Nucleotide sequence of CYBB around predisposition 88-93 from the patient and a healthy control. (A) Genomic DNA from the leukocytes of a healthy control. (B) Genomic DNA from the leukocytes of the patient (no. 9). The normal CYBB sequence TACCGG is changed in the patient into a mixture with TAGGTG, indicating that she is a heterozygote for this 3-nt mutation. (C) Leukocyte cDNA from a healthy control. (D) Leukocyte cDNA from the patient (no. 9) shows an apparent homozygous mutant sequence TAGGTG. The underlying signal is from another exon, apparently due to some incorrect mRNA splicing.