Determination of deletion sizes in the MHC-linked complement C4 and steroid 21-hydroxylase genes by pulsed-field gel electrophoresis.
In man, the genes encoding the complement component C4 (C4A, C4B) of the immune system and the steroid 21-hydroxylase enzyme (CYP21A, CYP21B) of adrenal steroid biosynthesis are located in the major histocompatibility complex (MHC). Frequent gene deletions and duplications have been described in the C4 and CYP21 genes, particularly in patients with autoimmune diseases and congenital adrenal hyperplasia. Here we report the determination of deletion sizes in 11 chromosomes with six different deletions. The deletions spanned the C4A+CYP21A, C4B+CYP21A, and C4B+CYP21B gene pairs as determined by standard Southern blot analysis. The deletion size fell within the range of 30-38 kb in all the chromosomes, as determined by pulsed-field gel electrophoresis. Because the deletion sizes in most other gene clusters are more heterogeneous, the results suggest the involvement of a specific mechanism in the generation of C4+CYP21 deletions.
Partanen
J
J
Finnish Red Cross Blood Transfusion Service, Tissue Typing Laboratory, Helsinki, Finland.
Kere
J
J
Wessberg
S
S
Koskimies
S
S
D002872:Chromosome Deletion; D003181:Complement C4 / Q000235:genetics*; D015342:DNA Probes; D004262:DNA Restriction Enzymes; D004586:Electrophoresis; D006239:Haplotypes; D006801:Humans; D006824:Hybridization, Genetic; D008285:Major Histocompatibility Complex; D010641:Phenotype; D013255:Steroid 21-Hydroxylase / Q000235:genetics*; D013250:Steroid Hydroxylases / Q000235:genetics*
D003181:Complement C4; D015342:DNA Probes; D013250:Steroid Hydroxylases; D013255:Steroid 21-Hydroxylase; D004262:DNA Restriction Enzymes