title: Homozygosity for a novel mutation in the C1q C chain gene in a Turkish family with hereditary C1q deficiency.
abstract: Hereditary complete deficiency of complement component C1q is associated with a high prevalence of systemic lupus erythematosus and increased susceptibility to severe recurrent infections. An 11-year-old girl was screened for immunodeficiency due to a history of recurrent meningitis and pneumonia. Immunologic studies revealed absence of classic pathway hemolytic activity and undetectable levels of Clq. Exon-specific amplification of genomic DNA by polymerase chain reaction followed by direct sequence analysis revealed a novel homozygous missense mutation at codon 48 in the C1q C gene causing a glycine-to-arginine substitution affecting the collagen-like region of C1q. No changes were seen in the exons of the A and B chains. The mutation affected both the formation and the secretion of C1q variant molecules. We describe a novel mutation in the C1q C chain gene that leads to an interchange in amino acids resulting in absence of C1q in serum.
authors.affiliation: Department of Pediatric Immunology, Dr. Behçet Uz Children's Hospital, Izmir, Turkey.
authors.forename: N
authors.initials: N
authors.lastname: Gulez
authors.forename: F
authors.initials: F
authors.lastname: Genel
authors.forename: F
authors.initials: F
authors.lastname: Atlihan
authors.forename: B
authors.initials: B
authors.lastname: Gullstrand
authors.forename: L
authors.initials: L
authors.lastname: Skattum
authors.forename: L
authors.initials: L
authors.lastname: Schejbel
authors.forename: P
authors.initials: P
authors.lastname: Garred
authors.forename: L
authors.initials: L
authors.lastname: Truedsson
mesh_terms: D002648:Child; D015922:Complement C1q / Q000172:deficiency* / Q000235:genetics* / Q000276:immunology; D003171:Complement Pathway, Classical / Q000235:genetics / Q000276:immunology; D004247:DNA / Q000737:chemistry / Q000235:genetics; D005260:Female; D006720:Homozygote; D006801:Humans; D008297:Male; D020125:Mutation, Missense / Q000276:immunology; D010375:Pedigree; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D014421:Turkey
chemical_list: D015922:Complement C1q; D004247:DNA