The clinical signs of varicocele typically emerge during the puberty. Varicocele is found in 15% of men in the general population and 25–35% and 50–80% of males presenting with primary and secondary infertility, respectively. Factors contributing to the development and recurrence of varicocele include the abnormalities of the testicular venous drainage and outflow (varicose veins are more common on the left than on the right), the anatomical features of the veins of the testicular and prostatic venous plexus, the patient’s constitution, predisposition to constipation or diarrhea, physical activity. At present, the genetic defects, including the undifferentiated connective tissue dysplasia (UCTD) with hereditary insufficiency of venous valves and the weakness of the testicular vein walls, are thought to play a key role in the formation of a varicocele. Considering the importance of varicocele in the development of male infertility, the role of the UCTD in varicocele formation warrants a detailed investigation to provide an individual approach to patients and predict the disease recurrence.

Keywords: mechanisms of varicocele development, recurrent varicocele, molecular genetic factors, undifferentiated connective tissue dysplasia