MOLECULAR-BASIS OF HEREDITARY C1Q DEFICIENCY

Complete selective deficiencies of the complement component C1q are ra re genetic disorders which are associated with recurrent infections an d a high prevalence of lupus erythematosus-like symptoms. The improvem ents in molecular biology techniques have facilitated the analysis of such genetic defects to a great extend. To date the basis of C1q defic iencies from 13 families have been studied at the genetic level. In ea ch case single base mutations leading to either termination codons, fr ame shift or amino acid exchanges were thought to be responsible for t hese defects as no other aberrations were found. In addition to DNA an alysis, conventional immunochemical and biochemical methods have contr ibuted substantially to the elucidation of the structural and function al requirements of this complex macromolecule. The present article rev iews the different types of C1q defects in regard to structure and fun ction whereas a detailed presentation on the clinical aspects of C1q d eficiencies will be given in this issue of the Journal (by WALPORT, DA VIES and BOTTO).