CILIARY DISEASES

Abstract

The immotile-cilia syndrome has been characterized as an inborn disease in which cilia (and sperm tails) are unable to move in a normal and effective manner (Afzelius, Science 193, 317, 1976). When studied with the electron microscope the ciliary axoneme was found to lack the dynein arms, i.e. the components that are responsible for converting the chemically bound energy into microtubule sliding and hence ciliary movements. Later other types of defects in the ciliary axoneme have been found, such as deficiencies in the so called spokes or in the nexin links. By now our clinical material includes 40 children (aged 0 - 18 years), 18 of which have situs inversus. (There are also 35 adult cases, 20 of which have situs inversus.) Of the forty children about half the cases have a markedly lowered number of dynein arms and in most cases the orientation also is poor. In others the number of dynein arms was only slightly decreased or the dynein arms were shorter than normally. Some had defective spokes or a disorganized axoneme which probably was caused by defective nexin links. In three cases no ciliated cells were seen. Two children had cilia with a normal ultrastructure and a third case had cilia that appeared normal except for the length that was twice the normal one. Evidently the immotile-cilia syndrome is a genetically heterogeneous disease although it is clinically homogeneous. These data can be compared with data from three cases suffering from cystic fibrosis and having cilia with a normal ultra-structure except for the ciliary orientation that in one case was poor.