An estimate on the frequency of duplicated haplotypes and silent alleles of human C4 protein polymorphism. II. Investigations in healthy Negro families.
The first investigation of complete MHC marker data in South African Negroes by segregation analysis in 11 families with up to three generations is presented, including quantitative evaluation of C4 allotype patterns and C4 beta chain determinations according to Steuer et al. (1). The frequency of homo- and heteroduplicated, hybrid, and non-expressed C4 alleles was determined from C4 protein phenotyping, including C4 alpha and beta chains, quantitative estimates of the relative electrophoretic C4 banding patterns by scanning densitometry, and from the other classical MHC markers by submitting all results to the family analysis program (FAP). From unrelated non-diseased individuals (n = 105) in these families with 62 haplotypes, the following frequencies were observed for non-expressed alleles: C4A*Q0 0.1189, C4B*Q0 0.2552, and for the total of heteroduplicated alleles: C4A 0.0645, C4B 0.0608. Applying additionally quantitative determinations of C4 banding patterns, homoduplications such as C4A*3 A*3, C4B*1 B*1, C4B*3 B*3, and the heteroduplication C4A*3 A*2 were assumed. In the investigated individuals the heteroduplications of C4A*12 and C4A*3 with the A*91 allele and of C4B*2 with C4B*92 were observed. It was concluded that not only allele frequencies but also the frequency of heteroduplications seems to be of specific ethnic character. Furthermore, the prior hypothesis that deletion or non-expression at one C4 locus is accompanied by duplication at the other was only confirmed for non-expressed B-alleles with C4A*3 A*91 or C4A*12 A*91.(ABSTRACT TRUNCATED AT 250 WORDS)
Steuer
M K
MK
Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde, Universität Regensburg, Federal Republic of Germany.
Oudshoorn
M
M
Brenden
M
M
Fimmers
R
R
Neugebauer
M
M
du Toit
E
E
Baur
M P
MP
Mauff
G
G
D000483:Alleles; D044383:Black People / Q000235:genetics*; D003181:Complement C4 / Q000235:genetics*; D003720:Densitometry; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic; D013019:South Africa
D003181:Complement C4