Cilia are microscopic, eyelash-like projections that stick out from the surface of cells and are involved in sensing the physical environment and chemical signaling. Motile cilia are present in particular organs such as those from the respiratory system, brain ventricules and sperm and non-motile cilia are present in almost all cells.

Ciliary dysfunction causes diseases collectively known as ciliopathies. The number of reported ciliopathies (currently 35) is increasing, as is the number of established (187) and candidate (241) ciliopathy-associated genes.

Rare Disease