PROK2 and cartilage-hair hypoplasia: Mutated genes, such as anosmin-1 (KAL1), prokineticin 2 (PROK2), prokineticin receptor 2 (PROKR2), GnRH receptor, fibroblast growth factor (FGF) 8, FGF receptor (FGFR) 1 are often found in patients with CHH.