Table 1.

Most common mutations causing G6PD deficiency worldwide.

Exon/intron location	Nucleotidic substitution in cDNA	Aminoacid substitution	Designation	Class	KM NADP+ (μM)	Reference
Exon 5, nt 376	A → G	N126D	G6PD A	III	12.97	[29]
Exon 4, nt 202 Exon 5, nt 376	G → A A → G	V68M N126D	G6PD A–	III	15	[155]
Exon 6, nt 563	C → T	S188F	G6PD Med	II	2.43	[29]
Exon 8, nt 844	G → C	D282H	G6PD Seattle	III	2.4–2.8	[29]
Exon 11, nt 1260	C → T	R454C	G6PD Union	II	8.6	[40]
Exon 12, nt 1376	G → T	R459L	G6PD Canton	II	14.7	[40]

A lower level of enzyme activity in the erythrocytes of genetically deficient individuals might be due to a normal rate of synthesis of an enzyme of low catalytic efficiency, a decreased rate of synthesis of a normally active enzyme, an increased lability of the variant enzyme or a combined mechanism. The clinical phenotype depends on the mutation location in the 3D structure of the protein. G6PD A^– is a more labile enzyme with normal rate of synthesis.