Linkage analysis localises a Kartagener syndrome gene to a 3.5 cM region on chromosome 15q24-25

Background: Primary ciliary dyskinesia (PCD) is a genetic disorder caused by ciliary immotility/dysmotility due to ultrastructural defects of the cilia. Kartagener syndrome (KS), a subtype of PCD, is characterised by situs inversus accompanying the typical PCD symptoms of bronchiectasis and chronic sinusitis. In most cases, PCD is transmitted as an autosomal recessive trait, but its genetic basis is unclear due to extensive genetic heterogeneity. Methods: In a genome-wide search for PCD loci performed in 52 KS families and in 18 PCD families with no situs inversus present (CDO, ciliary dysfunction-only), the maximal pairwise LOD score of 3.36 with D15S205 in the KS families indicated linkage of a KS locus to the long arm of chromosome 15. In the follow-up study, 65 additional microsatellite markers encompassing D15S205 were analysed. Results: A maximal pairwise LOD score of 4.34 was observed with D15S154, further supporting linkage of the KS, but not the CDO, families to 15q24 - 25. Analysis of heterogeneity and haplotypes suggested linkage to this region in 60% of KS families. Conclusions: Reinforced by the results of multipoint linkage, our analyses indicate that a major KS locus is localised within a 3.5 cM region on 15q, between D15S973 and D15S1037.