Novel homozygous C3orf67 gene variant associated with primary ciliary dyskinesia in a Saudi pediatric patient: A case report.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by motile cilia dysfunction. Identifying pathogenic variants is essential for diagnosis and personalized care, especially in consanguineous populations like Saudi Arabia. CASE SUMMARY: This report presents a Saudi pediatric patient diagnosed with PCD who exhibited persistent neonatal tachypnea, chronic productive cough, and recurrent otitis media. Whole-exome sequencing revealed a novel homozygous nonsense variant in the C3orf67 gene (NM_198463.2:c.508C>T), resulting in a truncated, non-functional protein. This mutation likely impairs ciliary motility due to the production of a truncated, non-functional protein. The clinical findings were supported by multiple positive sputum cultures and a significant family history of similar symptoms, suggesting a genetic etiology consistent with autosomal recessive inheritance. CONCLUSION: This case highlights the importance of genetic studies in diagnosing PCD, particularly in communities with a high rate of consanguinity. The identification of a novel homozygous variant in the C3orf67 gene expands the known genetic landscape of the disease. Further research is essential to clarify the functional role of C3orf67 in ciliary biology and its contribution to PCD pathogenesis.