The human dynein intermediate chain 2 gene (DNA12): cloning, mapping, expression pattern, and evaluation as a candidate for primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease characte rized by chronic sinusitis and bronchiectasis, and usually associated with hypofertility. Half of the patients present a situs inversus, defining the Kartagener's syndrome. This phenotype results from axonemal abnormalities o f respiratory cilia and sperm flagella, i.e., mainly an absence of dynein a rms. Recently, a candidate-gene approach, based on documented abnormalities of immotile strains of Chlamydomonas reinhardtii, allowed us to identify t he first gene involved in PCD. Following the same strategy, we have charact erized DNAI2, a human gene related to Chlamydomonas IC69, and evaluated its possible involvement in a PCD population characterized by an absence of ou ter dynein arms. DNAI2, which is composed of 14 exons located at 17q25, is highly expressed in trachea and testis. No mutation was found in the DNAI2 coding sequence of the twelve patients investigated. However, ten intrageni c polymorphic sites and an EcoRI RFLP have been identified, allowing the ex clusion of DNAI2 in three consanguineous families.