[The absence of the internal arms of dynein as a cause of the immotile cilia syndrome].

Two children aged 9 and 8 years respectively presenting upper and lower respiratory tract infections from early childhood are presented. In both, nasal mucociliary transport was impaired (greater than 30 min) and electron microscopic examination showed cilia devoided of the inner dynein arms. This ciliary defect is one of those recognized as a cause of the Immotile Cilia Syndrome but is very rare, having been described only once in a boy affected with Kartagener's syndrome, which in turn has been reclassified in the Immotile Cilia Syndrome. Therefore the absence of inner dynein arms observed by us in the respiratory cilia of these two children clearly indicated that similarly to many other genetic disorders the immotile cilia syndrome may be determined by many defects in the axonemal structure.