Bronchiectasis in a child with a homozygous DCDC2 gene mutation: A case report.

The DCDC2 (Doublecortin Domain-Containing Protein 2) gene encodes a ciliary protein involved in microtubule polymerization and ciliary assembly. Although DCDC2 has been associated primarily with neuronal migration and ciliopathies affecting the liver and kidneys, its role in pulmonary disease has not been clearly defined. Ciliary dysfunction, particularly in motile cilia of the respiratory tract, can impair mucociliary clearance and lead to bronchiectasis, as seen in primary ciliary dyskinesia. Here, we report a rare case of bronchiectasis associated with a pathogenic DCDC2 (NM_016356.5):c.558del p.(Arg186SerfsTer5) variant, in which other known causes of bronchiectasis were excluded. This finding expands the phenotypic spectrum of DCDC2-related disease, and suggests a potential link between DCDC2 mutations and respiratory involvement. Early recognition of this association might support timely pulmonary screening and intervention to improve long-term outcomes.