[Further study on heterogeneic basis of complement C8 beta deficiency].
OBJECTIVE
In Caucasian population, the most common molecular basis for C8 beta deficiency s a single C to T transition in exon 9 of C8 beta gene resulting in a stop codon. In previous family studies, two individuals were identified with C8 beta complete deficiency and were found to be only heterozygous for this mutation. This study was conducted by the present authors in search of other possible causes for these two C8 beta deficient individuals.


METHODS
Using direct DNA sequence analysis of all exon-specific PCR products of the C8 beta gene from these two C8 beta deficient patients and their descendants.


RESULTS
Two other C to T transitions at base 298 and 388 in exon 3 were detected, which could also create a termination codon. The descendants from one of the deficient patients were also analysed for the mutations, and it could be demonstrated that the two C to T mutations in exons 9 and 3 are segregating independently.


CONCLUSIONS
These two mutations, which create a termination codon, are sufficient to explain the complete C8 beta deficiency in both patients.
Rao
Li
L
Department of Cardiology, West China College of Preclinical and Forensic Medicine, Key Lab of Biotherapy of Human Disease, Ministry of Education, West China Hospital, Sichuan University, Chengdu, PR China.
Li
Ying-bi
YB
Chen
Guo-di
GD
Zhou
Bin
B
Schneider
Peter M
PM
Zhang
Lin
L
D018389:Codon, Nonsense; D003185:Complement C8 / Q000172:deficiency* / Q000235:genetics*; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005192:Family Health; D005260:Female; D018740:Genetic Heterogeneity; D006801:Humans; D008297:Male; D010375:Pedigree; D017354:Point Mutation
D018389:Codon, Nonsense; D003185:Complement C8; D004247:DNA