Objective: Up to now, observation of familial undescended testis (UDT) has been confined to the description of individual cases. The aim of our study was to evaluate the frequency of a positive family history and of associated urological anomalies in family members, and to calculate the risk of newborn male individuals having UDT if a family member is affected.
Methods: A total of 374 patients who underwent surgery because of UDT and 374 controls without UDT were interviewed by means of a special questionnaire. We asked for a family history of UDT, as well as for other urogenital anomalies (varicocele, hydrocele, hypospadias, testicular cancer, renal anomalies). For statistical analysis the odds ratio was calculated.
Results: Of the analysed patients, 85 (22.73%) had family members with UDT versus 7.5% of the control group. Of these 85 cases, brothers were involved in 37.3%, fathers in 35.2%, uncles in 23.5%, cousins in 16.5%, great-cousins in 8.2% and grandfathers in 7.1%. The risk of UDT in a newborn male is 3.6-fold overall, and 6.9-fold if a brother and 4.6-fold if the father is affected. The rate of family members with UDT and/or other urogenital anomalies in the patient group was nearly 2-fold higher than in the control group.
Conclusions: Due to the increased familial risk and the higher percentage of a positive family history for UDT and other urogenital anomalies in patients with UDT, a genetic predisposition seems probable.