CFTR and cartilage-hair hypoplasia: In contrast to CHH, which is a genetically heterogeneous condition (see above), the genetic contribution of CBAVD without kidney anomalies is limited to two genes: (1) Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene for the 75–80% of cases and (2) Adhesion G Protein-Coupled Receptor G2 (ADGRG2) for the 5–10% of cases.