Haemoglobin Genotype (Phenotype)

Service Description

Biomarkers: -- Sickle Cell status -- Thalassemia status -- RBC indices Sample: BLOOD Results: Same Day Phlebotomy fee: £0 Haemoglobin (Hb) genotype refers to the specific combination of Hb genes a person inherits from their parents. Hb is the protein in red blood cells responsible for transporting oxygen throughout the body. Hb Variants: The most common Hb types in humans are -- HbA -- HbC -- HbD -- HbE -- HbH -- HbS These variants arise due to different mutations in the genes that produce Hb. Genotype indicates the combination of Hb types a person has, such as -- HbAA Normal -- HbAS Sickle Cell Trait -- HbAC Hb C Trait -- HbAE Hb E Trait -- HbSS Sickle Cell Anaemia -- HbSC Sickle Cell-Hb C Disease -- HbSE Sickle Cell-Hb E Disease -- HbCC Hb C Disease -- HbEE Hb E Disease Thalassemia on the other hand is caused by genetic mutations that affect the production of either alpha (α) or beta (β) globin chains that make up the Hb. Thalassemia is divided into two main types based on which globin chain is affected: -- Alpha Thalassemia: Caused by mutations or deletions in the alpha-globin genes (HBA1 and HBA2) on chromosome 16. * no deletion - normal (αα/αα) * 1 deletion - carrier (silent carrier, α-/αα) * 2 deletions - Mild anaemia (α-/α- or --/αα) * 3 deletions - Moderate to severe anaemia (α-/--, HbH, β4) * 4 deletions - Most severe form (hydrops fetalis, --/--, Hb Bart's) -- Beta Thalassemia: Caused by mutations in the β-globin gene (HBB) on chromosome 11 * no mutations - normal * 1 mutated gene - Mild or no symptoms * 2 mutated genes - Moderate anaemia * 2 severely mutated genes - Severe anaemia requiring regular blood transfusions (Cooley's anaemia) Hb Tree | +---- HbA (Normal adult Hb [95%-98%] α2β2) | | | +---- HbA0 (94%, non-glycated Hb) | | | +---- HbA1 (~6%, glycated Hb) | | | +---- HbA1a | | | +---- HbA1b | | | +---- HbA1c | +---- HbA2 (Minor adult Hb [2%-3%], elevated in β-thalassemia, α2δ2) | +---- HbF (Fetal Hb, foetus [0.5%], elevated in β-thalassemia, α2γ2) | +---- Hb Variants | +---- HbC ( West Africa) | +---- HbD (Punjab variant) | +---- HbE (Southeast Asia, α2β*2) | +---- HbS (Sickle cell) | +---- HbH (α-thalassemia, β4) | +---- Hb Bart's (γ4)