Recurrent macroscopic hematuria in a pediatric patient: is it early to diagnose as having type I hereditary C2 deficiency?

Hereditary C2 deficiency is the most common early complement deficiency and characterized by recurrent infections and autoimmunity despite most patients are also asymptomatic. Type I hereditary C2 deficiency is caused by a heterozygous deletion in C2 gene resulting in early stop codon and lack of C2 production. Clinical spectrum may vary and pure nephrological involvement without the presence of recurrent infections is scarce in hereditary C2 deficiency.We report here a previously healthy 14-year-old boy presenting recurrent self-limited macroscopic hematuria and persistently low serum C4 levels, diagnosed as having type I hereditary C2 deficiency with confirming a novel heterozygote deletion (c.1567 + 22_1567 + 43del) in C2 gene. He has been remained asymptomatic for the next 18 months. Since the diagnosis of C2 deficiency was made in the absence of organ-threatening involvement such as immune complex-mediated glomerulonephritis, we think that early diagnosis and optimal follow-up may improve life-span of the patients with hereditary early complement deficiencies.