First neonatal case of primary ciliary dyskinesia caused by a pathogenic DRC1 variant presenting with recurrent atelectasis and airway hypersecretion: a case report and literature review.

backgroundPrimary ciliary dyskinesia (PCD) is a relatively rare hereditary disorder. Pathogenic variants in DRC1 are prevalent in East Asian populations and are frequently associated with situs solitus, which often obscures clinical suspicion. More than 80% of affected neonates with PCD present with respiratory distress; however, definitive diagnosis often requires specialized investigations, and many cases remain undiagnosed. Because PCD can progress to chronic obstructive lung disease and bronchiectasis, early diagnosis and appropriate management are essential. We report the first neonatal case of PCD caused by a pathogenic DRC1 variant, in which recurrent atelectasis and airway hypersecretion prompted evaluation and ultimately led to a definitive diagnosis. CASE PRESENTATION　: A female infant was born at 37 weeks of gestation via uncomplicated vaginal delivery, with a birth weight of 2,294 g. She had no respiratory distress immediately after birth but developed subcostal retractions and hypoxemia (oxygen saturation around 90%) on day 1 of life (DOL 1). High-flow nasal cannula therapy did not improve her respiratory status. On DOL 3, she developed left upper lobe atelectasis and poor feeding. She was intubated on DOL 4 and transferred to our center for further evaluation. Although she was extubated on DOL 5, right upper lobe atelectasis developed, requiring re-intubation on DOL 6. After a second extubation on DOL 7, she continued to exhibit copious airway secretions and required noninvasive positive-pressure ventilation for an additional 11 days. Contrast-enhanced chest computed tomography, laryngoscopy, bronchoscopy, and upper gastrointestinal contrast studies revealed no structural abnormalities. With continued chest physiotherapy and mucolytic treatment, the right upper lobe atelectasis resolved by DOL 22; however, airway secretions remained excessive. Given the recurrent atelectasis and marked secretions, impaired ciliary function was suspected. High-speed video microscopy on DOL 29 demonstrated ciliary motility abnormalities in nearly all sampled epithelial cells. Genetic testing identified a homozygous deletion of exons 1-4 in the DRC1 gene, confirming the diagnosis of PCD. She continued mucolytic therapy and was discharged from the neonatal intensive care unit on DOL 33.

conclusionsRecurrent atelectasis or airway hypersecretion in neonates should raise suspicion for PCD, even in the absence of situs inversus, and targeted diagnostic evaluation should be pursued.