3.1 G6PD phenotype assignment based on genotype alone
Nine hundred forty-five patients had a genotype result without a G6PD activity result and were assigned a G6PD phenotype based on genotype alone. Of these, 917 patients (97%) were assigned a normal G6PD phenotype, 6 (1%) were assigned a deficient G6PD phenotype, and 22 (2%) patients were assigned a variable G6PD phenotype (Fig. 2).
Of the 917 patients assigned a normal phenotype based on genotype alone, no variant was observed in 465 males and 378 females, consistent with the wild-type genotype result of B and B/B (class IV or normal activity), respectively, 32 males were hemizygous for the class IV A variant, 36 females were heterozygous and 5 females were homozygous for the class IV A variant, and 1 female was heterozygous for the class IV Mira d’Aire variant.
Of the 6 patients assigned a deficient G6PD phenotype based on genotype alone, 5 males were hemizygous for the class III A-(202A_376G) variant and 1 male was hemizygous for the class III Kalyan-Kerala variant.
Of the 22 female patients assigned a variable phenotype based on genotype alone, in 18 patients heterozygous genotypes at the single nucleotide polymorphisms (SNPs) which constitute the A-(202A_376G) variant were observed, a finding consistent with an A-(202A_376G)/B or A/Asahi genotype depending on whether the SNPs are present on the same or separate alleles, respectively; and the other 4 patients had the A-(202A_376G)/A variants.