Complement factor 5 (C5) p.A252T mutation is prevalent in, but not restricted to, sub-Saharan Africa: implications for the susceptibility to meningococcal disease.

Complement C5 deficiency (C5D) is a rare primary immunodeficiency associated with recurrent infections, particularly meningitis, by Neisseria species. To date, studies to elucidate the molecular basis of hereditary C5D have included fewer than 40 families, and most C5 mutations (13 of 17) have been found in single families. However, the recently described C5 p.

A complement C5 gene mutation, c.754G>A:p.A252T, is common in the Western Cape, South Africa and found to be homozygous in seven percent of Black African meningococcal disease cases.

Patients with genetically determined deficiency of complement component 5 are usually diagnosed because of recurrent invasive Neisseria meningitidis infections. Approximately 40 individual cases have been diagnosed worldwide. Nevertheless, reports of the responsible genetic defects have been sporadic, and we know of no previous reports of C5 deficiency being associated with a number of independent meningococcal disease cases in particular communities.

Complement component C5 and C6 mutation screening indicated in meningococcal disease in South Africa.

Background: Invasive meningococcal disease (MD), caused by Neisseria meningitidis infection, is endemic in South Africa, with a seasonal peak in winter and spring. There were 2 432 laboratory-confirmed cases between 2006 and 2010. Human deficiency of the fifth complement component (C5D) or complete absence of the sixth component (C6Q0) leads to increased risk of MD, which is often recurrent.

Complete deficiency of the sixth complement component (C6Q0), susceptibility to Neisseria meningitidis infections and analysis of the frequencies of C6Q0 gene defects in South Africans.

Complete complement component 6 deficiency (C6Q0) is a co-dominant genetic disease presenting as increased susceptibility to invasive Neisseria meningitidis infections. Affected individuals have two affected alleles which can be homozygous or compound heterozygous for the particular gene defects they carry. This disorder has been diagnosed relatively frequently in Western Cape South Africans.

Characterization of a large genomic deletion in four Irish families with C7 deficiency.

Inherited deficiency of the seventh complement component (C7) is associated with increased susceptibility to Neisseria meningitidis infections. The disease is rare in most Western countries. Here we report new investigations of a large, but incompletely characterized genomic deletion of exons 8 and 9 [c.