Human C7 polymorphism: classification and association analysis with C6

Double replica electroblotting for the simultaneous phenotyping of C6 and C7, and its application to the examination of bloodstains

A new reliable and reproducible technique for the simultaneous determination of C6 and C7 types is presented, which employs double replica electroblotting after isoelectric focusing. It permitted clear discrimination of both C6 and C7 components, and the patterns were nearly comparable to those demonstrated separately. The population data obtained by this new technique fitted the genetic hypothesis. The present double replica electroblotting method was successfully applied to the combined phenotyping of C6 and C7 from bloodstains which were stored at room temperature for up to 4 weeks. The method is quite suitable for medicolegal examination of bloodstains particularly for the saving in the amount of sample.

Polymorphism of the seventh component of complement (C7) in a healthy Caucasian population: an immunoblotting study with neuraminidase-treated samples

Genetic polymorphism of the seventh component of complement (C7) was studied in a healthy Caucasian population using polyacrylamide gel isoelectric focusing of neuraminidase-treated plasma samples and an immunoblotting procedure for the specific detection of C7. Among 248 blood donors, three C7-3/1 heterozygotes were identified, resulting in a C7*3 allele frequency of 0.0061 +/- 0.0035. Neuraminidase treatment of serum or plasma samples is necessary for unequivocal identification of C7*3, which is known to be a hypomorphic variant. This observation is discussed with special reference to previous studies on C7 polymorphism in Caucasian populations, where untreated samples have been used for C7 typing.