High prevalence of complement C7 deficiency among healthy blood donors of Moroccan Jewish ancestry

The incidence of the specific component deficiencies in various ethnic grou ps is not known, although there appears to be an ethnic predilection for C6 and C8 alpha-gamma deficiencies in blacks, whereas C7 and C8 beta deficien cies are predominantly noted in Caucasians. Infectious diseases, particular ly recurrent meningococcal infections, are observed more commonly with late component deficiencies. In the current study, we have simplified the PCR t echnique by using site-directed mutagenesis and designer primers in a cohor t of Israeli Moroccan Jewish blood donors to ascertain allele frequency in this ethnic group, which, based on earlier studies, was considered to be at risk for C7 deficiency. The total mutant allele frequency in this ethnic c ohort was 1.1% of a total of 365 healthy Israeli Moroccan Jews, including o ne homozygote. The identification of mutant alleles was efficient and inexp ensive, and hence a large cohort was studied. The finding of complement def iciency identifies individuals at risk for Neisserial infections, which are known to be potentially life-threatening, Conversely, when a patient of Mo roccan ancestry is diagnosed with a Neisserial infection, it is important t o determine the complement status. (C) 2001 Wiley-Liss, Inc.