Mutations in the genes underlying the defects of the eight complementation groups. For each complementation group, the gene name is given in brackets. Mutations are shown as cDNA position with corresponding amino-acid change in brackets. The numbering for each is based on the cDNA sequence: +1 corresponds to the A of the ATG translation initiation codon. Nonsense and frameshift (fs) mutations are displayed above the gene whereas missense and possible splice site or cryptic splice site (ss) mutations are displayed below. Mutations are based on cblA (Refs , , , , ), cblB (Refs , , ), cblC (Refs , , , , , ), cblD (Refs , ), cblE (Refs , , , , ), cblF (Refs , ), cblG (Refs , , , ) and mut (Refs , , , , , , , , , , , , , , , , , , , ).