title: An unusual combined insertion/deletion polymorphism in intron 10 of the human complement C6 gene.
abstract: Investigation of intron 10 of the human complement C6 gene revealed an unusual combined insertion/deletion polymorphism at position 493: the subsequent 6 bp is deleted and is substituted by a different 26 bp, giving a net gain of 20 bp. The variant shows autosomal co-dominant inheritance. The 26 bp insertion is homologous to a human endogenous retrovirus-type sequence and could tentatively be ascribed to a retroposon. Alternatively, the presence of three copies of a 5 bp direct repeat, an 8 bp palindrome and a 12 bp split symmetrical element could suggest an endogenous, sequence-mediated mutational process. Polymorphisms of this type are extremely rare, although there are several examples of such mutations causing disease.
authors.affiliation: Molecular Immunopathology Unit, Medical Research Council Centre, Cambridge, UK.
authors.forename: B A
authors.initials: BA
authors.lastname: Fernie
authors.forename: M J
authors.initials: MJ
authors.lastname: Hobart
mesh_terms: D001483:Base Sequence; D003183:Complement C6 / Q000235:genetics*; D004262:DNA Restriction Enzymes; D005260:Female; D005819:Genetic Markers; D006720:Homozygote; D006801:Humans; D007438:Introns / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D018626:Retroelements; D017384:Sequence Deletion
chemical_list: D003183:Complement C6; D005819:Genetic Markers; D018626:Retroelements; D004262:DNA Restriction Enzymes