An international collaborative initiative to screen primary ciliary dyskinesia with high-speed video microscopy and nasal nitric oxide at a tertiary referral centre in South India

BACKGROUND AND OBJECTIVE: To screen patients with suspected primary ciliary dyskinesia (PCD) using high-speed video microscopy analysis (HSVA) and/or nasal nitric oxide (nNO) through an international collaborative initiative between GKNM Hospital, Coimbatore, India, and the PCD Centre, University Hospital Southampton, UK. METHODS: Children and adults up to 30 years of age with clinical features suggestive of PCD were recruited. HSVA was performed on nasal brushing biopsies for all participants. Nasal NO was measured, when feasible, in patients aged ≥5 years using a portable electrochemical NIOX VERO® device. Online multidisciplinary team meetings involving both centres reviewed and interpreted the results. Patients who tested positive on at least one of the two screening tests were classified as PCD screen-positive. Due to resource constraints, only a subset of screen-positive patients underwent genetic testing. RESULTS: Among the 113 patients screened, 68 (60.1%) were PCD screen-positive. Next-generation sequencing was performed in 26 of these 68 patients, and PCD was genetically confirmed in 14 cases. The median age at diagnosis was 8.5 years. CONCLUSION: In resource-limited settings, diagnosis of PCD is often delayed. A combined screening strategy using HSVA and nasal NO testing can help identify likely PCD cases and facilitate early intervention. HSVA and nNO testing were found to be complementary in the screening of PCD. Genetic testing was used in a subset of patients to confirm diagnosis and was conclusive in 54% of tested.