A novel nonsense mutation at Glu-631 in a Spanish family with complement component 7 deficiency

Deficiency of the seventh component of complement (C7D) is frequently assoc iated with recurrent neisserial infections. We report in the present study the genetic basis for C7D in a Spanish family. We used exon specific polyme rase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) an alysis as a screening step for mutations, followed by direct sequencing of the target exon. The mutation in the proband was a homozygous G-to-T transv ersion at nucleotide 1957, the first nucleotide of the codon GAG for Glu-63 1, leading to a stop codon TAG (E631X). Our result provides further evidenc e that the molecular pathogenesis of C7D is heterogeneous.