Genetic analysis of the human insulin-like 3 gene in pediatric patients with testicular torsion.

PURPOSE: Testicular torsion (TT) mainly affects boys under 18 years old. To avoid orchiectomy, TT requires an immediate operative management. The etiology of TT is still controversial. Observed familiar recurrence suggests the presence of a genetic involvement. The INSL3 gene consists of two exons, and it is specifically expressed in fetal and adult Leydig cells. In transgenic mice, deletion of this gene was observed an increased testicular mobility and testicular torsion. We have hypothesized the possible involvement of the INSL3 gene as a predisposing factor of human TT.

METHODS: We performed genetic analysis in 25 pediatric patients with unilateral and intravaginal TT (left, n = 13, 56%; right, n = 12, 48%). The age of the patients ranged from 1 to 16 years (median age n = 10.4 ± 5.46 years). In this study, we included two first male cousins affected by TT. Venous peripheral blood samples was obtained after parental written informed consent.

RESULTS: The Thr60Ala polymorphism was detected in exon 1 of INSL3 gene and other 2 rarer variants (rs1047233 and rs1003887) were identified in the 3' untranslated region. These variants are prevalent in patients with TT instead of healthy subjects.

CONCLUSIONS: Additional studies in a larger population are needed to better understand the clinical consequence of the INSL 3 variations founded. This would allow in the future to identify the patients at risk of TT to improve clinical management.