The data include all nonproductive and productive mutations in patients with X-HIgM and normal donors. The targeted nucleotide refers to the base in the underlined position (or two positions; eg, A in the first and second position in the WA motif where W indicates A or T). The mutation frequency of the targeted nucleotide inside a motif equals the number of target nucleotide mutations/the total number of the nucleotide in the motif. The nucleotide mutation frequency outside the motif targeted position(s) equals (the total number of specific base mutations in the sequence − the number of targeted nucleotide mutations in the motif)/(the total number of the base in the sequence − the number of target nucleotides inside the motif). The extent of targeting was determined by calculating the fold difference between the mutation frequency inside versus outside a motif.

Significant (P < .02) difference in the nucleotide mutation frequency inside a motif versus outside a motif.

Significant (P < .02) difference in the nucleotide mutation frequency in nonproductive versus productive rearrangements.