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 distance in the Mainz laboratory, Methodological modifications by laboratories were not accounted for (cooling temperature, relative mobilities between runs). In parallel, all reference samples were also sequenced after exon-specific amplification. As a result, two variants with identical final designations and two variants with different mobilities were shown to conform at the molecular basis exhibiting an amino acid exchange that causes the corresponding change in relative mobility as compared to normal C3F and C3S.