Recent Advances in Primary Ciliary Dyskinesia

Abstract

Primary ciliary dyskinesia (PCD) is a hereditary disorder with structural and/or functional impairment of the cilia of the whole body. PCD is characterized by chronic sinusitis, bronchiectasis, male infertility and ectopic pregnancy due to impaired ciliary motility. The prevalence of PCD is estimated at 1 in 20,000 live births. Cases with situs inversus are termed “Kartagener’s syndrome” and usually these diagnoses are not difficult to make. However, in cases without situs inversus, the diagnosis can be very difficult. As such, it is most likely that PCD without situs inversus is underdiagnosed at the present time. The diagnosis of PCD is made when the patients have characteristic clinical features and (1) structural abnormalities of the cilia observed with electron microscopy and/or (2) presence of mutations in one of the genes associated with PCD. Electron microscopic diagnosis is not easy because ultrastructural ciliary defects can also be found in a few cilia among the healthy populations. Measuring levels of nasal nitric oxide (NO) concentration is a very useful tool in screening for PCD, because low NO values are a feature of PCD. Hand-held devices using tidal breathing are as useful as stationary devices. The sensitivity and specificity of nasal NO levels of <250 ppb for diagnosing PCD were 97% and 90%, respectively. Some other features can help to diagnose PCD. Frontal sinuses and sphenoid sinuses are hypoplastic. Having a combination of rhinosinusitis, middle ear and lung diseases increases the probability of PCD. The effectiveness of endonasal sinus surgery to treat rhinosinusitis associated with PCD is controversial.