title: C4 complement allotypes in juvenile dermatomyositis.
abstract: Twenty probands with juvenile dermatomyositis and their relatives were studied to determine the inherited segregation patterns of class I, II, and III HLA region markers including C4A, C4B, Bf, and C2 complement polymorphisms. The extended haplotype B8, DR3, C4A*Q0, C4B*1, C2*C, and Bf*S was present in 13 of the 20 probands. Three other probands also carried a haplotype with a null allele for C4A and two further probands carried a null allele for C4B; only two probands had no detectable C4 null allele. These data confirm previous studies showing high frequencies of B8 and DR3 in patients with juvenile dermatomyositis, but show that there is a higher association with null alleles of C4. This suggests that the C4 genes are either themselves the disease-susceptibility genes or are in very strong linkage disequilibrium with such genes.
authors.affiliation: Department of Paediatrics, Royal Postgraduate School, Hammersmith Hospital, London, England.
authors.forename: S A
authors.initials: SA
authors.lastname: Robb
authors.forename: A H
authors.initials: AH
authors.lastname: Fielder
authors.forename: C E
authors.initials: CE
authors.lastname: Saunders
authors.forename: N J
authors.initials: NJ
authors.lastname: Davey
authors.forename: M W
authors.initials: MW
authors.lastname: Burley
authors.forename: D H
authors.initials: DH
authors.lastname: Lord
authors.forename: J R
authors.initials: JR
authors.lastname: Batchelor
authors.forename: V
authors.initials: V
authors.lastname: Dubowitz
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D003175:Complement C2 / Q000235:genetics; D003181:Complement C4 / Q000235:genetics*; D003882:Dermatomyositis / Q000235:genetics / Q000276:immunology*; D005260:Female; D006680:HLA Antigens / Q000235:genetics; D015795:HLA-B8 Antigen; D006684:HLA-DR Antigens / Q000235:genetics; D015803:HLA-DR3 Antigen; D006239:Haplotypes; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D013255:Steroid 21-Hydroxylase / Q000235:genetics
chemical_list: D003175:Complement C2; D003181:Complement C4; D006680:HLA Antigens; D015795:HLA-B8 Antigen; D006684:HLA-DR Antigens; D015803:HLA-DR3 Antigen; D013255:Steroid 21-Hydroxylase