A new case of congenital ficolin-3 deficiency with primary immunodeficiency

Objectives: Human Ficolin-3 (FCN3) is an oligomeric-structured lectin encoded by the FCN3 gene with a pivotal role in the lectin complement pathway. It has anti-microbial activities against bacterial and viral infections and restrains opportunistic pathogens. Mutation in the FCN3 gene is associated with variable clinical manifestations particularly immunologic (infections and autoimmunity) and neurologic complications.

Methods: In this study, we report a 5-year-old boy with a biallelic mutation in the FCN3 gene using clinical and immunological and genetic evaluations (whole exome sequencing).

Results: Our case is the first national and the eighth case worldwide with a confirmed frameshift mutation associated with Ficolin-3 deficiency. He manifested refractory seizures since early infancy, meningitis, pyelonephritis and was diagnosed with severe primary immunodeficiency.

Conclusion: Our case and literature review indicate Ficolin-3 deficiency should be considered in early-onset, premature neonate with a bacterial infection, neurological manifestation and systemic lupus erythematosus like presentations.

Keywords: FCN3 gene mutation; Combined Immunodeficiency disease; Ficolin-3 deficiency; H-ficolin; Hakata antigen.