Figure 1. Consequences of complete or partial loss of CCNO. CCNO is involved in the generation of motile cilia in the MCCs of the respiratory airways, the Fallopian tubes and in the ependymal cells. CCNO mutations result in CILD29, a human syndrome characterized by the destruction of the lung parenchyma, female infertility and hydrocephalus. Most Ccno-/- mice and some Ccno+/- siblings develop communicating hydrocephalus. CCNO heterozygotes or carriers of hypomorphic mutations could constitute the molecular basis for idiopathic Normal Pressure Hydrocephalus (NPH). Epithelia containing MCCs are indicated with a red line.