Abstract
BACKGROUND: Primary cilia are membrane-bound microtubule-based protuberances of the cell membrane projecting to the extracellular environment. While little attention was paid to this subcellular structure over a long time, recent research has highlighted multiple cellular functions of primary cilia and has brought cilia to the focus of medical and cell biological research. FINDINGS: Cilia are nowadays considered to be crucial cellular structures controlling diverse intracellular signaling cascades. Dysfunction of cilia leads to a pleiotropic group of diseases ranging from cystic kidney disease via neurologic disorders to metabolic phenotypes and cardiac malformations. According to the underlying cellular pathophysiology, these diverse disorders have been subsumed under the term "ciliopathies". CONCLUSIONS: The work on rare human ciliopathies has strongly deepened our genetic and cell biological understanding of multiple diseases and cellular events thus ultimately leading to clinical trials of novel therapeutic approaches. This review focuses on some of the important developments in ciliopathy research.