Moreover, renal agenesis was only found in male patients and occurred in 31.8% KS patients due to KAL1 defects, consistent with the percentage of renal agenesis (31%) in X-linked KS patients in the study by Quinton et al.[13] Therefore, we could imply that renal agenesis may be a marker of KAL1 mutation in KS patients with an estimated sensitivity of 30%. Here, ANOS1 is linked to renal agenesis.