At NGS analysis, several CHH probands harbored a total of 9 rare sequence variants and 4 novel sequence variants in genes previously identified to be associated with nHH and/or KS: FGFR1 (n 1), PROK2 (n 2), TAC3R (n 1), DCC (n 2), WDR11 (n 1), IL17RD (n 2), DUSP6 (n 1) and KAL1 (n 1), FGF8 (n 1), and IL17RD (n 1), respectively. This evidence concerns the gene PROK2 and cartilage-hair hypoplasia.