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- Kartagener syndrome (KS) is a rare disorder characterized by defects in the ultrastructure of cilia impairing their motility. It is also referred to as primary ciliary dyskinesia (PCD).
- Three key symptoms definitive for KS include:
- Situs inversus
- Chronic sinusitis
- No gender or racial bias
- Some geographically isolated communities, such as the Amish, may have a higher incidence due to consanguinity.
- Encountered predominantly in neonates and younger children
- Median age of diagnosis: within the first 10 to 14 years of age
Incidence of KS is ~1/15,000 to 30,000 live births.
Prevalence of situs inversus totalis occurs in >60% in the pediatric population and 50% in the adult population:
- Estimated 70 new cases/year
Etiology and Pathophysiology
- KS stems from a disturbance or loss of ultrastructural components of cilia, more specifically dynein arms that help motor cilia.
- It causes cilia and flagella to lose their normal and fast synchronous beat and waveform patterns, which affect ciliary-dependent areas in the body, such as respiratory epithelia, brain ependyma, embryonic node, oviduct, and sperm.
- Chronic upper and lower respiratory tract infections result from lack of mucociliary clearance of mucus and bacteria leading to chronic sinusitis, bronchitis, and permanent lung damage.
- Impairment of ependymal ciliary function within the brain may lead to decreased cerebral spinal flow and thus result in hydrocephalus that may be seen in these patients.
- 40–50% of patients with PCD present with lateralization defects, such as situs inversus totalis, affecting left–right organogenesis due to absent or affected motility within embryonic nodal cilia, which results in random orientation of thoracoabdominal contents that is not genetically predetermined (1).
- Reduced motility of flagellated sperm as well as cilia within oviducts of the fallopian tubes in females may lead to decreased fertility and possible sterility in both genders.
- Heterogeneous, autosomal recessive disorder (2)
- 19 genes associated with PCD to date, which fall into three categories:
- Genes that code for components of the outer or inner dynein arms: DNAH5, DNAH11, DNA11, DNA12, DNAL1, TXNDC3 (2)
- Genes that code for proteins which play a role in axonemal organization of the central pair of microtubules and radial spokes: CCDC39, CCDC40, CCDC164, CCDC103, CCDC40, CCDC164 (2)
- Genes that code for cytoplasmic proteins: KTU, HEATR2, DNAAF1, DNAAF2, DNAAF3, and LRRC6 (2)