologist to better understand, diagnose and treat the male factor couple.