NCIt definition : Lack of production of functional C2 protein, due to a genetic defect. It is the most
common genetic complement deficiency. Ten percent of C2 deficient patient will develop
systemic lupus erythematosus at an early age. Patients also present with frequent
sinopulmonary infections often with Streptococcus pneumoniae.;
Alternative definition : NICHD: Lack of production of functional C2 protein, due to a genetic defect. It is
the most common genetic complement deficiency. Ten percent of C2 deficient patient
will develop a systemic lupus erythematosus at an early age. Patients also present
with frequent sinopulmonary infections often with Streptococcus pneumoniae.;