Reference typing report for complement component C3

A comparison of five C3 variant samples has been performed by conventional high-voltage gel electrophoresis in three laboratories (Palermo, Berlin and Mainz). Local designation was shown within SD = +/- 0.75 mm migration dist ance in the Mainz laboratory, Methodological modifications by laboratories were not accounted for (cooling temperature, relative mobilities between ru ns). In parallel, all reference samples were also sequenced after exon-spec ific amplification. As a result, two variants with identical final designat ions and two variants with different mobilities were shown to conform at th e molecular basis exhibiting an amino acid exchange that causes the corresp onding change in relative mobility as compared to normal C3F and C3S.