Sequencing electropherograms distinguish among 3 differentψNCF-1/NCF-1 genotypes in the normal population, as well as carriers of the common NCF-1 ΔGT mutation.

Genomic DNA from control individuals unaffected by CGD and obligate carriers of A47°CGD was amplified using primers 2LB2 and 2RB2, which do not distinguish between NCF-1 and ψNCF-1.The figure shows representative electropherograms that cover a 27-bp stretch starting 9 nucleotides downstream from the start of exon 2 (ie, nucleotides 81-107 of the NCF-1 cDNA). In each case, double sequence is observed because it diverges after the initial GT at the start of the exon (not shown). The nucleotide sequences of the pseudogenes and functional gene are shown at the top and bottom of the figure, respectively. Unaffected control individuals fell into 3 distinct groups with approximate ΔGT/GTGT sequence ratios of 2:1, 1:1, and 1:2, as shown, based on peak height measurements. This is well illustrated, for example, by the G (ψNCF-1) and C(NCF-1) at the fifth position. Most obligate carriers of the ΔGT mutation had a much higher ratio of ΔGT (pseudogene) sequence, as seen in the top electropherogram.