Several genes were reported only in syndromic cases; CHD7 (CHARGE syndrome), CR1 (van der Woude syndrome), EFNB1 (craniofrontonasal syndrome), KISS1R (Kallmann syndrome), MID1 (Opitz G/BBB syndrome), REN (van der Woude syndrome), and SOX9 (Pierre-Robin syndrome). Here, CR1 is linked to Kallmann syndrome.