<unk>  deficiency results from mutations in the<unk>  gene.<unk>  gene contributes to the production of<unk> -6-phosphate<unk> . Chemical reactions involving<unk> -6-phosphate<unk>  produce compounds that prevent reactive oxygen species from building up to toxic levels within red blood cells. If reduction in the amount of<unk> -6-phosphate<unk>  or alteration of structure occurs due to the mutations of<unk>  gene, the enzyme loses it protective role and leads to the accumulation of reactive oxygen species and thus damage of red blood cells. Triggers Carriers of the underlying mutation do not show any symptoms unless their red blood cells are exposed to certain triggers, which can be of four main types: * Foods (fava beans is the hallmark trigger for<unk>  mutation carriers), * Certain medicines including aspirin, quinine and other antimalarials derived from quinine. * Moth balls (naphthalene) * Stress from a bacterial or viral infection. Drugs Many substances are potentially harmful to people with<unk>  deficiency. Variation in response to these substances makes individual predictions difficult. Antimalarial drugs that can cause acute hemolysis in people with<unk>  deficiency include primaquine, pamaquine, chloroquine, and hydroxychloroquine. There is evidence that other antimalarials may also exacerbate<unk>  deficiency, but only at higher doses. Sulfonamides (such as sulfanilamide, sulfamethoxazole, and mafenide), thiazolesulfone, methylene blue, and naphthalene should also be avoided by people with<unk>  deficiency as they antagonize folate synthesis, as should certain analgesics (such as phenazopyridine and acetanilide) and a few non-sulfa antibiotics (nalidixic acid, nitrofurantoin, isoniazid, dapsone, and furazolidone). Henna has been known to cause hemolytic crisis in<unk> -deficient infants. Rasburicase is also contraindicated in<unk>  deficiency. High dose intravenous vitamin C has also been known to cause haemolysis in<unk>  deficiency carriers; therefore,<unk>  deficiency testing is routine before infusion of doses of 25 g or more. Genetics Two variants <unk>  A− and<unk>  Mediterranean) are the most common in human populations.<unk>  A− has an occurrence of 10% of Africans and African-Americans while<unk>  Mediterranean is prevalent in the Middle East. The known distribution of the mutated allele is largely limited to people of Mediterranean origins (Spaniards, Italians, Greeks, Armenians, Sephardi Jews and other Semitic peoples). Both variants are believed to stem from a strongly protective effect against Plasmodium falciparum and Plasmodium vivax malaria. It is particularly frequent in the Kurdish Jewish population, wherein approximately 1 in 2 males have the condition and the same rate of females are carriers. It is also common in African American, Saudi Arabian, Sardinian males, some African populations, and Asian groups. All mutations that cause<unk>  deficiency are found on the long arm of the X chromosome, on band Xq28. The<unk>  gene spans some 18.5 kilobases. The following variants and mutations are well-known and described: +Descriptive mutations Mutation Gene Protein Designation Short name IsoformG6PD-Protein OMIM-Code Type Subtype Position Position Structure change Function change<unk> -A(+) Gd-A(+)<unk>  A +305900.0001 Polymorphism nucleotide A→G 376(Exon 5) 126 Asparagine→Aspartic acid (ASN126ASP) No enzyme defect (variant)<unk> -A(-) Gd-A(-)<unk>  A +305900.0002 Substitution nucleotide G→A 376(Exon 5)and202<unk> 8and126 Valine→Methionine (VAL68MET)Asparagine→Aspartic acid (ASN126ASP)<unk> -Mediterranean Gd-Med<unk>  B +305900.0006 Substitution nucleotide C→T 563(Exon<unk>  188 Serine→Phenylalanine (SER188PHE) Class II<unk> -Canton Gd-Canton<unk>  B +305900.0021 Substitution nucleotide G→T 1376 459 Arginine→Leucine (ARG459LEU) Class II<unk> -Chatham Gd-Chatham<unk>  +305900.0003 Substitution nucleotide G→A 1003 335 Alanine→Threonine (ALA335THR) Class II<unk> -Cosenza Gd-Cosenza<unk>  B +305900.0059 Substitution nucleotide G→C 1376 459 Arginine→Proline (ARG459PRO)<unk> -activity (Exon<unk>  163 Glycine→Serine (GLY163SER) Class III<unk> -Orissa Gd-Orissa<unk>  +305900.0047 Substitution nucleotide C→G 131 44 Alanine→Glycine (ALA44GLY) NADP-binding place affected. Higher stability than other variants.<unk> -Asahi Gd-Asahi<unk>  A- +305900.0054 Substitution nucleotide (several) A→G±G→A 376(Exon 5)202 12668 Asparagine→Aspartic acid (ASN126ASP)Valine→Methionine (VAL68MET) Class III.
Glucose-6-phosphate dehydrogenase deficiency
Pyruvate kinase deficiency
Ribose-5-phosphate isomerase deficiency
Hereditary spherocytosis
Glutaminase deficiency
Sickle cell disease
6-phosphogluconate dehydrogenase deficiency
Aldolase A deficiency