Identification of a novel mutation in the C6 gene of a Han Chinese C6SD child with meningococcal disease.

Deficiency of the sixth complement component (C6D) is a genetic disease associated with increased susceptibility to Neisseria meningitides infection. Individuals with C6D usually present with recurrent meningococcal disease (MD). According to the patients' C6 levels, C6D is divided into complete genetic deficiency of C6 and subtotal deficiency of C6 (C6SD). The present study reported on a Han Chinese pediatric patient with MD, in whom further investigation revealed a C6SD genetic lesion. A heterozygote nonsense mutation (c.1062C>G/p.Y354*) in the C6 gene was identified by Sanger sequencing. The mutation alters the tyrosine codon at position 354 to a termination codon and results in a truncated protein. In conclusion, the genetic lesion of a pediatric patient with C6SD who was diagnosed due to having MD was investigated and a novel pathogenic mutation in the C6 gene was identified. The study confirmed the clinical diagnosis for this patient with C6SD and also expanded the spectrum of C6 mutations.