Primary ciliary dyskinesia is a disorder that is characterized by chronic respiratory tract infections, abnormally positioned internal organs, and difficulties having biological children (decreased fertility). The signs and symptoms of this condition are caused by abnormal cilia and flagella. Cilia are microscopic, finger-like projections that stick out from the surface of cells. Cilia help cells move where they are needed; they also help move substances within the body. Flagella, which are similar to cilia, are tail-like structures that propel sperm cells forward.

Variants (also called mutations) in one of over 50 different genes can cause primary ciliary dyskinesia. Many of these genes provide instructions for making proteins that form the inner structure of cilia and produce the force needed for cilia to bend. Coordinated back and forth movement of cilia is necessary for the normal functioning of many organs and tissues. The movement of cilia also supports cell transport and helps establish the left-right axis (the imaginary line that separates the left and right sides of the body) during embryonic development.

It is estimated that as many as 1 in 7,500 people worldwide have primary ciliary dyskinesia.

Primary ciliary dyskinesia is typically inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

Published Date: September 22, 2025
Published By: National Institutes of Health