HOXB6 and hypospadias: In total, 79% (22/28) of the proteins encoded by previous reported hypospadias risk associated genes [11] directly or indirectly interacted with SP1 and SP7, whereas six proteins (DGKK, SRD5A2, HOXA4, HOXB6, MAMLD1, BNC2) were not found to be interacted with SP1 and SP7.