Five new polymorphisms in the complement C7 gene and their association with C7 deficiency.
Five new polymorphisms in the C7 gene are described: 2 in intron 1, and 1 each in introns 7, 8 and 15. Four of these are single nucleotide exchanges, while the fifth is a T insertion at 10 sequential Ts. Allele frequency data are presented for intervening sequence (IVS)1+ 55 in 6 normal population groups. We present new and updated data in these populations on a previously described C7 polymorphism in exon 13 (cDNA 1792 A/T). We also report the extended haplotypes associated with C7 deficiency for which marker investigation is a useful, and in some cases vital, adjunct to the identification of the gene defects. Almost without exception, a particular haplotype is associated with a particular mutation causing the deficiency state. Haplotyping is especially useful where polymerase chain reaction failure on one chromosome could be a cause for difficulties in detecting a molecular defect due to heterozygosity for large deletions or unidentified variations at the locations of the primers.
Fernie
B A
BA
Molecular Immunopathology Unit, Medical Research Council Centre, Cambridge, UK. baf22@cam.ac.uk
Hobart
M J
MJ
D000483:Alleles; D001483:Base Sequence; D003184:Complement C7 / Q000172:deficiency* / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*
D003184:Complement C7; D005819:Genetic Markers